Download Essential Natural Science 1

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Contents
PAGE
1
2
About this book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
Learning to learn Getting closer to the stars! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
The Universe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
Planet Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Learning to learn All creatures great and small . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3
4
5
6
7
Living things . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Invertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Vertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
The plant and fungi kingdoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
The simplest living things . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Learning to learn Rock stars and instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
8 The Earth’s atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
9 The hydrosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
10 Minerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
11 Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Learning to learn It’s elementary! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
12
13
14
Matter and its properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Everything is matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Atoms and elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Vocabulary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Key language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
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Learning to learn
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A
B
ABOUT THIS BOOK
• Look at these illustrations.
Match them to the units
on the opposite page.
Then look at the book,
and check your answers.
Unit .........................
C
D
Unit .........................
F
E
Unit .........................
G
Unit .........................
I
Unit .........................
Unit .........................
Unit .........................
K
Unit .........................
M
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Unit .........................
H
J
L
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N
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Unit .........................
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YOU ALREADY KNOW A LOT!
Work with a partner. Try to answer these questions.
THE UNIVERSE
How many planets in our galaxy can you name?
THE EARTH
How long does it take the Earth to rotate on its axis?
And how long does it take to orbit the Sun?
INVERTEBRATES
Can you name six invertebrates?
PLANTS
Plants are autotrophic: they make their own food.
What is the name of the process by which plants do this?
THE EARTH’S ATMOSPHERE
Can you name three meteorological instruments?
What does each one measure?
THE HYDROSPHERE
Water is present on Earth in gaseous, liquid and
solid form. Name four different places where you
can find water in nature.
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MINERALS
Quartz is a mineral. Can you name any other minerals?
Can you say what each is used for?
MATTER AND ITS PROPERTIES
Oil floats on water.
Which has the greatest density, oil or water?
THE STATES OF MATTER
Look at these three drawings.
They represent a solid, a liquid and a gas.
Can you match each drawing to its state?
1
UNIT
The Universe
What do you remember?
• What are the points of light in this photo?
• What is the difference between …
– a star and a planet?
– a moon and a comet?
STUDY A UNIT
Look at page 8, the first page of Unit 1
• What is the title of the unit?
• How many different sections are there on the page?
What are they about?
Key language
In this unit, you will …
• Learn about the characteristics of the
Universe
• Calculate astronomical sizes and distances
• Analyse the components of the Universe
• Compare sizes: the Sun and the planets
• Create a constellation poster
Describing
Planets are spherical bodies which orbit the Sun.
Asteroids are rocky objects which are irregular in shape.
Comparing
Dwarf planets are smaller than planets.
The Earth is larger than Mercury
Giving instructions
Study the constellations.
Research more about them on the Internet.
• What do you think you will learn about in Unit 1?
Now look at the rest of Unit 1
Content objectives
8
• How many sections are there in this unit?
• What can you find on page 17?
How is this useful?
• What are most of the illustrations about?
Symbols
• Some words are in bold. Why is this?
• The text is recorded on the CD.
• How many activities are there in this unit?
• The information you need is
available on the CD.
• What will you do in the Hands on section, page 15?
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Getting closer to the stars!
Telescopes are used to see objects that are too far away to be seen with the naked eye. They also provide a
closer view of distant things. Astronomers use large telescopes to study the planets, stars, and other objects
in space. Without telescopes, we wouldn’t know much about celestial bodies!
Lenses or mirrors?
Telescopes with lenses are called refracting telescopes.
Lenses bend the light.
The largest telescopes use mirrors instead of lenses
Telescopes with mirrors are called reflecting telescopes.
Mirrors reflect light.
Look through
this end. The
things you
observe seem
closer!
eyepiece: lens
to view the image
focus adjustment:
move this to make
the image clearer
Some telescopes are small enough to be carried in one hand.
Others can be huge, bowl-shaped radio telescopes, more than
300 metres in diameter. This is longer than three football pitches!
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Optical telescopes consist of a long tube, with one end narrower than
the other. They can “perceive” light, just like eyes.
tube
OOPS!
Wrong end!
objective lens: the
lens closest to the
object being viewed
How does a telescope work?
Objects reflect light. This light enters our eyes, and
we see the object. Optical telescopes have an
objective lens: a curved piece of glass at the wide
end. This lens bends the light from the object so
that it forms an image – a picture of the object –
inside the telescope. The light from this image then
goes through the eyepiece, at the narrow end of the
telescope. The eyepiece bends the light back again,
so the object looks big.
tripod: three-legged
stand to support the
telescope
The Gran Telescopio Canarias (GTC),
also called GranTeCan, is a 10.4 m
reflecting telescope, located on a volcanic
peak (2,400 metres) on the island of La
Palma, Spain.
It took seven years to construct!
Activities
1. Galileo Galilei invented the telescope. Why was this such an important
discovery? What did astronomers know about the stars before then?
2. Research. Have you heard of the Hubble telescope? When was it built?
Where is it? What pictures does it take?
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UNIT
1
The Universe
What do you remember?
• What are the points of light in this photo?
• What is the difference between …
– a star and a planet?
– a moon and a comet?
Content objectives
Key language
In this unit, you will …
Describing
• Learn about the characteristics of the
Universe
Planets are spherical bodies which orbit the Sun.
Asteroids are rocky objects which are irregular in shape.
• Calculate astronomical sizes and distances
Comparing
• Analyse the components of the Universe
Dwarf planets are smaller than planets.
The Earth is larger than Mercury.
• Compare sizes: the Sun and the planets
• Create a constellation poster
8
Giving instructions
Study the constellations.
Research more about them on the Internet.
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1. What is the Universe like?
Scientists developed two different theories to explain what
the Universe was like.
Activities
1. Find ten words in the word search.
M P
I
L A N E T S
G R
L A A S A
L U A T S R P T
K N E
• Geocentric theory
nd
2 century BC: Ptolomy
proposed that the Earth was
the centre of the Universe.
That is, the Sun, Moon and
planets orbited the Earth.
• Heliocentric theory
In 1542, Nicolas
Copernicus proposed
that the Sun was at the
centre of the Universe.
In 1610, Galileo Galilei invented the telescope, and proved the
Heliocentric theory: the planets and stars revolve around the Sun.
L
T T A E
Y S E N A H C
L
W O H B R X E
L
A T M S U N Y
I
Y M O O N L
G T
K E S W C P A E
2. Imagine an alien friend from
another galaxy wants to write to
you. Write your galactic address.
What makes up the Universe?
The Universe is all the matter, energy and space that exists.
The Universe is made up of galaxies which contain stars. Stars can have planetary systems
made up of planets and satellites. Galaxies are separated by vast spaces.
Galaxies are a vast collection of stars, dust and gases, held together by the
gravitational attraction between the components. They appear in groups called
galaxy clusters. Scientists think the vast spaces between the galaxies are empty.
Our galaxy, the Milky Way, belongs to the Local Group galaxy cluster.
Stars form when clouds of gases are pulled together by gravitational forces. They
are so hot inside that they emit heat and light. A galaxy can have up to five hundred
thousand million stars. An enormous cloud of gas and dust, a nebula, surrounds
the stars.
Planets are bodies which orbit some stars. They do not emit light; they receive light
from the star. They make up planetary systems. Our planetary system is the Solar
System. It is made up of eight planets and one star, the Sun, as well as moons,
comets and asteroids. The Solar System is located on a spiral arm of the Milky Way.
Natural satellites orbit some planets. The Earth’s natural satellite is the Moon.
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2. How big is the Universe?
The Earth seems huge, but, in reality, it is small
compared to the Sun. The Sun is only one
of the millions of stars in the Milky Way.
To imagine the size of the Universe,
use these comparisons with everyday objects.
Activities
3. Express the distance of Mercury, Mars and Pluto
from the Sun in kilometres.
• Imagine the Sun is the size of a pea.
• The closest star is another pea, five hundred
and forty kilometres away from the first pea.
• The Earth is like a particle of dust situated
two metres away from the first pea.
• The Milky Way contains one hundred thousand
million peas which form a circle with a radius
of seven million kilometres.
What units of measurement
do astronomers use?
Mars
Mercury
Pluto
4. Research the term light-year. Why is it used in
astronomy?
Did you know that...?
• Astronomical unit (AU). This is the distance
from the Earth to the Sun. Approximately
150 million kilometres. Compare the distance
of these planets from the Sun:
– Mercury: 0.4 AU
– Mars: 1.5 AU
– Pluto: 39.4 AU
• Light-year. This is the distance light travels in
one year. Light travels 300,000 km
in one second or
9.5 trillion km
in one year.
10
Source of light
Time to reach
the Earth
the Sun
8 mins. 20 sec
Centauri, the
nearest star
4 light-years
Betelgeuse
500 light-years
The radius of the Sun is 109 times
greater than the radius of the Earth.
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3. What makes up the Solar System?
The Solar System was formed approximately
five thousand million years ago from the gas and
dust of a nebula.
Our Solar System is made up of the Sun, eight
planets with their satellites, dwarf planets and
small solar system bodies. The Sun is the central
body.
• The Sun consists mainly of two gases:
hydrogen and helium. It is the closest star
to Earth.
• Planets are spherical bodies which revolve
around the Sun. They all move in elliptical
orbits, held by the gravitational force of the
Sun. Planets are much larger than other
celestial bodies which orbit the Sun.
Mercury, Venus, Earth and Mars are made up
mainly of rock. Jupiter, Saturn, Uranus and
Neptune are made up mainly of gases.
The planets in the Solar System
Planet
Distance from
Sun (AU)
Period of
rotation
Period of
revolution
Mercury
0.39
58.65 days
88 days
Venus
0.72
243 days
224.6 days
Earth
1.00
23 h 56 mins
365.25 days
Mars
1.52
24 h 37 mins
1.88 years
Jupiter
5.20
9 h 55 mins
11.86 years
Saturn
9.54
10 h 40 mins
29.46 years
Uranus
19.19
17 h 14 mins
84.07 years
Neptune
30.06
16 h 7 mins
164.82 years
Activities
5. Which planet …
•
•
•
•
• Dwarf planets are spherical bodies which orbit
the Sun. They are smaller than planets.
• Small solar system bodies are other celestial
bodies which orbit the Sun. They include
asteroids, comets and satellites. Satellites
orbit planets and consist of rock.
takes the longest to orbit the Sun?
is the fastest to orbit the sun?
has the longest days?
has the shortest days?
6. Why is a “day” on Venus longer than its “year”?
7. What is an orbit?
8. What do you call the imaginary plane of the
Earth’s orbit?
How do the planets move?
Celestial bodies like the Earth, have two types of movement:
Rotation. Celestial bodies spin or rotate
on an invisible axis. This invisible line is
called the rotational axis.
Revolution. Celestial
bodies revolve around
other celestial bodies.
Orbit. A curved path which
a celestial body follows in its
revolution around another celestial
body. The orbit of the Earth
around the Sun is an ellipse.
ecliptic plane
rotational axis of
the Moon
rotational axis
terre
strial
orbit
lunar orbit
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Mercury
Diameter: 4,880 km
Venus
Diameter: 12,104 km
Earth
Diameter: 12,740 km
Mars
Diameter: 6,794 km
4. Which are the inner planets?
The inner planets are the four planets closest to the Sun: Mercury, Venus, the Earth and Mars.
The Earth is the only planet that has life on it. The other
planets are too hot or too cold.
In 2004, the robots Spirit and Opportunity landed on
Mars. They investigated the possible existence of water.
INNER PLANETS
Did you know that...?
Pluto, Ceres and Eris are
dwarf planets. Pluto used to
be considered a planet. In
2006, the International Union
of Astronomers reclassified it
as a dwarf planet.
Terrestrial or rocky planets: the crust and mantle are
made of rock. The core is metallic
Mercury
Venus
Earth
Mars
Diameter (Earth = 1)
0.382
0.949
1
0.532
Diameter (km)
4,880
12,104
12,740
6,794
⫺180 to 430 ºC
465 ºC
⫺89 to 58 ºC
⫺82 to 0 ºC
none
CO2
N2+O2
CO2
0
0
1
2
no
no
no
no
the smallest
and closest to
the Sun
rotates in
opposite
direction
the only
planet
with life
very thin
atmosphere
Average surface
temperature (ºC)
Atmosphere
Satellites
Rings
Interesting
characteristics
Ceres
CO2 ⫽ carbon dioxide
12
N2 ⫹ O2 = nitrogen⫹ oxygen
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Uranus
Diameter: 51,118 km
Saturn
Diameter: 120,536 km
Jupiter
Diameter: 142,984 km
5. Which are the outer planets?
Jupiter, Saturn, Uranus and Neptune are the four outer planets.
They are called gas giants because they consist mainly of gases.
Neptune
Diameter: 49,492 km
Saturn’s rings are made up of small particles, mostly ice.
OUTER PLANETS
Activities
Gas giants: they consist mainly of gases
9. Which planet …
Jupiter
Saturn
Uranus
Neptune
11.209
9.44
4.007
3.883
142,984
120,536
51,118
49,492
⫺150 ºC
⫺170 ºC
⫺200 ºC
⫺210 ºC
H2⫹He
H2⫹He
H2⫹He
H2⫹He
63
59
27
13
yes
yes
yes
yes
largest planet,
most satellites
system of rings
rotational axis is
almost horizontal
greatest distance
from the Sun
• has the most satellites?
• is closest to the Sun?
• supports life?
H2 ⫽ hydrogen
• is the largest in the
Solar System?
• spins on its axis in the
opposite direction?
10. If you live on Venus, will
the Sun rise in the East
and set in the West?
He ⫽ helium
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Pluto
Mercury
Mars
Earth
comet
Neptune
Saturn
Jupiter
Venus
Uranus
Asteroid belt
The Solar System. Observe the elliptic paths of the planets’ orbits around the Sun. Notice that the orbit of Pluto, a dwarf planet,
is more inclined.
6. What are small Solar System bodies?
There are two main types: asteroids and comets. They orbit the Sun.
• Asteroids are rocky objects which are irregular in shape. They can
be several hundred kilometres in diameter, but most are only
a few metres wide. Asteroids orbit around the Sun. Most of them
are between the orbits of Mars and Jupiter. This area is called
the asteroid belt.
• Comets are small bodies that travel around the Sun in highly
elliptical orbits. They are irregular in shape. The nucleus is made
up of a mass of ice, dust and gas. When comets travel close
to the Sun, some of the ice evaporates, creating the long,
bright tails of the comets.
Activities
11. Compare the main characteristics of the inner and outer planets.
12. Describe an inner or outer planet. Your partner will identify it.
14
This inner planet
This outer planet
is smaller / larger than
is the largest / smallest.
has (no)
the Earth.
… satellites.
The atmosphere
is made up of
carbon dioxide.
helium.
…
Halley’s comet has a bright tail. It was
named after the English scientist
Edmund Halley. He was the first
scientist to calculate the orbit of this
comet. Halley’s comet will next be
visible from Earth in 2061.
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Hands on
Prepare a constellation poster
Constellations are imaginary patterns of bright stars.
All societies have invented constellations. The
Ancient Greeks invented the constellations we call
the twelve signs of the zodiac.
There are 88 official constellations. However, most
of them do not really look like the mythical figures
they represent.
The night sky looks different in the Northern and
Southern Hemispheres. The position of the
constellations changes with the seasons because
of the movement of the Earth.
Cassiopeia
Orion
Ursa major
Gemini
1. Study these constellations. Which ones can you
see in the night sky where you live?
The constellation Orion
2. Choose one of the constellations and make a
poster.
a. Find more information in encyclopedias or on
the Internet.
b. Draw the constellation, or cut out a drawing
or a photo of it.
c. Write some sentences about the constellation.
Orion represents the hunter.
The three stars in the middle are his belt.
His sword hangs from his belt.
You can see his sword and his bow.
Activities
13. Look up the constellation for your sign
of the zodiac.
14. Choose another constellation.
Research more about it on the Internet.
a. Find out where and when it is most clearly
visible in the sky. Is it in the Northern or the
Southern Hemisphere?
b. Write the dates associated with this sign.
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Activities
21. Talk about astronomical distances with a partner.
15. Label each diagram with the name of …
How far away is … from …?
It is … km / … light-years away.
a. a theory of the universe
b. the person who proposed the theory.
b
a
Astronomic distances from the Earth
Object
16. Make a drawing of the Solar System and label it: the
Sun, the inner planets, the outer planets, Pluto and
the asteroid belt.
17. Make a timetable of your daily activities on these
planets. Give an approximate duration for each.
• Earth. Rotation: 24 hours
• Mercury. Rotation: 58.65 Earth days
• Jupiter. Rotation: 9.841 Earth hours
Distance
space station
300 km
weather satellite
36,000 km
the Moon
384,000 km
the Sun
150,000,000 km
Pluto
6,000,000,000 km
Alpha Centauri
4 light-years
22. Research the latest astronomic discoveries. Report
your findings to the class.
23. This drawing shows the positions of a comet
in orbit.
When a comet gets close to the Sun, why does it
develop a tail? Why does an asteroid not?
Duration on …
Activities
Earth
Mercury
Jupiter
18. What two types of movement do all planets have?
Describe them.
19. Describe the composition, temperature and
movement of the Sun.
20. Make an illustrated list of the planets. Write them in
order: start with the closest one to the Sun.
a
b
c
24. Draw a diagram of the Solar System seen from
above. Include the rotation and revolution
movements of each planet.
25. Copy and complete to situate the Moon in the
Universe:
The Moon is a satellite of … which belongs to the
planetary system called … . The star of this planetary
systems is … . It belongs to a galaxy called … .
This galaxy is part of the galaxy cluster called … .
d
e
f
16
g
h
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THE UNIVERSE
What should you know?
1
Early
concepts
• Geocentric theory: the Earth is the centre of the
Universe. The Sun, Moon, stars and planets revolve
around the Earth.
• Heliocentric theory: the Sun is the centre of the
Universe. The Earth, planets and stars revolve
around the Sun.
Components
• Galaxies are grouped together in galaxy clusters.
• Galaxies contain thousands of millions of stars.
• Stars are massive spherical bodies of gases. Some
stars have planetary systems with planets,
satellites, asteroids and comets.
Units of
measurement
• Astronomical unit (AU): the distance between the Earth and the Sun, about
150 million kilometres.
• Light-year. The distance that light travels in one year: about 9.5 trillion kilometres.
The Solar
System
The Solar System is the planetary system of our Sun.
It consists of:
• The Sun: a medium-sized star in the Milky Way galaxy.
• Planets:
Inner: Mercury, Venus, Earth and Mars.
All are rocky.
Outer: Jupiter, Saturn, Uranus, and Neptune. All are gaseous.
• Dwarf planets: Pluto, Ceres, Eris
• Natural satellites: celestial bodies which revolve around planets and dwarf planets.
• Small Solar System bodies
Asteroids: small rocky bodies which orbit the Sun. Some form belts. The asteroid
belt: a band of asteroids between the orbits of Mars and Jupiter. Comets: masses of
ice and rock found beyond the orbit of Pluto.
Projects
INVESTIGATE: Could Mars support life?
First, list the factors that make life possible on Earth.
Then, investigate this website: http//solarsystem.nasa.gov/planets/profile.cfm?Object=Mars
WEB TASK: Do you want to visit Mercury, Jupiter or Mars?
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UNIT
2
Planet Earth
What do you remember?
• In this photo, what does each colour correspond to?
• Is the Earth an outer or an inner planet?
• What is the interior of the Earth like?
• Where does life exist on Earth: in the geosphere or the biosphere?
Content objectives
Key language
In this unit you will …
Describing
• Learn about the Earth’s characteristics
Water exists in three states.
It takes 28 days to orbit the Earth.
• Identify lunar phases
• Describe the geosphere
• Learn about the Earth’s “spheres”
• Reproduce conditions of solar and lunar
eclipses
18
Expressing cause and result
This causes the sequence of day and night.
This makes the seasons occur.
Comparing
The days get shorter.
Ocean trenches are the deepest areas.
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1. What is the Earth like?
The Earth is special for many reasons. The Earth is
the only planet with:
• an atmosphere containing oxygen
1. Draw a diagram of the Earth, as seen from
space. Draw two people: one at the North Pole
and one at the South Pole.
• an average temperature of 15ºC
• a water cycle
• life as we know it
All these characteristics make the Earth a unique
planet in the Solar System.
• The atmosphere consists of a mixture of gases.
Nitrogen and oxygen are the most abundant.
Oxygen is essential for plant and animal
respiration. There is also carbon dioxide,
essential for photosynthesis.
• The average temperature is 15°C on the
Earth’s surface. This is possible because of the
distance from the Sun and the composition of
the atmosphere.
• Water exists in three states (ice, liquid, water
vapour) due to temperature variations. These
variations make the water cycle possible.
Photo of the Earth and the Moon taken by satellite.
Activities
2. Find out the mixture of gases and the average
temperatures of Venus and Mars. Why do you
think life is only possible on Earth?
• The Earth has a relatively large natural
satellite, the Moon. The gravitational attraction
of the Moon causes ocean tides.
• The Earth’s magnetic field protects living
beings from dangerous solar radiations.
• Conditions exist for life. Thousands of millions
of years of evolution have produced the variety
of species there are today. This includes
humans.
• There is considerable geological activity on the
Earth: earthquakes, volcanoes, mountain
building, erosion, etc.
Volcanoes are proof of intense geological activity.
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2. How does the Earth move?
direction of rotation
The Earth moves in two different ways:
Equator
• Rotation: The Earth rotates on a slightly tilted
axis, always in the same direction. This
rotation causes the sequence of day and night.
North Pole
plane
of the Earth’s
orbit
Sun’s rays
• Revolution: The Earth’s revolution around the
Sun is an ellipse. It takes 365 1⁄4 days to
complete the revolution. This is one year.
Northern
Hemisphere
Summer
Solar rays strike perpendicular to the Earth’s
surface and produce more heat.
D
ay
rotational axis
23.5°
ht
Nig
South Pole
Southern
Hemisphere
The rotation of the Earth. It is day on the half of the Earth facing
the Sun. It is night on the half facing away from the Sun.
What causes the seasons on Earth?
Winter
Two factors combine to cause the seasons:
• the revolution of the Earth around the Sun
• the Earth’s axis is tilted at an angle of about 23.5º
Solar rays strike the Earth at a
steeper angle and produce less heat.
The tilt of the axis causes differences in temperature
and in the duration of day and night.
The Sun’s rays strike the Earth in different ways
depending on the seasons.
The tilt of the axis makes the seasons occur at
different times of the year in the Northern and
Southern Hemispheres.
Spring. The days get longer and the
nights get shorter until 21st June the longest day.
Spring equinox
21st March
Winter. The days get longer and the
nights get shorter. On 21st March,
day and night are the same length.
Winter
solstice
21st December
Summer
solstice
21st June
Summer. The days get shorter and the
nights get longer. On 22nd September
day and night are the same length.
Autumn
equinox
22nd September
Autumn. The days get shorter
and the nights get longer until 22nd
December- the shortest day.
The seasons in the Northern Hemisphere
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3. How does the Moon move?
The Moon moves in two different ways:
1
• Rotation. The Moon takes 29.5 days to
rotate once on its axis: a “lunar day”.
8
• Revolution. The Moon takes about
twenty-eight days (twenty-seven days
and eight hours) to orbit the Earth once.
2
7
3
A “lunar month” is the period of time
between two new moons. It is about 29.5 days.
A “lunar day” is as long as a “lunar month”.
As a result, the same side of the Moon always
faces the Earth.
6
4
5
The same side of the Moon always faces the Earth. The red dot
indicates the dark or hidden side. It is never visible from Earth.
Activities
3. Draw a diagram to show the phase of the
Moon in the Northern Hemisphere today.
4. When is there a New Moon?
5. Draw a diagram of the phases of the
Moon in the Southern Hemisphere.
The phases of the Moon
New Moon
Last Quarter
The Moon is between the Sun and the
Earth, so the Moon is not visible.
The dark side (not illuminated) faces the
Earth. The Moon rises and sets with the
Sun, but you cannot see it from Earth.
Half the side is lit by the Sun. The
illuminated part slowly shrinks. It rises
at midnight and sets at noon.
First Quarter
Full Moon
Half the side is lit by the Sun.
The illuminated part slowly increases.
It rises at noon
and sets at midnight.
When the Earth is between the Moon
and the Sun, the entire Moon is visible.
The illuminated side faces the Earth.
It rises and sets with the Sun.
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Hands on
Reproducing eclipses
If the Moon passes between the Sun and the Earth, and blocks
off the sunlight, a solar eclipse occurs.
If the Moon passes behind the Earth, so the Earth prevents sunlight
from reaching the Moon, a lunar eclipse occurs.
Materials
the Sun
the Moon
the Earth
1. Reproduce a solar eclipse. Position the planets: the Moon should block the Sun’s light
and project a shadow on the Earth.
2. Reproduce a lunar eclipse. Position the planets: the Earth should block the Sun’s
light and project a shadow on the Moon. Remember: a lunar eclipse can only take place
during a full moon.
3. In your notebooks, copy the diagrams for both eclipses.
umbra
penumbra
penumbra
Earth
Moon
Sun
Sun
Moon
Earth
Solar eclipse
Activities
6. Find out when the next solar and lunar eclipses will
take place.
Visit this site:
http://sunearth.gsfc.nasa.gov/eclipse/eclipse.html
7. How must you protect your eyes when observing a
solar eclipse?
22
umbra
Lunar eclipse
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4. How many “spheres” make up the Earth?
The Earth is the only known planet which contains water and living things.
It is made up of four interrelated parts or “spheres”. These are:
• The geosphere. The solid part which includes
the crust, mantle and core. The upper 100 km
of the geosphere is called the lithosphere:
it is the most rigid part.
• The atmosphere. The air: a layer of gases which
envelops the Earth.
• The hydrosphere. All the water on the Earth.
• The biosphere. All the living things which
inhabit the Earth.
The geosphere
The geosphere consists of three concentric layers: the crust,
mantle and core. The crust and the upper mantle make up
the lithosphere.
The crust is the outer layer of
rock. The most abundant
minerals are silicates.
• The continental crust
makes up the
continents. Granite
is the most
common rock.
• The oceanic
crust makes up
the ocean floor.
It was created
by intense
volcanic activity
at mid-oceanic
ridges. Basalt, a
volcanic rock, is the
most common rock.
mantle
outer
core
(liquid)
inner
core
(solid)
The mantle is the middle layer,
below the crust. It lies
2,900 km below the
surface. It is made up
of mostly solid rock
material. The
temperature is
higher here, from
1,000ºC to
4,000ºC, so
some areas are
melted rock.
The core is the
centre of the
Earth, below the
mantle. It is made
up mainly of iron.
The temperature is
over 4,000°C. The outer
core is liquid. The inner
core is solid.
Activity
continental crust
(thickness varies from 7 to 70 km)
oceanic crust
(thickness varies
from 7 to 10 km)
8. Show the three layers of the
geosphere in a diagram. Label each
layer: main components,
temperature and state: solid or liquid.
Label the two types of crust.
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5. What is the surface of the Earth like?
From outer space, the Earth looks blue because of
the vast expanses of water on its surface.
The distribution of materials that make up the
Earth’s crust form the different types of land relief.
Ocean floor relief features
• The average depth is 4,500 m.
• The main relief features are:
– Oceanic (mid-oceanic) ridges. Chains
of submarine mountains with intense
volcanic activity. Example: the Mid-Atlantic
ridge.
– Oceanic trenches. The deepest areas
of the ocean. Example: Mariana Trench:
11,034 m deep.
– Abyssal plains. The largest plains on the
planet: 4,000 or 4,500 m deep.
– Submarine volcanoes may create volcanic
archipelagos. Examples: the Canary Islands,
the islands of Hawaii.
Continental relief features
• The average altitude is 600 m.
• The three main relief features are:
– Mountain ranges. Chains of high mountains.
Examples: the Himalayas in Asia or the Andes
in South America.
– Great plains. Large extensions of flat land.
Examples: the Amazon plain in South
America or the Sahara desert in Africa.
– Continental shelves. The areas near the
coastline, under the sea, that are made of
continental crust, not oceanic crust. These
areas slope down from the coastline to a few
kilometres out to sea, to a depth of about
200 metres.
Oceanic relief forms can rise up to 2 km
from the ocean floor. In some places they
appear above the water to form islands.
Example: Iceland.
Cross-section of the Earth’s surface
mountain range
continental great plain
submarine volcano
mid-oceanic ridge
continental shelf
abyss
abyssal plain
24
oceanic trench
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6. What are the other three Earth “spheres”?
Apart from the geosphere, the other three Earth “spheres”
or systems are the atmosphere, the hydrosphere and the
biosphere.
The atmosphere
The atmosphere is the layer of air which surrounds the Earth.
Air is a mixture of gases. The main components are: nitrogen
(78 %) and oxygen (21 %). Oxygen is one of the necessary
conditions for life. There are also small quantities of carbon
dioxide (CO2) and other gases.
Activities
9. Say a relief feature. Your partner
says if it is continental or ocean
floor.
10. Which continental feature is under
the sea?
11. Describe the four different spheres
that make up the Earth. List
examples of features in each
sphere.
The hydrosphere
The hydrosphere is all the water on, under and above
the Earth.
The hydrosphere is made up almost exclusively of liquid
water, but also snow and ice. Other materials in the
hydrosphere are the mineral salts in water. Sea water is very
rich in mineral salts, but fresh water has few salts.
The biosphere
The biosphere includes all the living things which inhabit
the Earth. Living things influence the physical and chemical
changes in the Earth. For example:
• In the Earth’s crust: Animals live in the ground and plants
take mineral salts from the soil. Plant roots can break up
rocks.
• In the atmosphere: Microorganisms which live in the soil
produce nitrogen. Oxygen is produced during
photosynthesis by plants, algae and some bacteria. Many
living things cause evaporation.
• In the hydrosphere: Living things contain water. Plants
take water from the ground. Many organisms live in aquatic
environments.
Did you know that...?
The water cycle refers to how water
evaporates, rises, condenses, falls
to the Earth as rain or snow and
moves around.
This cycle was described 2,500 years
ago byThales.
Coral produces
exoskeletons which
accumulate to form a
rocky shelf.
This atolon in Tahiti is
made up of living
things.
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Activities
12. Draw the Earth. Include an arrow pointing in the
direction in which it revolves. When does the Sun
rise where you live?
18. The Moon has a dark side because each time
it completes a turn around the Earth, it rotates
on its own axis. This takes 28 days.
13. Draw the Earth and its orbit. Show four positions.
With a partner, demonstrate the movement
of the Moon around the Earth.
a. Indicate the solstices and the equinoxes. Divide
the orbit into four parts: one for each season in
the Northern Hemisphere.
b. Colour each season a different colour. Tip:
summer begins with the summer solstice and
ends with the spring equinox.
14. Why is the Sun higher over the horizon at noon
in summer than in winter? Does this occur
at the same time of year in both hemispheres?
15. Think about the seasons. Use this information:
Solstices. summer / winter
Equinox. spring / autumn. The Sun is above
the Equator. Day and night are the same length.
a. When it is summer in the Southern Hemisphere,
what season is it in the Northern Hemisphere?
And when is it spring there?
b. What causes this difference in the seasons?
19. What are the main differences between
the continental crust and the oceanic crust?
20. Match each phrase to: geosphere, hydrosphere,
atmosphere or biosphere.
• water in a river
• waves in the sea
• sand on a beach
• fish, birds, plants or other living things
• the air you breathe
• clouds
21. Two friends are collecting rocks. Who is right? Why?
Girl: These rocks belong to the geosphere.
Boy: No, they belong to the lithosphere.
22. Think about the Earth’s rotation and answer.
a. Why are days longer in the summer?
16. Match each picture of the Moon with a number
in the diagram below.
A
B
C
D
E
F
G
H
1
8
7
2
6
3
5
4
17. The ecliptic is an imaginary plane. It passes through
the centre of the Earth and the centre of the Sun.
a. Does it go through the centre of the Moon?
b. Does it pass through only sometimes?
How often? When?
26
b. Why do days and nights last for six months
at the poles?
c. How are day and night produced? Make a drawing
to show this.
23. Identify: summer solstice, winter solstice. Explain
your answer.
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2
•
•
•
•
It has an intense magnetic field.
The atmosphere contains mainly nitrogen, oxygen and carbon dioxide.
The average temperature is 15ºC.
Water exists on Earth in solid, liquid and gaseous states. There is a
water cycle.
• The Earth has one large natural satellite, the Moon.
• Life exists on Earth.
The Moon, the Earth’s
satellite
• Rotation. The Earth rotates on its axis. The axis is tilted 23.5º. This
rotation creates day and night.
• Revolution. The Earth revolves around the Sun. Its orbit is elliptical.
These two movements and the Earth’s tilt cause the seasons. Other
consequences are the differences in the length of day and night.
The Moon takes almost 28 days to orbit the Earth. It takes the same length
of time to rotate once on its axis.
Lunar phases: New Moon, First Quarter, Full Moon and Last Quarter.
• Solar eclipse: the Moon blocks the light from the Sun.
• Lunar eclipse: the Earth blocks the light from the Sun so it does not
reach the Moon.
The gravitational attraction or “pull” of the Moon on the oceans causes the tides.
The four Earth “spheres”
THE EARTH
Movements
Special characteristics
of Earth
What should you know?
Geosphere: the solid part of the Earth. It consist of the:
• Lithosphere: the crust and the upper mantle.
– Continental crust: makes up the continents.
– Oceanic crust: makes up the ocean floor. The Earth’s surface is made
up of continental features and ocean floor features.
• Mantle: the middle layer of the Earth, made of rock.
• Core: the centre of the Earth, made up of metals. Outer core: liquid. Inner
core: solid.
Atmosphere: the layer of air which surrounds the Earth. It consists of a
mixture of gases.
Hydrosphere: all the waters on the Earth.
Biosphere: the part of the Earth where living things exist. Living things can
be aquatic or terrestrial.
Projects
EXPERIMENT: Think about the geosphere.
• Shake together a mixture of gravel, cork and water. Allow this to settle. Observe the separation in layers by density.
• Compare with the diagram of the geosphere on page 23. Identify the crust, mantle and core represented
in your experiment.
WEB TASK: Find out about artificial satellites.
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All creatures great and small
The Earth is the only planet we know which is capable of supporting life.
1. How many living creatures can you find?
2. Check your answer in the word snake.
fr
e
og
le p
ha n t f lo
we
ra
nt
bu
tte
r f lymon
y
ke
tre
3. Now put them into three different groups. Explain why you chose them.
28
o
em
s s f e r n f ungi
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eyepiece
tube
Look at these drops of water from
the pond. Can you see anything in
them? Some living things are so
small they cannot be seen with the
naked eye. They can only be seen
through a microscope.
nosepiece
arm
objective
lenses
coarse
focusing
knob
cover slip
stage
4. Match each task, a-f, to its
corresponding part of the
microscope.
iris
diaphram
fine
focusing
knob
a. This magnifies the specimen
b. This increases the amount of
light
base
light source
c. This is where you put the
specimen
Optical microscope
d. This is where you look through
e. This is where you change the
magnification
f. This is used for fine focusing
5. Look at the pond water through the microscope. What a surprise!
Use the code to write the vowels and discover the names of the microorganisms. Code: A__ E__ I__ O__ U__
__ __GL__N__
PR__T__Z__ __
B__CT__R__ __
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UNIT
3
Living things
What do you remember?
• Can you name any of these living things?
• Classify them into groups: plants, animals, vertebrates, invertebrates.
• What do all living things do?
• What is the animal kingdom?
• What kingdom do human beings belong to?
Content objectives
Key language
In this unit, you will …
Expressing facts
• Define the characteristics of living things
• Describe cell structure and cell functions
• Classify unicellular and multicellular living things
• Classify living things into five kingdoms
• Make slides to study cells
30
Living things feed, reproduce and interact.
Making impersonal statements
Cells are organised into levels.
Expressing purpose
Photosynthesis enables plants to obtain energy.
Water is used to transport substances.
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1. What is biodiversity?
Biodiversity is the variety of life on Earth in all its
forms. Biodiversity is the result of a slow process
called evolution. Evolution began with the first
life forms and still continues today. Species change,
and adapt to the environment.
Scientists believe there may be more than thirty
million species. Approximately two million species
have been classified.
What factors can reduce biodiversity?
Biodiversity varies tremendously throughout the
world. It is influenced by climate zones and
habitats. For example, more than half the world’s
species live in tropical rain forests and coral reefs.
Some countries have many different climate zones
and habitats. As a result, they have more biological
diversity. For example, Spain has more biological
diversity than other European countries.
3
Whole species of living things become extinct
every day for these four factors:
1
Destruction
of habitats
caused by
deforestation,
the construction
of roads,
dams, etc.
2
Did you know that...?
Rain forests
have the
greatest
biodiversity.
Uncontrolled
hunting and
fishing
endangers
many species:
for example the
Iberian lynx
(Lynx pardinus)
is in danger of
extinction.
Pollution of water, soil and the atmosphere, caused
by agricultural, industrial and urban development.
4
Introduction of
exotic species
can destroy
local species.
For example,
the river crab.
Activities
1. True or false? Biodiversity refers to all living things.
2. Why does biodiversity vary throughout the world?
3. Match each photo with a factor that reduces
biodiversity.
a. pollution
b. destruction of habitats
c. uncontrolled hunting
d. introduction of exotic species
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2. What do all living things have in common?
All living things have a similar chemical
composition.
All living things also carry out three functions:
nutrition, interaction with the environment and
reproduction.
Nutrition refers to all the processes which enable
living things to obtain the energy and matter they
need to live.
Living things can be classified into two groups
depending on how they feed.
• Autotrophs produce the organic substances
which they need from inorganic substances.
They take substances like water, mineral salts
and carbon dioxide from the soil and the
atmosphere. To obtain these substances,
autotrophs need energy. They get energy from
sunlight through a process called
photosynthesis. Chlorophyl enables them to do
this. Plants, algae and some bacteria are
autotrophs.
• Heterotrophs feed on organic matter which is
already elaborated: for example, living things or
their remains. Animals, fungi, some bacteria and
all protozoa are heterotrophs.
Interaction with the environment: all the
processes which enable living things to react to
changes in their environment. For example: plants
grow towards the light; animals flee from
predators.
Reproduction: refers to all the processes which
enable living things to create new living things.
There are two basic types:
• Asexual reproduction involves one living
thing. For example: a sponge can produce buds
which give rise to new sponges.
• Sexual reproduction involves living things of
different sexes. Each one provides a sex cell or
gamete. The two sex cells join to form the first
cell of a new living thing, the zygote.
32
What function is this cheetah carrying out?
Why are all the flowers following the Sun? What function are
they carrying out?
Activities
4. Complete:
Heterotrophs feed on ... .
Autotrophs obtain ... .
Sexual reproduction involves ... .
Asexual reproduction involves ... .
5. Test your partner. Ask questions:
Which processes enable living things to ...
... create new living things?
... adapt to their environment?
... obtain the energy they need?
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3. What are living things made up of?
All living things are made up of chemical substances. Carbon (C), oxygen (O),
hydrogen (H), and nitrogen (N) make up about 95 % of all living matter.
Combinations of these elements form molecules of living matter called
biomolecules.
Living things are made up of two kinds of substances: inorganic and organic.
Inorganic substances
Inorganic substances do not contain carbon. They
are present in living things and non-living things.
The principle inorganic substances are:
• Mineral salts have various functions: they make
up different structures, like shells, bones and
teeth. They are present in internal fluids, like
tears, sweat and blood.
• Water is the most abundant substance in living
things. Living things obtain water directly
by drinking it, or indirectly from substances
that contain water. Plants obtain water
from the environment. Water is necessary for
chemical reactions and to transport all other
substances.
Organic substances
Organic substances are unique to living things. Carbon is their
principal element. Organic substances present in living things are:
Biomolecules
Glucides
Example
Use/Function
glucose
cellulose
Lipids
fatty acids
cholesterol
Proteins
haemoglobin
antibodies
keratin
Nucleic
acid
DNA
RNA
Activities
to provide energy
to make structures
to provide energy
to make structures
to transport oxygen
to fight microorganisms that cause disease
to make structures: hair, nails
to control cell function and heredity
Organic and inorganic substances are present in different amounts in
plants and animals.
Plants
Animals
water 60 %
water 74 %
lipids
0.8 %
mineral
salts 3.2 %
proteins
3.2 %
glucides
19 %
lipids
20 %
glucides
0.6 %
mineral
salts 3.4 %
proteins
16 %
6. Compare organic and
inorganic substances:
… substances are …;
… substances have …
7. Ask questions about
organic and inorganic
substances. For example:
How are (lipids) used by
living things?
They are used to …
8. Use the pie charts to
calculate, in grams, the
approximate value of each
group of biomolecules:
a. Weigh yourself, then
calculate the
biomolecules in your
body.
For example,
100 kgs = 60 kg water
b. a sunflower: 2.250 grams.
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4. What are cells?
Cells are the smallest unit of life. They are the structural
and functional units for all living things.
• All living things are made up of one or more cells.
• Cells carry out the functions of nutrition, interaction
with their environment and reproduction.
• Most cells are very small. For example, skin cells
are approximately one hundredth of a millimetre
in size.
• All cells come from other cells.
Did you know that...?
Robert Hooke
was the first
person to use
the term cells.
In 1665, with this
microscope, he
observed cavities
in a thin slice of
cork, and called
them cells.
What are the two basic types of cells?
nucleus
cytoplasm
cytoplasm
organelles
organelles
genetic
material
cell
membrane
cell
membrane
Eukaryotic cell
Prokaryotic cell
• Prokaryotic cells have no nucleus. They have
no nuclear membrane. Genetic material is
dispersed throughout the cytoplasm. They are
simpler and smaller than eukaryotic cells.
Bacteria are made up of prokaryotic cells.
• Eukaryotic cells have a nucleus, separated
from the cytoplasm by the nuclear membrane.
Algae, protozoa, fungi, animals and plants have
eukaryotic cells.
How is a cell organised?
• The cell membrane covers the whole cell.
• Cytoplasm is the inside of the cell. It is a jelly-like
substance. Many of the chemical reactions of the cell
take place here. Organelles are small structures in the
cytoplasm. They are responsible for respiration, making
and storing nutrients, etc.
• Genetic material controls and regulates how cells
work. This DNA contains the hereditary information
that is passed from one cell to the daughter cell. DNA
makes up the chromosomes.
34
Activity
9. Read the chart, then make sentences
to describe the cells: Eukaryotic cells are
found in animals.
Eukaryotic
cells
Prokaryotic
cells
found in
animals
bacteria
size
big
small
nucleus
yes
no
complexity
complex
simple
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5. How do animal and plant cells differ?
Both animals and plants have eukaryotic cells,
but there are some differences.
• Plant cells have a rigid cell wall which
surrounds the plasmatic membrane. The cell
wall gives the cell its shape and strengthens it.
• Plant cells are usually polyhedral, but animal
cells are various shapes: round, square, star-like.
• Plant cells have unique organelles called
chloroplasts which are responsible for
photosynthesis.
• The nucleus of plant cells is usually found on
one side. A vacuole takes up most of the space.
Animal cells also have vacuoles, but they are
smaller.
Plant cell
Animal cell
Cell membrane. Like a
skin around the cell. It
keeps the cell together
and controls what passes
in and out.
Nucleus. Contains
genetic material.
Cytoplasm.
Contains
the organelles:
mitochondria,
vacuoles…
Vacuoles.
Like bags, surrounded
by membranes where
substances, mainly
water, accumulate.
Mitochondria.
Where energy
is obtained from
nutrients.
Cell wall.
A thick, rigid wall
made of cellulose.
Chloroplasts.
These store a green
pigment,
chlorophyll,
which absorbs
the Sun’s energy
to elaborate
organic matter
during photosynthesis.
Activities
10. Make a Venn diagram: show the similarities and differences
between animal and plant cells.
11. Draw and label an animal cell with all its parts.
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Hands on
Making a hypothesis. Using a microscope to study cells
A hypothesis is a proposal. It is used as a basis
for reasoning. Scientists use experiments and
observation to test the validity of a hypothesis.
Hypotheses show the relationship between two
or more facts. For example: we know that cell walls
in plant cells are made of cellulose.
Cellulose is a rigid substance that holds the cell
parts together in a polyhedral shape.
Resulting hypothesis: If you observe cells through
a microscope that are polyhedral in shape and joined
together by thick walls, you know they are plant cells.
Making a specimen of plant cells
1
1. Take a moss plant specimen and use tweezers to remove
a phyllode.
2. Place the phyllode on a slide. Add a drop of water.
3. Place the cover slip on the specimen, look through
the microscope and draw the specimen.
Use different magnifications.
At higher magnifications you may be able
to see and count the chloroplasts.
2
3
phyllodes
Making a specimen of animal cells
1. To obtain cells, rub the inside of your cheek gently with
1
2
a clean cotton bud.
2. Spread the cells on a slide and add a drop of water.
3. Stain the cells with methyl green or a similar dye.
4. Put the cover slip on, look through the
3
microscope and draw the specimen.
4
Check your hypothesis
Notice that the plant cells have a polyhedral shape.
The animal cells are irregular, and they are not joined together.
Activities
12. Label each plant cell indicating its magnification.
13. Imagine that your hypothesis were incorrect. What result would make this obvious?
14. Imagine you have an unidentified sample. Hypothesis: If this is a living thing, it will be made up of cells.
Is this hypothesis correct? Can you use it to differentiate between living and non-living things?
What would you do to classify the sample as living or non-living?
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6. How do living things differ?
Living things can be classified into two different
groups: unicellular and multicellular.
• Unicellular living things have only one cell.
They sometimes form colonies. Unicellular living
things feed, interact with the environment and
reproduce. Example: paramecia.
• Multicellular living things have many different
cells. Example: plants and animals.
Multicellular organisation
Activities
15. Describe one of the specialised cells.
Your partner identifies it. For example:
A: It has no nucleus. B: A red blood cell.
16. What is the difference between tissues, organs
and systems?
Example: ... are made up of...
muscle cell
Cells
Cells in multicellular living things are organised
in levels. The cells work together to carry out
the vital functions.
• Cells are specialised: they have specific
functions. Each type has a unique shape and
structure.
• Tissues are groups of cells with the same
function. Example: muscle cells form muscle
tissue.
• Organs are groups of various tissues which act
together. Example: a muscle is an organ made
up of muscle tissue, nerve tissue, connective
tissue and blood tissue.
• Systems are made up of several organs.
Example: the digestive system includes the
stomach, the intestines, etc.
Tissue
muscle
tissue
Organ
muscle
Muscular
system
muscular
system
Form and function of cells
Specialised Cells
Sperm cells
Red blood cells
Neuron or Nerve cells
Root hair cells
have a tail (flagellum)
so they can swim
toward the ovum
consist mainly of
haemoglobin to
transport oxygen
are like wires with
a lot of extensions
so they can conduct
and capture messages
are long and thin so they can
absorb water and mineral
salts from the soil
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7. What are the five kingdoms?
Scientists use criteria for classification to organise living things into groups.
Classification enables them to compare different living things.
Scientist classify all living things into five kingdoms by three main criteria:
type of cells, how the cells are grouped, and nutrition.
Monera Kingdom
Protoctist Kingdom
Contains unicellular, prokaryotic
organisms. They may be autotrophic or
heterotrophic.
Bacteria and cyanobacteria.
Contains unicellular and multicellular
living things. They are all eukaryotes.
They have no tissues. They may be
autotrophic or heterotrophic.
Protozoa, algae.
Plant Kingdom
17. Copy and complete the
table to describe
the five kingdoms.
Kingdom
Moneran
Type of cells
Contains multicellular eukaryotes. They have tissues. They
are heterotrophic.
Animals: may be invertebrate or vertebrate.
Tissues
No tissues
Eukaryotic
Heterotrophic
Plant
Animal
38
Autotrophic / Heterotrophic
Prokaryotic
Protoctist
Fungi
Contains unicellular and multicellular
living things. They are eukaryotes.
They have no tissues. They are
heterotrophic.
Yeasts, moulds, mushrooms.
Animal Kingdom
Contains multicellular eukaryotes. They have tissues.
They are autotrophic.
Mosses, ferns, flowering plants.
Activity
Fungi Kingdom
They have tissues
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8. How are living things classified?
Living things can
be differentiated
by the way they feed,
reproduce, interact
with their enviroment,
etc. They are classified
into different groups.
The main group is the
kingdom. Each
kingdom is then
divided into
subgroups.
CLASSIFICATION
YOU
BECAUSE YOU...
Kingdom
Animal
Are a heterotroph, cells form tissues
Phylum
Chordate
Have a spinal chord
Sub phylum
Veterbrate
Are a chordate with a backbone
Class
Mammal
Have warm blood; babies drink mother’s milk
Order
Primate
Your thumbs and fingers work together
Family
Hominid
Walk upright
Genus
Homo
Talk, have a long childhood
Species
Homo sapiens
Are intelligent, have little body hair ...
This is how you are
classified.
9. What is a species?
A species is the first level of classification for living things. A species
is a set of living things which are physically similar. They reproduce
and usually have fertile descendants.
Animals from the same species have similar appearances.
However, there can be differences in structure, size and colouring
between the male and the female. This difference is called
dimorphism.
Activities
18. Make a list of animals that
show sexual dimorphism.
19. Describe the differences
between the male and
female of some animals.
donkey
female
horse - mare
mule
The lion and lioness are examples
of dimorphism.
A male peacock uses its colourful tail
to attract the female.
When a donkey and a mare mate, the
result is a mule. Mules are sterile
because donkeys (Equus asinus), and
horses (Equus caballus) belong to
different species.
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Activities
20. Study the illustrations. Which represent living
things? Which characteristics support your
decision?
A
A
D
C
B
25. Study the cell diagrams. Match each with
a name and description.
G
F
E
H
B
21. Classify these living things as autotrophic or
heterotrophic.
C
A
B
C
D
E
F
22. Copy and complete the chart.
Biomolecule
Function
Glucides
Proteins
23. Draw an animal cell with the most important
organelles. What structures would transform it into
a typical plant cell? Draw them.
Include: mitochondria, cytoplasm, cell membrane
24. Test your classmates. Ask questions about the five
kingdoms.
40
1. They are long and thin in order to absorb water
and mineral salts from the soil.
2. They are shaped like wires with a lot of
extensions. They conduct messages around
the body.
Lipids
Which
kingdoms
D
are made up of
have
autotrophs / eukaryotes?
no tissues?
unicellular and multicellar
living things?
3. They have a tale (flagellum) which enables them
to swim towards the ovum.
4. They have no nucleus so they have room to
transport oxygen in the haemoglobin.
– Sperm cell
– Neuron
– Red blood cell
– Root hair cell
26. Complete the table on sexual dimorphism.
Animal
Group
Male
Female
lion
mammal
long mane
no mane
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What should you know?
Common
characteristics
of living
things
LIVING THINGS
Composition
Cells
Classification
and
biodiversity
•
•
•
•
3
They are born and they die.
They have a similar chemical composition.
They are made up of cells.
They have three vital functions: nutrition, interaction with
the environment, and reproduction.
They are made up of two kinds of substances:
• Inorganic substances. Not exclusive to living things: water
and mineral salts.
• Organic substances. Exclusive to living things: glucides,
lipids, proteins and nucleic acids.
Cells consist of:
• A plasmatic membrane which surrounds the cell.
• Cytoplasm or internal matter. It contains the organelles
(mitochondria, chloroplasts, etc.).
• Genetic material. This controls cell functions.
There are various kinds of cells:
• Prokaryotic. With no nucleus and no nuclear membrane.
• Eukaryotic. With a nucleus and a nuclear membrane.
Animal and plant eukaryotic cells are different.
Living things may be:
• Unicellular. Consisting of one cell.
• Multicellular. Consisting of many cells forming tissues,
organs and systems.
Living things are classified into kingdom, phylum,
subphylum, class, order, family, genus and species.
There are five kingdoms:
• Monera Kingdom: unicellular, prokaryotic living things.
They may be autotrophic or heterotrophic.
• Protoctist Kingdom: unicellular and multicellular living
things. They are eukaryotes and have no tissues. They may
be autotrophic or heterotrophic.
• Fungi Kingdom: unicellular and multicellular beings. They
are eukaryotes and have no tissues. They are heterotrophic.
• Plant Kingdom: multicellular eukaryotes. They have tissues
and they are autotrophic.
• Animal Kingdom: multicellular eukaryotes. They have
tissues and they are heterotrophic.
Projects
INVESTIGATE: an organisation trying to save the biodiversity of the planet. Give examples of actions taken.
WEB TASK: Learn how you can protect the biodiversity.
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UNIT
4
Invertebrates
What do you remember?
• What characteristics make the giant squid an invertebrate?
• Do you know any invertebrates with …
– a soft, porous body?
– an elongated body with rings?
– a soft body covered by a shell?
– an external skeleton?
The giant squid is the largest
known invertebrate: 20 m
long, 1,000 kg. Its tentacles
are more than 15 m long.
It lives deep in the ocean:
400 to 1,500 m below the surface.
Content objectives
Key language
In this unit, you will …
Making generalisations
• Recognise the main characteristics of
invertebrates
Most sponges live in the sea.
Some molluscs have no shell.
• Classify invertebrates into groups
Making impersonal statements
• Describe invertebrate life functions
Their bodies are divided into segments.
They are made up of one or two valves.
• Make a model of an invertebrate that can float
• Differentiate between bilateral and radial
symmetry
42
Did you know that...?
Expressing contrast
Some are carnivores, but others are herbivores.
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1. What makes up the animal kingdom?
The animal kingdom is made up of multicellular,
eukaryotic organisms. They are heterotrophic and
sensitive to their environment.
How are animals classified?
Animals are classified in two groups:
• Invertebrates. Animals with no backbone. Some,
like worms or jellyfish, have no skeleton. Others,
like insects or spiders, have an external skeleton or
exoskeleton.
• Vertebrates. Animals with a backbone which is part of
their internal skeleton or endoskeleton.
Activities
1. What part of a sponge body does the
name porifera refer to?
2. Copy the drawing of the sponge. Use
arrows to label the flow of water. Show
the entry points and the exit point.
3. Talk about cnidaria.
Which
are
have
can
tentacles?
carnivorous?
radial symmetry?
an opening at the top?
a body like a tube?
float?
The simplest invertebrates
The simplest invertebrate animals are classified into two
groups: porifera and cnidaria. Porifera and cnidaria have
no organs.
water exits
osculum
water
enters
Porifera
Sponges belong to this group. Most live in the sea. Their
bodies are full of pores and channels, so water circulates
in and out of them. They feed by filtration. Water enters
though the central cavity, deposits nutrients, and leaves
through a hole called the osculum. Sponges do not move
around; they are attached to rocks or coral.
Cnidaria
There are three different groups of cnidaria: jellyfish, corals
and sea anemones. Their main characteristics are:
• radial symmetry.
• a soft body, with only one opening, the mouth, which is
surrounded by tentacles.
• a gastrovascular cavity, something like a stomach,
connected to the mouth.
• Nutrition. Cnidaria are carnivorous: they use their
tentacles to capture prey.
• Interaction. Most cnidaria live in the sea. Jellyfish can
float; corals and sea anemones live fixed to the sea bed.
• Reproduction. In their lifetime, cnidaria usually pass
through both the polyp and the medusa stages:
Polyps reproduce asexually by budding.
Jellyfish (medusae) reproduce sexually: there are male
and female specimens.
channels
pores
Cross-section of a porifera
tentacles
polyp
jellyfish
Cnidaria
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2. How do these worms differ?
These worms have bilateral
symmetry,
a soft body, and no
skeleton.
Annelid bodies are divided
into segments. Each
segment has a cavity called
a coelom.
Nematodes have no segments.
The most common types of
worms are:
PLATYHELMINTHES
ANNELIDS
BODY
BODY
Long, flat, soft. In tapeworms the body
is divided into rings. No legs.
No respiratory or digestive system.
Soft, cylindrical body divided into
segments. Each segment is similar and
has the same organs. These repeated
segments are called metameres. Tiny
appendages on each segment enable
movement.
Annelids breathe through gills.
Exception: earthworms breathe through
the skin.
clitellum
NEMATODES
segments
BODY
Soft, cylindrical bodies.
No segments or rings.
No respiratory system.
The Taenia tapeworm is a parasite that
lives in human intestines. It absorbs
nutrients directly from its host. Some
Taenia species are more than ten
metres long.
HABITAT
HABITAT
Water or soil.
Some are parasites.
Water or damp places.
Many are parasites.
head
Earthworm
digestive tube
body wall
coelom
setae or hairs
REPRODUCTION
REPRODUCTION
Heterosexual:
There are male and
females specimens.
Hermaphrodites: They have both male
and female sex organs.
Platyhelminthes can fertilise themselves.
Cross-section of segment with coelom cavity
HABITAT
Water. Some are parasites, for example,
leeches.
Activities
4. Make your own table.
Annelids
Main
characteristics
5. Which groups do the animals in
the photos belong to?
6. Talk about these worms.
Habitat
Which
Example
44
in water?
are
hermaphrodites?
breathe
through gills?
live
parasites?
REPRODUCTION
Some annelids are hermaphrodites.
Earthworms have larger segments
called clitellum where the eggs are
deposited.
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3. What are molluscs?
Squid, mussels, oysters, slugs and snails are all common molluscs.
Most are aquatic: they live in the sea or in fresh water. Garden snails,
however, live in damp soil.
What is a mollusc body like?
shell
stomach
Molluscs have these main characteristics:
• bilateral symmetry
• a soft body divided into three parts:
– head which contains sensorial organs
and the mouth
– body mass with the main organs
– muscular foot to move about
• The body is covered by a fine membrane,
the mantle. This produces a protective shell.
The shell is made up of one or two valves.
Some species, such as octopi and slugs, have
no shell. Others, such as cuttlefish and squid,
have an internal shell.
body mass
lung
eyes
head
mouth
foot
Garden snail
Mollusc functions
• Respiration. Aquatic molluscs breathe through gills.
Terrestrial molluscs breathe through lungs.
• Nutrition. Some are carnivores. Others are herbivores.
• Reproduction. Most are hermaphrodite and
oviparous. The larva hatches, goes through
metamorphosis and produces an adult individual.
How many groups are there?
There are three main groups:
• Gastropods: snails, sea snails and slugs. They have a spiral-shaped
shell with a single valve. Exception: slugs have no shell.
• Bivalves: clams, cockles and mussels. Their shells have two valves.
• Cephalopods: squid, cuttlefish and octopi. They have tentacles,
but no shell.
Gastropods: slug
Bivalves: mussel
Activities
7. Make your own table for
molluscs. Use page 44 as a
model.
8. Match the photos to the
words.
no shell – eyes – foot –
garden snail – bivalve –
mouth – spiral shell
Cephalopods: squid
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4. What are arthropods?
Arthropods are the largest, most varied group of living things:
more than one million species. They live in sea water, fresh
water and on land.
thorax
head
antennae
What is an arthropod body like?
The main characteristics of arthropod bodies are:
• a segmented body covered by a thick cuticle that acts
like an external skeleton or exoskeleton.
• a body divided into three parts: head, thorax and
abdomen.
In some arthropods, the head and thorax are joined to
form a cephalothorax. The antennae, eyes and mouth
are in the head. The sensorial organs are welldeveloped. The eyes can be simple: ocelli, or
compound.
• bilateral symmetry
• jointed appendages: legs, antennae, wings in insects.
The number of legs varies.
wings
abdomen
compound eye
mouth
legs
Wasp
Arthropod functions
• Nutrition. Arthropods can be carnivorous, herbivorous
or scavengers.
• Respiration. They breathe through trachea (terrestrial
arthropods) or gills (aquatic arthropods).
• Reproduction. Most have male and female sexes which
are distinguishable. They are oviparous. Fertilisation is
internal. Some hatch as larvae and undergo metamorphosis.
As they grow, arthropods shed the old exoskeleton and
grow a new one. This is called moulting. Moulting takes
place various times throughout an arthropod’s lifetime. In
other words, arthropod growth is discontinuous.
Activities
9. Make your own table for
arthropods: see page 44.
10. Make generalisations about
arthropods. Use pages 46 - 7.
Some are ... . Most are ... .
Some have ... , but others ... .
METAMORPHOSIS OF A MONARCH BUTTERFLY
1
2
3
1 The female lays eggs. A larva, called a caterpillar, hatches. 2 After a short period of development, the caterpillar
changes into a pupa (chrysalis stage). 3 After more changes, the chrysalis breaks open and the butterfly comes out.
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How many groups are there?
Groups
Examples
Body / Appendages
Habitat
Crustaceans
lobster, crab
usually 10 legs
aquatic
Myriapods
centipede, scolopendra
worm-like body, many legs
terrestrial
Arachnids
spider, scorpion
8 legs
terrestrial
Insects
butterfly, ant, bee, wasp
6 legs, 2 antennae, 2 or 4 or no wings
terrestrial, some aquatic
Crustacean. Lobster. The front legs have claws for defence.
Myriapod. Scolopendras are fast-moving, venomous
and predatory.
abdomen
cephalothorax
legs
pedipalp
chelicerae
Arachnid. Spider. The cephalothorax has two chelicerae
which help the spider eat, and two pedipalps for defence.
Spiders have four pairs of legs: eight in all.
Insect. Ants have a strong mouth for chewing and six legs.
Did you know that...?
In some cultures, insects are food. You might find these
insects in an Indonesian restaurant: fried dragonflies.
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5. What are echinoderms?
Echinoderms live on the sea bed. Some live fixed
to a surface, but others move slowly about. Examples:
sea urchins, starfish and sea cucumbers.
arm
What is the body like?
The main characteristics of echinoderms are:
• radial symmetry in adults, bilateral symmetry
in larvae.
• body shape: rounded (sea urchin), cylindrical
(sea cucumber) or like a star (starfish).
• an internal skeleton made up of plaques.
• no separate head, but there is a mouth on the
underside.
ambulacral
apparatus
Starfish
ambulacral
feet
Echinoderm functions
• Movement. The ambulacral apparatus, a series
of internal tubes filled with water, enables
movement. The tubes form ambulacral feet with
suckers.
• Respiration. Most echinoderms breathe through
their skin, using the ambulacral apparatus. Some
have simple gills.
• Nutrition. They are carnivorous and feed mainly
on small crustaceans and molluscs.
• Reproduction. Most echinoderms have male
and female sexes, but some are hermaphrodite.
Fertilisation is external. The larvae can swim and
undergo metamorphosis to change into adults.
Did you know that...?
Starfish can regenerate body parts
or a whole body. All they need is a
single leg with part of the central
disc.
Activities
11. Can you trace the radial symmetry
on the photos?
12. Make your own table for echinoderms:
see page 44.
13. How does a starfish feel? And a sea
urchin?
How many groups are there?
Echinoedea:
sea urchins
48
Stelleroidea:
starfish
Crinoidea:
sea lilies
Holothuroidea:
sea cucumbers
Ophiuroidea:
ophiura
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Hands on
Carrying out an experiment
The exoskeleton of an insect is covered with a fine layer
of grease or wax. This makes it impermeable. The wax
protects insects which live in water, such as the skater
(Gerris lacustris). The skater floats on the water surface.
If its legs get wet, it cannot take off.
Skaters can walk on water without sinking.
Compare the performance of insects
with or without impermeable legs
1. Make two identical insect models from card
as in the photograph.
Body: a rectangle 4 x 6 cm
Legs: 5 cm long
Fold the ends of the legs so the insects
can stand.
2. Melt wax from a candle. Cover the bottom of the legs
of only one insect with the wax.
Observe and record the data
3. Place both insects on the surface of the water.
Observe carefully, and record your data on a chart
like this one. Initially, after two minutes, then after
10 minutes.
It stands on its legs.
It floats initially.
Model
with wax
It floats after
2 minutes.
Model
without
wax
It floats after
10 minutes.
Insect without
waxed legs
Insect with
waxed legs
Interpret the results
4. Does the wax make the paper model impermeable?
Activities
14. What would happen to an insect with no wax on its legs? It would float / sink.
15. RESEARCH: Spiders can walk on their webs without sticking. Can you explain this?
Think about the experiment above.
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Activities
16. The nautilus lives in a spiral-shaped shell. Inside,
the shell is divided into compartments. The animal
lives in the largest one. The other compartments
are filled with gas, so the shell floats.
20. Identify the photos: annelid or caterpillar.
Compare them. The... has, but the... has...
a
a. What group of molluscs does the nautilus belong
to? Explain.
b. What is the main difference between a nautilus
and an octopus?
The animal lives in
this compartment
b
Nautilus
17. Copy and label the cnidaria: tentacles, opening,
can float, live fixed.
21. Read and label: Tapeworms can be 4 metres long.
The bulge in the front of the body is called the head
or scolex. It has four suckers and pointed hooks. The
thin part below it is called the neck. There are many
rings which get bigger as they get older and move
farther from the head.
Label the drawing: head, suckers, hooks, neck,
rings.
18. Which group of invertebrates does each animal
belong to?
a
e
c
b
f
d
g
h
22. Name each group of molluscs.
a
b
c
d
19. Study the drawing of the starfish.
a. Copy, then label the following parts: arms,
ambulacral apparatus, ambulacral feet.
b. What do starfish eat?
What body mechanisms
do they use to eat?
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What should you know?
4
Porifera
• The body resembles a sack full of pores and channels. Water circulates
through it.
• Porifera live attached to a surface. They feed by filtration.
INVERTEBRATES
Cnidaria
• They have a soft body and a mouth surrounded by tentacles. There are two
body types: polyps which live attached to a surface, alone or in colonies, and
jellyfish which float in the sea.
• They are carnivorous.
Worms
• They have a soft body and no skeleton.
• The main groups are:
– Platyhelminthes: long, flat, soft bodies.
– Nematodes: soft, cylindrical bodies, not divided into segments
– Annelids: soft, cylindrical body divided into segments
Molluscs
• They have a soft body divided into three parts: head, body mass and foot.
Many have a shell.
• They breathe through gills (aquatic species) or through lungs (terrestrial
species).
• They go through metamorphosis.
Arthropods
• They have jointed legs and an external skeleton. Their bodies are divided into
three parts: head, thorax and abdomen.
• They breathe through trachea (terrestrial arthropods) or gills (aquatic
arthropods).
• They change their outer covering (moult), and some undergo metamorphosis.
Echinoderms
• They have an internal skeleton made up of plaques under their skin.
• They breathe through their skin, using the ambulacral apparatus. Some
echinoderms have simple gills. All are carnivorous.
• They undergo metamorphosis.
Projects
RESEARCH: Find out what crustaceans local fish markets sell. Make a list.
WEB TASK: Find out what some spiders eat.
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UNIT
5
Vertebrates
What do you remember?
• What is common to all animals?
• What are the three vital functions of all living things?
• What are the two main groups of animals?
How do they differ?
• How many groups of vertebrates are there?
Content objectives
Key language
In this unit, you will …
Expressing purpose
• Learn basic characteristics of animals
Aquatic amphibians use lungs to breathe.
• Compare vertebrates and invertebrates
Expressing cause and results
• Recognise the vital functions of
vertebrates
Expressing contrast
• Make a scientific drawing
52
They undergo metamorphosis.
As a result, they lose their gills and develop lungs.
A shark’s skin, however, has denticles.
All reptiles have legs. However, snakes do not.
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1. What characteristics do vertebrates have?
All vertebrates have an endoskeleton with a backbone. The body is
made up of a head, a trunk, and many have a tail. Vertebrates have
articulated limbs, a well-developed nervous system and bilateral
symmetry.
head
brain
spinal
column
trunk
articulated limbs
Penguins have bilateral symmetry.
Horse
Jellyfish
tail
Spider
Activities
1. Study the photos and
classify the animals:
vertebrate or invertebrate.
2. Compare the spider
and the lion: legs, body,
covering...
3. Show the bilateral
symmetry of two animals
with lines.
Lion
Kangaroo
Tortoise
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2. What are mammals like?
head
Most mammals are terrestrial animals. Some are aquatic
animals like dolphins, but only one, the bat, can fly.
hair
spinal column
ears
trunk
Main body parts
tail
• A neck joins the head to the trunk. The tail
is an extension of the spinal column.
• Mammals have four limbs. Terrestrial mammals
have legs, aquatic mammals have fins,
and bats have wings.
• Mammal bodies are covered with hair or fur
which keeps them warm.
• Mammals have teeth. The shape
of the teeth depends on the food
the mammal eats.
• Mammals have many glands. The most important ones
are the mammary glands. These produce milk.
neck
articulated limbs
Alsatian dog
What functions do mammals have?
Activities
• Respiration. They use lungs to breathe. Aquatic mammals come
up to the surface to breathe.
• Nutrition. They feed on different things. For example, carnivores
eat meat. Insectivores eat insects. Herbivores eat plants.
Granivores eat seeds.
• Reproduction. Fertilisation takes place internally, and the young
grow in the mother’s womb. Mammals are viviparous: they give
birth to live young. The babies feed on their mother’s milk.
• Interaction. Mammals are homeothermal or warm-blooded:
they can keep their body temperature constant.
4. Complete the table.
Mammals
Physical
characteristics
Nutrition
Respiration
Reproduction
5. Compare a human being
with another mammal.
Make a Venn diagram.
How do the three groups of mammals differ?
Monotremes. Example: platypus.
Monotremes are born from eggs. They
have a beak, but no teeth.
54
Marsupials. Example: kangaroo.
Marsupials finish their development
inside the mother’s pouch.
Placentals. Example: dolphin. The young
develop inside the mother’s body, in the
uterus.
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3. What are birds like?
wing
barbs
rachis
spinal
column
calamus
Feather
legs
• A bird’s body is aerodynamic: adapted for flight.
The neck is sometimes very long.
• Birds have four limbs: the back limbs are legs,
and the front limbs are wings.
• A bird’s body is covered with feathers.
• Each feather has an axis or rachis. Barbs spread out
on each side of the rachis. The calamus joins the feather
to the body.
• Bird bones are hollow. This makes their body light, so they
can fly more easily.
• Strong wing muscles are attached to the sternum or keel.
• Birds have a horny mandible or beak, but no teeth.
keel
beak
Sea gull
Activities
6. Make your table for birds:
see page 54.
What functions do birds have?
• Respiration. They use lungs to breathe. The lungs are connected
to air sacs which enable them to breathe and to fly.
• Reproduction. Birds are oviparous: they lay eggs. The eggs are
incubated until the chicks hatch. Fertilisation takes place
internally.
• Nutrition. The shape of a bird’s beak depends on the food it eats.
• Interaction. Birds are homeothermal or warm-blooded.
Buzzard. Strong, curved Swallow. Short beak.
beak. It catches its prey It captures insects
and tears the flesh.
in flight.
neck
Heron. Long, pointed
beak. It fishes
in shallow water.
7. What characteristics enable
birds to fly?
8. Associate each beak with
how the bird feeds: opens
seeds, fishes, tears its prey.
a. strong, curved; b. short,
strong; c. long, pointed.
Duck. Wide, flat
beak. It filters water
to obtain food.
Rooster. Strong, short
beak. It feeds on grain
which it has to open.
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4. What are reptiles like?
Most reptiles, like snakes, crocodiles, lizards and
tortoises, are vertebrate terrestial animals, but
some spend a lot of time in the water.
• Reptiles, except snakes, have four limbs
or legs. Snakes have no limbs.
• Reptile bodies are covered with hard scales
to keep them warm. Adult lizards and
snakes shed their skin, but tortoises have
a hard shell called a carapace.
spinal column
skin with scales
What functions do reptiles have?
• Interaction. Reptiles are poikilotherms,
or cold-blooded. As a result, they cannot
regulate their body temperature. Reptiles
are warm or cold depending on the
environment.
• Respiration. Reptiles use lungs to breathe.
• Nutrition. Most reptiles are carnivores. They
have teeth to capture their prey. Turtles,
however, have beaks. Many snakes
have fangs connected to glands that produce
poison.
• Reproduction. Reptiles are oviparous. The
eggs develop inside a sac filled with liquid,
called amnion. A hard shell protects the eggs
and prevents dehydration. Unlike bird eggs,
reptile eggs are not incubated. Some snakes
are ovoviviparous, that is, the embryo
develops inside an egg that remains inside
the female until hatching.
legs
Green iguana
Activities
9. Make your table for
reptiles: see page 54.
10. What is a carapace like?
How does it protect the
tortoise?
How many groups of reptiles are there?
snake
Snakes. Cobras, vipers,
boas and snakes
56
chameleon
Lizards. Lizards, iguanas,
chameleons
tortoise
Turtles. Tortoises and fresh
water turtles
crocodile
Crocodilians. Alligators
and crocodiles
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5. What are amphibians like?
All amphibians begin life in water, and they always live
in wet places. However, the adults are vertebrate terrestrial
animals, like frogs, toads, newts and salamanders.
• Amphibians have four limbs or legs.
Frogs have very strong back legs.
• Amphibian skin is moist and has no covering.
Some amphibians have glands that produce toxins.
• Amphibians are the only vertebrates that undergo
metamorphosis. As a result, the adults
do not look like the young.
tail
moist skin
spinal
column
Tiger
salamander
legs
THE METAMORPHOSIS OF A FROG
1
2
The female lays eggs
in the water and the male
fertilises them.
3
4
The tail and gills
A tadpole with gills and
disappear. Legs develop.
a tail emerges from the
egg and lives in the water.
The adult frog is a
terrestrial animal with
lungs and four legs.
What functions do amphibians have?
• Interaction. Amphibians are cold-blooded. As a result, they
do not usually live in cold places.
• Respiration. Adult reptiles use their lungs and skin to breathe.
Young frogs, or tadpoles, are aquatic and use gills to breathe.
• Nutrition. Most amphibians are carnivores, but at the tadpole
stage, they are herbivores.
• Reproduction. Most amphibians are oviparous,
but salamanders are ovoviviparous. Fertilisation takes place
externally in some amphibians and internally in others.
Did you know that...?
Some South
American tribes
use secretions
from poisonous
frogs to make
poison darts.
Activities
11. Test your classmates. Complete the text to ask
questions.
Example: What do tadpoles use to breathe?
12. Show the life cycle of a frog with drawings.
13. Compare frogs and tadpoles in a chart.
14. Make your table for amphibians: see page 54.
What do ...
use to
breathe?
keep moist?
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6. What are fish like?
scales
dorsal fin
Fish are aquatic vertebrates. Some live in fresh
water and some in salt water.
• Fish are fusiform: the body
is wider in the middle than
at the ends.
• Fish limbs are called fins.
Each species of fish has different
fins, but most have dorsal, pelvic
and caudal fins.
• Fish are covered with scales.
A shark’s skin, however, is covered
with small denticles.
• The lateral line system is a sensory organ
that detects vibrations.
lateral line system
caudal
fin
anal
fin
spinal column
operculum
pelvic fin
What functions do fish have?
• Interaction. Fish are cold-blooded. As a result, they cannot
regulate their body temperature.
• Respiration. Fish use gills to obtain oxygen from water.
The gills are protected by the operculum or cover. However,
sharks and rays have no operculum.
• Nutrition. Most fish are carnivores.
• Reproduction. Fish are oviparous, and fertilisation
takes place externally. However, sharks are ovoviviparous;
fertilisation takes place internally.
Activities
15. Make your table for fish: see
page 54.
16. Which type of fin enables fish
to move forward most?
Did you know that...?
Many fish have a swim
bladder which fills with air
to control buoyancy.
How many groups of fish are there?
There are two groups of fish: cartilaginous and bony.
ray
Cartilaginous fish, such as sharks or rays.
The skeleton is made of cartilage.
58
carp
Bony fish, such as carp, hake or salmon.
The skeleton is made of bone.
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Hands on
Scientific diagrams
Scientific diagrams often depict living things.
A scientific diagram does not have to be a perfect
work of art, but it must...
• be realistic.
• have the correct proportions.
• have realistic colours (if it is coloured).
• be labelled.
Follow these steps to make a diagram of a fish.
1. Put the fish on a tray.
Be sure you can see the parts you want to draw.
2. Observe the shape and size.
3. Fill in the outline with the other parts of the
fish: fins, operculum, eye, scales…
First, draw the outline and the main elements:
fins, tail…
head
lateral line
dorsal fin
caudal fin
eye
operculum
4. Colour the drawing.
pectoral fin
pelvic fin
5. Label all the parts.
Observe the model carefully. Use the correct
colours.
Activities
17. Study the scales on a fish. Make a scientific drawing of their shape and position.
18. Touch a fish from the caudal fin to the head. What does it feel like?
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Activities
19. Which of these are characteristic of animals?
a.
b.
c.
d.
25. Copy the diagram, and label the parts of a feather.
They have eukaryotic cells.
They are heterotrophic.
They have an internal skeleton.
They have four limbs.
b.
a.
20. What are the characteristics of vertebrates?
21. Do all animals have bilateral symmetry?
c.
26. Reptiles are poikilotherms. What does this mean?
a. Is this kind of symmetry also internal?
b. Are there any vertebrates with no bilateral
symmetry?
27. Bats are the only mammals that can fly. Compare
bat wings and bird wings. What similarities and
differences are there?
22. The blue whale lives in the sea, and spends a lot of
time beneath the water.
a. Why do whales have to come to the surface?
b. Why don’t marine mammals have ears?
28. The photographs show a fish, a mammal
and a bird. What characteristics enable them
to live in water?
a
23. What kind of bird eats each type of food?
I. Meat
II. Insects in the water
A
B
III. Grain
IV. Insects in wood
C
D
b
24. Write a table and complete it with the
characteristics of each vertebrate group.
Vertical: Mammals, Birds, Reptiles, Amphibians, Fish
Horizontal: Type of limb, Skin covering, Homeotherm/
Poikilotherm, Respiration, Nutrition, Reproduction
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c
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What should you know?
ANIMALS
Mammals
VERTEBRATES
Birds
Reptiles
Amphibians
Fish
5
• Animals are multicellular, eukaryotic, and have specialised cells.
• They are heterotrophic. They are sensitive to their environment, and they can move.
• There are two main types of animals:
– Invertebrates have no backbone.
– Vertebrates have a backbone.
There are five groups: mammals, birds, reptiles, amphibians and fish.
• Mammals have limbs. Terrestrial mammals have legs;
aquatic mammals have fins; bats have wings.
• Mammals bodies are covered with hair or fur. Mammals are
homeothermal. They use their lungs to breathe. They are
viviparous. They have mammary glands. Mammals feed on
different things.
• Birds are aerodynamic. The back limbs are legs,
and the front limbs are wings. A bird’s body
is covered with feathers. Its bones are hollow.
Birds have a beak.
• Birds are homeothermal. They use their lungs to breathe.
They are oviparous. Birds feed on different things.
• All reptiles, except snakes, have four legs. Reptile bodies
are covered with hard scales.
• Reptiles are poikilothermal. They use their lungs to breathe.
Most reptiles are oviparous and carnivorous.
• Amphibians have four legs. Amphibian skin is moist, and
has no covering.
• Amphibians are poikilothermal. They use their lungs and
skin to breathe. They undergo metamorphosis. Most are
oviparous. Adult amphibians are carnivores.
• Fish are fusiform. The limbs are called fins. Fish are covered
with scales.
• Fish are poikilotherms. They use their gills to breathe. Most
fish are oviparous. Most fish are carnivores.
Projects
HYPOTHESIS: Feathers keep birds dry. Test this hypothesis. Place some feathers in water; observe them, and
revise your hypothesis.
WEB TASK: Find out if the Iberian lynx makes a good pet.
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UNIT
6
The plant
and fungi kingdoms
What do you remember?
•
•
•
•
•
Which characteristics enable you to classify ferns as plants?
Which characteristics do all plants have?
Name two main differences between plants and animals.
Do all plants reproduce in the same way?
Why are plants and fungi so important in nature?
Content objectives
Key language
In this unit, you will …
Comparing
• Identify the main characteristics of the
plant and fungi kingdoms
Ferns are bigger than mosses.
Conifers are the largest group of gymnosperms.
• Recognise plant and fungi organs, shape
and functions
• Discover how plants and fungi obtain
nutrition and reproduce
• Learn how to make a classification
62
Describing a process
When minerals dissolve in water, raw sap is produced.
Making generalisations
Most gymnosperms are evergreens.
Many angiosperms are deciduous.
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1. What living things make up the plant kingdom?
The plant kingdom is made up of multicellular, eukaryotic,
autotrophic living things. They cannot move about.
All plants:
• have roots, stems and leaves. These vary according to the
species.
• are multicellular: made up of many cells which form tissues.
• have eukaryotic cells. These cells have a nucleus and
organelles surrounded by membranes. They are surrounded
by a cellulose wall. They have chloroplasts which contain
chlorophyll. Chlorophyll is necessary for photosynthesis.
• are autotrophic beings: they can make their own food
through photosynthesis.
• live attached to the soil. However, they are able to make
some movements. For example, they grow towards light.
How are plants classified?
Activity
1. Classify the plants as in the
example.
Are they vascular?
No
Yes
Mosses
Ferns, gymnosperms,
angiosperms
Do they have flowers?
No
Yes
Plants are classified in two groups: non-flowering and flowering.
• Non-flowering plants are simple plants without flowers
or seeds.
– Mosses. They are small, and non-vascular: they have
no conductor vessels.
– Ferns. They are bigger than mosses. They are vascular:
they have conductor vessels to distribute water and
nutrients.
Do they have fruit?
No
Yes
• Flowering plants are more complex, with flowers and seeds.
– Gymnosperms. They have seeds inside a false fruit, like
a pinecone.
– Angiosperms. They have seeds inside a real fruit.
Mosses
Ferns
Gymnosperms: pine
Angiosperms: roses
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2. What are non-flowering plants like?
Mosses and ferns are
non-flowering plants:
• They reproduce by spores. The
mature spores are dispersed by
the wind. The spores germinate
and produce new mosses or
ferns.
• They grow in damp, shady
places. They need a lot of water
in order to reproduce.
capsule
spores
swimming
sperm
fertilisation
a
b
zygote
germinating
spore
mature gametophytes
Life cycle of a moss
Mosses
Ferns
The main characteristics are:
• very small, non-vascular plants.
• no true roots, stems or leaves. They fix
themselves to the ground by rhizoids.
• Instead of leaves, they have small laminas called
phyllodes.
• Mosses produce spores inside capsules at the
end of filaments.
The main characteristics are:
• vascular plants. They can be very large.
• have roots, stems and leaves. The stem, called
a rhizome, grows horizontally in the round.
• The leaves are large, and are called fronds.
• ferns develop clusters of spores called sorus
(plural: sori) on the underside of the fronds.
frond
capsule
filament
root
rhizome
sorus
phyllodes
spores
rhizoid
Moss
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Fern
spores
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3. What are flowering plants like?
There are two main groups: gymnosperms and angiosperms.
Both grow seeds in order to reproduce.
Gymnosperms
Angiosperms
• Most are evergreens, like pine trees and
sequoias. They have leaves all year. The leaves
are normally shaped like needles.
• The seeds are not protected by a fruit.
• They have small, insignificant flowers. These
group together into inflorescences or cones.
These cones are male and female.
• Many are deciduous, for example, oak trees.
They lose their leaves in winter.
• The seeds are enclosed by a fruit. The fruit
protects the seeds. It also enables them to be
dispersed more easily.
• They have brightly coloured flowers. The
flowers attract animals and facilitate polinisation.
male cones contain
the pollen
flowers
leaves
Gymnosperm: pine tree
Angiosperm: oak tree
leaves
The female cones, called
pinecones, contain the seeds,
called pine nuts
Activities
fruit
Did you know that...?
The largest flower belongs
to the species Rafflesia arnoldii.
One flower can reach a diameter
of 1 m and weigh up to 11 kg.
2. Which characteristics differentiate gymnosperms
and angiosperms?
3. Research the plants where you live. Classify them into the four
main groups in a chart. Describe their reproduction, and identify
them as vascular or non-vascular, with cones or with fruits.
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4. What functions do leaves,
stems and roots have?
topside
Plants have three main organs: leaves, stems and roots.
blade
Leaves
Photosynthesis takes place in leaves. The leaves take in
and expel gases from the atmosphere. They eliminate
excess water in the form of water vapour. This process is
called transpiration.
underside
petiole
stomata
apical
bud
The main part of a leaf is called the blade. A leaf has a
topside and an underside. A petiole joins the leaf to the
stem. Gases and water vapour enter the leaf and are
expelled through small pores. These pores, stomata, are
found on the underside of the leaf.
leaves
node
Stems
Plant stems are usually above ground. The stem keeps the
plant upright and supports it. It also carries substances to
other parts of the plant. Some stems, for example, the
potato, accumulate reserves of water and food.
stem
main root
Leaves and branches are joined to the stem at nodes. The
part of the stem between the nodes is called the
internode. Stems grow upwards from the apical bud.
Lateral branches grow out of axilliary buds along the
stem.
secundary
roots
Roots
root
cap
Plant roots have two functions: to fix the plant to the
ground, and absorb water and minerals. Some roots, for
example, carrots and beetroots, accumulate food reserves.
root
hairs
root
cap
The root surface is covered with many tiny hairs
which absorb the water and minerals. Each root ends
in a root cap.
Venus flytrap
66
Did you know that...?
Activities
When the Venus Flytrap plant
detects an insect, its leaves
close quickly to trap the insect
inside.
4. Where do vegetables
come from? Make a poster
showing the vegetables you
eat. Classify them as: leaf,
stem, root, rhizome, etc.
5. Draw a plant. Label
the main parts.
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Hands on
Observation and classification of leaves
What is a classification system?
A classification system is an organised way of grouping
objects into similar categories. Scientists use criteria
(rules) to sort the objects into categories.
Each category in the classification is labelled. An
effective system has multiple levels of increasing detail.
Creating a leaf classification system
not needle
shape
needle shape
Group A
There are an enormous variety of shapes and sizes
of leaves in the plant kingdom.
In pairs or groups, use these steps to create your own
classification system.
parallel
veins
not parallel
veins
1. Collect samples.
Collect as many different samples of leaves as
possible. Remember, pine needles are leaves!
Group B
simple leaves
compound leaves
2. Establish criteria for classifying the samples.
a. Separate the leaf samples into two different
groups. You must use discriminating and
objective criteria so everybody will decide the two
different groups, without personal opinions.
Look at the diagram to help you.
b. Now choose new criteria to separate these
groups into two more groups.
c. Repeat this process again with the new groups,
until all the leaf samples in a particular group
have similar characteristics.
smooth
edge
Group C
not smooth
opposite
edge
arrangement
Group D
Group E
alternate
arrangement
Group F
3. Create a key to explain the classification.
a. Write down your selection criteria. For example: Group A: leaves shaped like needles.
The key can then be used to classify new leaf samples.
b. Test your classification system and key. Ask a classmate to add a new leaf sample to
a group. If this is done correctly, you know your classification works.
Activities
A
6. Using your key, classify leaves A and B, into groups.
7. How might you change your criteria for classification
if you were sorting leaves for a Maths class?
B
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5. How do plants reproduce?
• Asexual reproduction. Only
one plant is involved. When
you take a cutting of a
geranium and replant it,
asexual reproduction takes
place.
• Sexual reproduction. Sexual
cells from two different plants
join together to produce a new
plant. Flowering plants have
sexual reproduction.
Main parts of a flower
Taking a
cutting of a
geranium
plant
Geraniums reproduce asexually from cuttings of stems with leaves
Flowers are the reproductive
organs of angiosperms and
gymnosperms. Flowers have two
parts: the reproductive part and
the protective part.
• Reproductive parts: the stamen
(male reproductive part) and
the pistil (female part).
The ovules are found inside the
ovary. During reproduction,
the ovules come into contact
with the pollen which is
produced in the stamen.
• Protective parts: the petals,
which make up the corolla,
and the sepals, which make up
the calyx.
corolla (petals)
pendule
stigma
pollen
grains
calyx
(sepals)
style
anther
ovary
filament
ovules
Did you know that...?
“Bee” orchids (genus Ophrys)
have flowers which resemble
female bees. When a male
insect lands
on the
flower, the
pollen rubs
on to it, and
the insect
flies off.
68
Stamen
Pistil
Flower
Activities
8. Study the flower diagram on this page. Identify the reproductive
and protective parts of the flower.
9. Research ways that pollen can be carried from flower to flower.
Make a list, and give an example of a plant to illustrate each one.
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The reproductive stages
Plant reproduction has the following stages:
pollination, fertilisation, formation of fruit and
seeds, dispersal and germination.
1. Pollination. Pollen from one flower’s anther
reaches another flower’s stigma.
2. Fertilisation. Pollen reaches the stigma,
penetrates it, and fertilises the ovules inside the
ovary.
3. Fruit and seed formation. The fertilised flower
is transformed. The corolla and the calyx dry up.
The ovary changes into the fruit. The ovules are
transformed into seeds inside the fruit.
4. Dispersal. The ripe fruit falls off the plant or
releases the seeds.
5. Germination. The seeds fall on the ground and
germinate. A small root and shoot grow.
Life cycle of a plant
Wind and animals
transport pollen from
one flower to another
The plant
flowers
A new plant
grows from
each seed
pollen
grain
After
dispersal,
the seed
germinates
seed
pollen
tube
fruit
ovules
Formation
of the seed
and fruit
Fertilisation takes place
inside the ovary
6. Can plants react?
Activities
Plants receive information from the environment, and react to it.
There are two types of reaction:
10. Describe the reproductive
stages of a plant. Refer to
the drawing and text.
• Permanent reactions. These reactions relate to growth. For
example, if you place a plant horizontally, the stem will grow
and curve towards the light. The roots will grow down into
the soil.
In stage 1, pollination …
Where does (fruit and seed
formation) take place?
• Temporary reactions. The plant returns to its initial position
when the change stops. For example, some carnivorous plants
close their leaves when an insect lands on them.
11. Study the plants around
you. Find examples of
permanent reactions.
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sunlight
7. What is plant nutrition?
Plants are autotrophic: they produce their own food.
They use their leaves, stems and roots to carry
out these processes:
carbon
dioxide
• Absorption. Plants absorb water and mineral salts
from the soil through their roots. When mineral
salts dissolve in the water, raw sap is produced.
oxygen
• Transportation. The raw sap travels up
the conductor vessels from the roots
to the stem and leaves.
• Transpiration. Excess water is expelled through
the stomata as water vapour. As a result, raw sap
goes up into the leaves.
water
vapour
elaborated sap
is distributed
raw sap
travels up
• Photosynthesis. Raw sap is transformed
in the leaves into elaborated sap: a mixture
of water and organic substances. It contains
sugars. Sunlight provides the energy needed
for this process. During photosynthesis,
the plant absorbs carbon dioxide through
its leaves. The leaves then expel oxygen
through the stomata.
Finally, the elaborated sap is distributed throughout
the plant cells by the conductor vessels.
Water and mineral salts
• Respiration. Plants breathe. During respiration, plant leaves
take in oxygen from the air and release carbon dioxide.
carbon
dioxide
oxygen
in
F
F
respiration
out
carbon
dioxide
oxygen
in
F
F
respiration
out
Activities
12. Draw a diagram of a plant.
Indicate the phases of
nutrition for each part.
13. Observe these drawings.
a. What does each drawing
represent? Day or night?
b. Do plants breathe and carry
out photosynthesis all day?
Explain your answers.
A
O2
CO2
carbon
dioxide
F photosynthesis
B
CO2
F
Daytime: respiration and photosynthesis
take place simultaneously. Plants
breathe AND carry out photosynthesis.
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O2
oxygen
Nighttime: plants breathe but do NOT
carry out photosynthesis.
O2
CO2
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cap
8. What are fungi like?
Fungi generally grow in the soil in dark,
damp places.
The main characteristics of all fungi are:
• They can be unicellular or
multicellular. However, multicellular
fungi do not produce different types of
tissues.
• The cells are eukaryotic. They have a
true nucleus and a rigid cell wall. They
are similar to plants, but have no
cellulose.
• They are heterotrophic: they do not
produce their own food. There are two
types: saprotrophs and parasites.
– Saprotrophs break down food from
dead, organic materials.
– Parasites feed on other living beings.
They cause diseases in plants and
human beings.
• The body is made up of hyphae which
are microscopic filaments. The hyphae
group together to form the mycelium,
which grows underground.
• Fungi reproduce by spores. When the
spores are dispersed, they form new
hyphae which grow into new fungi.
spores
stalk
mycellium
hyphae
Toadstool
Activities
14. Compare fungi and plants. How are they different?
How are they the same?
15. Talk about fungi:
Which fungi are… …edible? …useful?
…parasites? …multi-cellular? …poisonous?
Three groups of fungi
Fungi can be classified into three main
groups.
Yeasts. Some are parasites. Others are
useful. Yeast is useful for making bread,
beer, wine.
gills
ring
16. Research mushrooms and toadstools. Make a poster.
Moulds. Multicellular. Some are parasites.
Others feed on organic matter and
decompose it: bread mould, fruit mould.
Mushrooms. Multicellular. Some are
edible. Others are poisonous.
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Activities
17. Can a plant move around? And make movements?
Explain your answer, giving examples.
e. Elaborated sap is transported to all parts.
f. Photosynthesis takes place in the cells of the
green parts of the plant.
18. Study the photos and answer.
a. What environments do plants live in?
b. How do they carry out nutrition?
c. Are plants unicellular or multicellular?
A
B
25. Copy and label the flower diagram.
C
26. Compare mosses and ferns. Complete the chart.
Size
Vascular
or nonvascular?
Roots,
stems,
leaves?
Reproduction
Mosses
19. Plants are autotrophic organisms.
Ferns
Can photosynthesis take place in a plant root?
Why or why not?
20. Which part of the plant is each of these foods?
a. cauliflower
d. green bean
b. lettuce
e. artichoke
c. carrot
f. red pepper
21. Imagine the stem from a white carnation is left in a
glass of red ink.
a. After some time, the carnation petals turn red.
Why does this happen?
b. What mechanism allows the liquid to travel up
the stem?
22. If a flowerpot is placed in a window, the stem grows
in the direction of the light. Is this reaction
temporary or permanent?
27. Describe the life cycle of a moss.
28. Why do you think male pine cones are located on
the far ends of the branches?
29. Paper is made with cellulose. To obtain the
cellulose from trees, they are cut down.
a. How could more trees be saved?
b. How can you recycle paper?
c. How else can you save and reuse paper?
30. Look at the tree trunk. There are pairs of rings.
The light area corresponds to springtime, when the
tree grows most. The dark corresponds to autumn,
when it grows less. To find out a tree’s age, count
each pair of light and dark rings.
How old is this tree ?
23. Cacti have very small leaves, like thorns.
What advantage does this have for the plant? What
characteristics of cacti allow them to survive
in the desert?
24. Put the stages of plant nutrition in order.
a.
b.
c.
d.
72
Carbon dioxide enters through the stomata.
The raw sap travels from the root to the leaves.
Oxygen is released and elaborated sap is formed.
The roots absorb water and mineral salts, and raw
sap is formed.
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What should you know?
6
Plants are multicellular, autotrophic living things.
They live fixed to the soil, but can make some movements.
PLANTS
Functions
Non-flowering
plants
FUNGI
Flowering
Plants
• Nutrition. There are five stages: absorption
of nutrients, transportation, transpiration,
photosynthesis and respiration.
• Interaction with environment. Plants can respond
to changes.
• Reproduction. Asexual (only one plant is involved)
and sexual (two different plants are involved).
• Mosses. They are small, non-vascular plants.
They have no true roots stems or leaves.
• Ferns. They are vascular plants. They have roots,
stems and leaves called fronds.
• Gymnosperms. They have seeds, but no fruit.
They have small, insignificant flowers.
• Angiosperms. The seeds are protected by a fruit.
They have colourful flowers.
Leaves. They carry out photosynthesis. Gases are
exchanged and transpiration takes place through
the leaf stomata.
Stems. They keep the plant upright and support the
plant structure.
Roots. They fix the plant in the soil, and absorb water
and mineral salts.
Flowers. They contain the reproductive system.
The main parts are the corolla, calyx, stamen and pistil.
Fungi can be unicellular or multicellular. They have eukaryotic cells.
They are heterotrophic. Fungi are made up of hyphae, which group
together to form the mycelium. Fungi are classified into:
• Yeasts. Unicellular. They are used to make bread, wine, beer…
• Moulds. Multicellular. They grow on food products.
• Mushrooms and toadstools. Multicellular. Some are edible, others are
poisonous.
Projects
INVESTIGATE: How is bread made? How was penicillin discovered? What sort of fungi are involved?
WEB TASK: Where can you find the tallest tree in the world?
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UNIT
7
The simplest
living things
What do you remember?
• What do all living things have in common?
• What three vital functions do all living things carry out?
• What is the chemical composition of all living things?
• Where can you find microorganisms?
Content objectives
Key language
In this unit, you will …
Expressing facts
• Identify the main characteristics
of microorganisms
Parasites feed off living things.
Saprophytes live on decomposing matter.
• Examine the structure and vital functions
of bacteria
Describing
• Learn how viruses are structured
• Observe microorganisms under the
microscope
74
Viruses cannot live independently of their host.
Algae have no true tissues or organs.
Giving instructions
Label each jar. Observe the samples.
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1. What is the Monera kingdom?
flagellum
The Monera kingdom contains unicellular,
microscopic, prokaryotic organisms. They do not have
an organised nucleus.
Bacteria belong to the Monera kingdom. They can live
almost anywhere. They sometimes form colonies, but each
individual cell remains independent. The first living
things on Earth, more than 3,500 million years ago,
were probably bacteria.
genetic
material
cytoplasm
Bacteria nutrition
Most bacteria are heterotrophs: they do not produce
their own food.
bacteria
capsule
• Parasites feed off living things. They cause illnesses
like tuberculosis and cholera.
• Saprophytes live on dead or decomposing matter.
They transform organic substances into inorganic
substances. Some saprophytes are useful: lactobacilo
is used to make yoghurt.
• Symbionts live on the bodies of other living things
to provide mutual benefit. They can be found in the
digestive system of many mammals. There, intestinal
bacteria help with digestion.
Some bacteria are autotrophs. For example, cyanobacteria
make their own food through photosynthesis.
cell wall
plasmatic membrane
Bacteria cell structure
Activities
1. Draw a bacteria cell and label it: cell wall,
cell membrane, cytoplasm.
Bacteria reproduction
2. Compare bacteria. Complete the chart:
Bacteria generally reproduce by binary fission,
producing two daughter cells. Each daughter cell
grows, and then divides again.
Nutrition
Parasites
Saprophytes
Symbionts
How many groups are there?
Bacteria can be classified into four groups by their shape.
Coccus. Spherical
Bacillus. Rod-shaped
Vibrio. Curved-rod shaped
Spirillum. Helical
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2. What is the Protoctist kingdom?
The Protoctist kingdom includes unicellular and multicellular living
things. They are all eukaryotes and have no tissues.
Protozoa and algae are found in this kingdom.
Did you know that...?
Plasmodium, which cause
malaria, need both a
vertebrate and a mosquito to
complete their life cycle.
What are protozoa?
The main characteristics of protozoa are:
• Unicellular. A single cell carries out all the vital functions.
• Heterotrophs. They feed on bacteria, organic remains
and other microscopic organisms.
• They live in both salt water and fresh water. Some protozoa float
on water, zooplankton, and are food for aquatic animals.
• Some are parasites, and cause illnesses.
How many groups are there?
There are four groups of protozoa. They are classified according to
the way they move.
blood
cell
flagellum
cilia
Flagellates
Movement: using a
flagellum or tail.
Nutrition: some are
parasites.
Fact: Trypanosoma causes
sleeping sickness.
76
Ciliates
Movement: using cilia:
hair-like organs.
Nutrition: Some are
parasites.
Fact: Paramecium is shaped
like a slipper. It has two
nuclei.
pseudopods
Rhizopods
Movement: using
pseudopods: projections
of cell cytoplasm.
Nutrition: Some are
parasites, others are not.
Fact: Entamoeba histolytica
causes dystentery.
plasmodium
Sporozoa
No movement.
Nutrition: All are parasites.
Fact: Plasmodium causes
malaria.
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What are algae?
The main characteristics of algae are:
• Unicellular or multi-cellular. Unicellular algae sometimes
form colonies. Each cell can carry out the vital functions.
All the cells of multicellular algae look the same and have
the same functions. Therefore, algae have no true tissues or organs.
• Autotrophs. They contain chlorophyll and other pigments
which capture sunlight for photosynthesis. They can be classified
by their pigment: green, brown or red.
• Some live in salt water and fresh water, but others live on tree
trunks or rocks. Some unicellular algae, like diatomea, float on
water forming phytoplankton, and are food for aquatic animals.
Algae provide food for humans too, for example, ice cream is made
from algae. Industrial uses include medicines and fertilisers.
Diatomea. These unicelular algae have
a silica shell formed by two interlocking
valves.
How many groups are there?
Green algae
Colour: mainly green
Habitat: on the surface of salt water
or fresh water
Example: Euglena, Ulva
Did you know that...?
Brown algae
Colour: green, yellowish pigment
Habitat: salt water, on rocky coasts
and on the surface of water.
Example: Diatomeas, Sargazos
Red algae
Colour: green and red
Habitat: deep in warm, still ocean
water
Example: Coralina
Activities
3. Compare protoctists and monera. Examples:
Many acuatic
animals feed on
zooplankton and
phytoplankton.
Example:
the blue whale
... live in ... . ... are autotrophs, but ... are ... .
4. Describe how each group of protozoa move.
Example: ... move using... . ...do not move.
5. What do algae have in common with plants?
6. Compare protozoa and algae. Draw a Venn
diagram.
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3. What are viruses?
Viruses are not cells, so they are not really living things. They cannot
carry out any vital functions by themselves. They infect living cells,
and then they can reproduce. They are always obligate parasites:
they cannot live independently of their host.
What is a virus like?
The main characteristics
of viruses are:
• Extremely small. They
can only be seen through
an electron microscope.
• Unable to move.
• Extensive habitat. They
are found on the ground,
in the air and in water.
Flu virus seen under an electron microscope
Nucleic acid. Genetic material
inside the capsid
Capsid. A protein shell.
It can have different shapes.
Viral envelope. It covers the capsid. Only some
viruses like influenza or HIV viruses have one.
Virus infection process
1. The virus enters 2. Reproduction: viruses use the infected 3. The viral components 4. New viruses
the cell.
cell to make the viral components.
assemble.
leave the cell.
cell membrane
Infected cell
Did you know that...?
Rabies, a fatal disease
in humans, is caused by
a virus. Louis Pasteur
and Emile Roux developed
the first rabies vaccination
in 1885.
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Activities
7. Which vital function do
viruses share with other
living things?
8. Draw and label a virus.
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4. What are infectious diseases?
An infectious disease occurs when a pathogenic microorganism
invades a living thing, and causes an illness.
respiratory
system
Microorganisms reproduce very quickly inside the body. However,
the effects of an infection are not immediate. First, there is
an incubation period. Then, various symptoms
of the illness are observed, for example, a high temperature.
When microorganisms are transmitted from a sick person
to a healthy one, contagion occurs. Transmission can take place
in many ways: see the diagram and chart.
contact
with
the skin
digestive
system
Symptoms are the effects that a disease has on the body, and
can be observed.
Vectors are insects that carry a disease from one person to another.
Mosquitos (Anopheles) can carry Plasmodium which causes malaria,
if they bite an infected person.
Some illnesses caused by microorganisms
Illness
Microorganism
Cold
virus
AIDS
virus
Pneumonia
bacteria
Transmitted
through
the air
Symptoms
sexual
contact
stuffed up nose,
sneezing, high
temperature,
coughing
general
sexual and blood
weakness,
contact
weakened defences
the air
fever, coughing,
pulmonary
infection
How microorganisms enter the body
Salmonellosis
bacteria
spoiled food
high temperature,
nausea, vomiting,
diarrhoea
contaminated
water
nausea, vomiting,
stomachache,
severe diarrhoea
Activities
Cholera
protozoan
Malaria
protozoan
Athlete’s foot
microscopic
fungus
the bite of the
headache,
female Anopheles intermittent
mosquito
vomiting, fever
physical contact
through the skin
itching and cracked
skin, scaly skin
between the toes
9. Use the diagram and chart
to classify the entry points
for each illness.
Copy the diagram and label
it with the illneses.
10. Choose two more common
illnesses. Copy the chart
headings and complete
them for both illnesses.
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Hands on
Taking and classifying samples. Observing microorganisms
Scientists obtain data from nature by collecting samples. They do this for different reasons:
• To compare. For example, on farms, blood
samples are taken from animals. These are
compared to check the animals’ health.
Compare two water samples. Then classify
the microscopic living things in the water.
• To classify. Classification helps scientists to
organise and understand the natural world.
water with leaves and soil
tap water
puddle water
1. Take the samples. Put water from a
puddle into a glass jar with a screw top.
Alternative: put water in a bowl and mix
it with some soil and dried leaves. Let it
rest for a few days. Put some tap water
into another clean jar. Label each jar.
bowl
2. Observe the samples. Using a pipette,
put three drops of puddle water onto
a microscope slide. Include a fragment
of vegetation or clay. Put three drops of
clean water onto another slide.
Look at the puddle water through the
microscope. First observe it with low
magnification, then increase it. Study all
parts of the slide for a few minutes.
Repeat the process with the tap water.
Navicula
Paramecium
Colpidium
Phyllodinea
Vorticella
3. Identify the living things. Look at
drawings of freshwater microscopic
organisms to recognise the samples
under the microscope.
Scenedesmus
Euglena
4. Classify the living things.
Can you classify them into groups?
Cosmarium
Activities
11. Did you see any microorganisms in the tap
water? Did that surprise you? Why or why not?
14. Compare vaccines and antibiotics. See page 81.
Make a Venn diagram.
12. Did you identify any living things in the puddle
water? Draw and label them. Remember to write
down the microscope magnification.
15. Can antibiotics cure a cold? See page 81. Explain
your answer.
13. Would you drink puddle water? Why or why not?
80
16. How does intestinal flora help human beings?
See page 81.
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5. How can you fight infectious diseases?
You can protect yourself from infection in several ways:
• Personal hygiene: wash your hands before eating.
• Eat and drink only fresh food and drinks.
Did you know that...?
Vaccines
A vaccine contains dead or weakened microorganisms from a specific
illness. These microorganisms cannot produce the illness, but they
can protect against it.
Penicillin was first discovered
by Alexander Fleming.
It was later developed as an
antibiotic. Penicillin has
saved millions of lives.
Vaccines teach the body how to fight an illness. Therefore vaccination
is a preventive measure. Your body can fight against microorganisms
if it is exposed to them. Most vaccines protect the body indefinitely.
Others require a booster dose, another dose, later on.
Antibiotics
Antibiotics are produced by certain bacteria and fungi. They prevent
the microorganisms that cause illnesses from growing. Antibiotics are
curative measures and must always be prescribed by a doctor. They
cannot fight illnesses caused by viruses.
6. Are all microorganisms harmful?
All viruses are pathogenic. They are parasites that
cause illnesses. A few bacteria, protozoa or
microscopic fungi are pathogenic.
• Intestinal flora are bacteria that live in human
and animal digestive systems. They are useful
because they produce vitamins.
Many microorganisms are beneficial:
• Other bacteria are used to obtain antibiotics.
Decomposer microorganisms
transform dead animals and plants
into inorganic substances. Some
are harmful.
Plankton is the primary food for many
aquatic animals.
Some bacteria are used to make food,
like cheese.
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Activities
17. Look at the drawings of a bacteria and a virus.
a. Label them. What characteristics helped you?
b. What do these organisms have in common?
a
b
h
a
b
c
a. What type of living things cause red tide?
f
e
22. Investigate. Red tide is a natural phenomenon.
It is caused by an accumulation of living things.
Red tide affects the world’s coasts, especially
in spring and summer. Each year it causes
the death of many fish, shellfish, molluscs,
mussels, oysters, cockles and other marine
bivalves.
i
g
d
b. How do you think the marine animals become
infected?
c. Can red tide affect people? Why or why not?
18. What type of organism or structure, 1-3,
corresponds to each description?
a. They are not really cells; they are obligate
parasites.
b. Autotrophs or heterotrophs with prokaryotic cells.
c. Heterotrophous, eukaryotic, unicellular organisms.
1
2
HIV virus
(0,11 mm)
Intestinal bacteria
(1 ␮m)
a. Are these bacteria autotrophs or heterotrophs?
b. Where do they obtain their nutrients?
24. Look at the protozoa in photos A-D.
3
A
B
C
D
Paramecium
(20 ␮m)
19. Microorganisms are microscopic living beings.
They are measured in micrometres: one millionth
of a metre, or one thousandth of a millimetre (␮m).
a. How big, in millimetres, is each microorganism
in the picture in activity 18?
b. Classify each microorganism: eukaryotic
or prokaryotic.
c. Which of these microorganisms is not
considered a living thing?
d. What makes prokaryotic microorganisms
different from eukaryotic microorganisms?
20. Unlike certain bacteria and pathogenic protozoa,
cyanbacteria and unicellular algae do not produce
diseases.
Why do you think this is?
21. Compare bacteria, protozoa and algae: cell type,
nutrition and habitat. Create a table.
82
23. Many bacteria live symbiotically inside the digestive
tract of herbivorous animals, like the giraffe,
elephant or cow.
What type of structures enables each to move?
25. Cavities in teeth are produced by microorganisms
like streptococcus and lactobacillus.
a. What type of microorganism are they?
b. Are cavities considered an infectious disease?
Why or why not?
c. What is the best way to prevent cavities?
26. Research beneficial microorganisms in the food
industry. Display your results in a poster.
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MICROORGANISMS
What should you know?
Monera
Kingdom
The Monera kingdom includes unicellular, microscopic,
prokaryotic organisms.
Bacteria belong to the Monera kingdom. They are
classified according to shape:
• Coccus: Spherical
• Bacillus: Rod-shaped
• Vibrio: Curved-rod shaped
• Spirillum: Helical
Protoctist
Kingdom
The Protoctist kingdom includes unicellular and
multicellular living things. They are all eukaryotes and
have no tissues. They are generally very small and include:
• Protozoa are unicellular. They are heterotrophs.
They live in both salt and fresh water. Some are
parasites. They are classified by the way they move:
flagellates, ciliates, rhizopods and sporozoa.
• Algae may be unicellular or multicellular. They are
autotrophs. They sometimes form colonies. They live
in salt and fresh water. Algae are classified as green,
brown and red.
7
Microorganisms can be harmful or beneficial.
Harmful microorganisms:
A few microorganisms cause illnesses. Contagion
occurs when microorganisms are transmitted from
a sick person to a healthy one.
VIRUSES
Microorganisms
Beneficial microorganisms:
• Decomposer microorganisms
• Plankton
• Intestinal flora
• Some are used to make food
• Some are used to obtain antibiotics and other medicines.
Viruses are extremely small.
They are not cells, so they are not true living things.
They are obligate parasites, that is, they cannot live without the host.
They consist of a capsid, an external shell and nucleic acid.
Projects
EXPERIMENT: Put moist bread in a plastic box. Observe the changes after a few days. What causes them?
WEB TASK: Find out about friendly and unfriendly microbes.
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Rock stars...
Stereoscopic microscopes illuminate solid objects from above. They are used to obtain
magnified, three-dimensional images. They are very useful for studying rocks.
Images from a
stereoscopic microscope
eyepiece
A
tube
fine focusing
knob
B
light source
coarse
focusing knob
stage
arm (limb)
C
stand
1. Match these rocks to their corresponding image above.
1
2
3
limestone
granite
2. Describe each rock sample. For example:
Granite
84
is
black/ white /grey/ reddish / cream.
heterogeneous / homogeneous.
smooth / rough / sandy.
sandstone
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and instruments
There are many different meteorological instruments used to study the Earth’s atmosphere
and weather. For example:
A thermometer
measures
temperature.
A hygrometer
measures humidity
in the air.
A rain gauge
or pluviometer
measures rainfall.
3. Look at these photos. What do you think the weather is like in each place?
A
B
The Sahara Desert
The North Pole
C
D
A rain forest
A deciduous wood
4. Match each text to its corresponding photo.
1 Temperature: high
Precipitation: very abundant
Humidity: very high.
3 Temperature: very low
Precipitation: very abundant
Humidity: very high
2 Temperature: extremely high.
5. Say what the weather is like
where you live.
Where I live the temperature is...
Precipitation: very low.
Humidity: very low.
4 Temperature: medium
Precipitation: abundant
Humidity: high
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UNIT
8
The Earth’s
atmosphere
What do you remember?
• What elements can you see
in the photo? Describe
them.
• In which part of our planet
do these phenomena form?
• What other atmospheric
phenomena do you know?
• Air is a mixture of gases.
Which are the most
abundant?
• Is the composition of air
the same at sea level as
at the top of a very high
mountain?
86
Content objectives
Key language
In this unit, you will …
Expressing amounts
• Examine the origin and composition of the
atmosphere
• Discover how living things affect the
composition of the atmosphere
• Analyse how wind, clouds and
precipitation are formed
• Study the effects of living things on
atmosphere and climate
• Make and use a meteorological instrument
The Earth’s atmosphere is about 800 km high.
The density of air is about 1kg/m3.
Comparing
The ionosphere is the highest and the thickest
layer.
The higher the altitude, the lower the density
of air.
The higher a place is, the colder and wetter it will be.
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1. What do we know about the atmosphere?
The atmosphere is made up of gases in different proportions.
Nitrogen and oxygen are the most abundant. The atmosphere was very
different 4,600 million years ago.
• The primitive atmosphere was made up of water vapour, carbon
dioxide, nitrogen, hydrogen, ammonia, methane and other oxides,
but no oxygen.
The first living beings (bacteria), produced oxygen by
photosynthesis. Molecules formed when chemical reactions took
place between some gases. These molecules fell to Earth with rain.
• The present atmosphere is made up of 78 % nitrogen, 21 %
oxygen, 1 % carbon dioxide, water vapour, and other gases, such
as argon.
Much later, the ozone layer was formed from oxygen. The ozone
layer protects life from harmful radiation from the Sun.
The layers of the atmosphere
There are four layers. The Earth’s atmosphere is about 800 km high
and is held in place by the Earth’s gravity. The separation in layers is
caused by variation in temperature with respect to altitude.
Composition of the air
Nitrogen (N2). Colourless.
Odourless. 78 % of air
Oxygen (O2).
Colourless.
Almost all living
creatures breathe it.
21 % of air.
Other gases: 1 %
Argon (Ar).
Ozone (O3)
Water vapour
Carbon dioxide (CO2)
Necessary for
photosynthesis
Activity
1. Why does oxygen in the
atmosphere make it suitable
for life? And carbon
dioxide? And water?
500 km
Ionosphere. The highest and the
thickest layer. Its temperature
increases to 1,000 °C due to X-rays
and gamma rays from the Sun.
400 km
Comets appear here.
A LT I T U D E
80 km
Mesosphere. About 40 km thick.
It contains clouds of ice and dust.
300 km
40 km
200 km
Stratosphere. About 30 km thick.
There is an increase in
temperature from −70 °C at its
lower limit to 0 °C at its higher limit.
The ozone layer is here.
Ozonosphere
10 km
100 km
80 km
Troposphere. Very thin, but
contains 80 % of the total mass of
the atmosphere. This is where
meteorological phenomena occur.
40 km
10 km
0 km
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2. What makes up the weather?
Weather describes the state of atmospheric conditions
at a certain place, over a short period of time. Weather conditions
include:
• Humidity. The concentration of water vapour in the
atmosphere.
• Clouds. Formed when rising air cools.
• Precipitation. Water that falls to the ground: rain, snow and
hail.
• Temperature. How hot or cold the air is.
• Wind. Movements of air.
Did you know that...?
Weather spreads the Sun’s
heat around the Earth. Without
weather, the tropics would get
hotter and the Poles would get
colder, until there was no life
on Earth.
Atmospheric pressure
Air has weight. The pressure it exerts on a surface is called
atmospheric pressure. It is caused by gravity, and is measured
in millibars (mb).
In the 17th century, the Italian scientist, Torricelli, proved that
atmospheric pressure decreases with altitude. Therefore, at sea
level, the pressure is higher than at the top of a mountain.
L
The density of air on the Earth’s surface is about 1 kg/m3. This
means that 1 m3 weighs 1 kg. The higher the altitude, the lower
the density of air.
Predicting the weather
996
H
0
1 00
Air moves from high pressure areas to low pressure areas.
This enables weather forecasters to predict the weather.
Air moves because the Sun heats it. Hot air rises and the colder
surrounding air moves in to take its place.
• Low pressure area. Air moves from the sea towards a land
mass. It brings humidity with it. Clouds form and
precipitations occur.
On weather maps, lines called isobars connect
points with the same atmospheric pressure.
Look at this example.
H = high pressure L = low pressure
• High pressure area. Air moves from a land mass towards the
sea. There are no clouds and the sun shines.
1008
1 016
H
1 000
12
10
992
10
04
L
988
980 984
Activities
996
2. What is atmospheric pressure?
3. Does the atmospheric pressure at
the Poles have the same value as
at the Equator? Explain.
The rotation of the Earth also makes air move in spirals.
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3. What factors affect climate?
Climate describes the characteristic pattern of weather in an area,
over a long period of time. Factors affecting climate are:
• Latitude. How far north or south a place is from the Equator.
At the Equator, solar energy is concentrated and causes high
temperatures. Towards the north and south, solar energy is
more spread out and causes cold temperatures.
• Altitude. The height above sea level. The higher a place is,
the colder it will be.
• Distance from the sea.
– Sea water heats up slowly and cools down slowly. In winter
the sea releases heat, keeping coastal areas warmer.
– Land heats up quickly and cools down quickly. In summer,
cold sea keeps coastal areas cooler.
• Ocean currents.
– Warm ocean currents flow up from the tropics to the poles
and warm up surrounding areas, especially in winter.
– Cold ocean currents can lower temperatures in an area.
Activities
4. Look at the four factors that
affect climate. Can you define
how these affect the climate in
your part of the country?
5. What will the weather probably
be like if you are looking at
cirrus clouds? And if you are
looking at cumulonimbus
clouds?
Clouds and precipitation
• Rain occurs when condensation makes large, heavy droplets
which fall to Earth. Snow and hail occur when the water
vapour in the air freezes.
• Clouds form when rising air cools. Some of the water vapour
molecules in the air condense to form cloud droplets or ice
crystals.
There are three basic types of clouds: cirrus, cumulus and
stratus. There are many variations of these.
Cirrus. High, thin clouds. These
form above 6,000 m. They
normally mean fair weather.
Cumulus. Like cotton wool. They form
at about 1000 m. They can develop into
cumulonimbus: thunder clouds.
Coastal areas have milder weather than
inland areas.
Stratus clouds. Low, horizontal clouds.
These normally cover most of the sky.
Usually no precipitation falls.
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4. What is meteorology?
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1 008
H
1 024
1 00 0
1 016
Meteorology is the study of different atmospheric variables to make weather
predictions. Meteorologists collect information about temperature,
precipitation, wind, the humidity of the air, atmospheric pressure and clouds.
1 016
1 008
1 016
1 02 4
Meteostat photo
L
Meteorological map
Map with weather symbols
The most important meteorological instruments
A thermometer
measures
temperature.
A barometer measures
atmospheric pressure.
Activities
A rain gauge /
pluviometer
measures the
amount of rainfall
per square metre.
A hygrometer measures
the humidity in the air.
6. You hear this report on the
radio:
Wind speeds were 95
kilometers an hour and 200
litres of rain fell per square
metre. What instruments
were used to collect this
information?
7. Copy and complete.
Metereological
instrument
anemometer
An anemometer
measures wind
speed.
90
A weather vane shows
the direction the wind is
coming from.
barometer
Measures/
Shows
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Hands on
Observing the weather
Make and use an anemometer to measure wind speed
An anemometer measures wind speed. Remember that wind is simply moving air.
Materials
– A pencil with an eraser end
– A drawing pin
– A plastic plate
– One coloured plastic cup
– Three white plastic cups
– A stapler
1. a. Staple each cup to the plate so that
they are spread out equally.
b. Pin the plate to the eraser on the end
of the pencil. Make sure the plate
can spin round easily.
c. Take your anemometer outside.
2. Watch the wind blow the cups around.
Count the number of times the coloured
cup passes in one minute.
(Revolutions per minute = RPM)
3. Record the wind speed for one week.
At the same time, observe the weather
for each day. Record if it is fair or unstable.
4. Interpret the results
Can you prove or disprove the following
hypothesis using your results?
High wind speed is directly related to unstable
weather.
How to calculate the wind speed
First, calculate the circumference (in metres)
of the circle made by the rotating paper cups.
Multiply the RPM value by the circumference
of the circle. This gives you the approximate wind
speed in metres per minute.
Activities
8. How cloudy is it when the air pressure is lowest / highest?
9. What kind of wind is associated with rain?
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5. How do humans impact on the atmosphere?
Human activities cause atmospheric pollution: the
release of harmful substances called pollutants into
the atmosphere.
think that air pollution is causing the Earth’s
surface to heat up.
Most pollutants are gases: sulphur dioxide, carbon
dioxide and nitrogen oxide. They are produced by
combustion from motor vehicles, aeroplanes, by
burning fossil fuels, and from industrial activities.
Acid rain
Air pollutants can also be particles of liquid and
solid molecules: ash from forest fires, black smoke,
dust and soot.
Pollulants in the air can cause: respiratory system
irritation, eye irritation, increase in asthmatic
processes, headaches.
Global warming
In the last century, our atmosphere has warmed
between 0.5 and 0.9 °C on average. Some scientists
Rain is naturally slightly acidic due to carbon
dioxide dissolved in it. Pollutants such as sulphur
dioxide and nitrogen oxide, form acids when
mixed with the rain.
The hole in the ozone layer
Ozone exists throughout the atmosphere, mainly
concentrated in the stratosphere. Ozone is being
destroyed by air pollution. Chemicals called
chlorofluorocarbons (CFCs) used in aerosols and
refrigerators escape into the atmosphere. They
react with ozone and destroy it. Harmful solar
radiation may enter through this hole.
Human activities that pollute the atmosphere
Human activity
Pollutant
Consequences
gases used in
aerosols, air
conditioners
CFC gases
Reduces the amount of gas
in the ozone layer so more
ultraviolet radiation reaches the
Earth. Skin cancer results.
particles released
from burning coal
and other fuels
soot
Cities are dirtier. Buildings are
damaged. Can cause lung
diseases.
burning fossil fuels:
coal, petrol
carbon
dioxide
(CO2)
Global warming: tropical cyclones,
polar ice melts, sea levels rise,
severe droughts
burning gasoline
sulphur
and nitrate
dioxides
Acid rain: damages buildings,
vegetation and harms herbivorous
animals.
The hole in the ozone layer allows in harmful
UV rays. These cause sunburn.
Air contamination
from industry
Acid rain damages this statue.
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6. What is the greenhouse effect?
The greenhouse effect is a natural
phenomenon. It is essential for keeping the
temperatures on Earth suitable for life.
sunlight enters
the ground
and air get
hotter
The atmosphere absorbs a great amount of
solar radiation. CO2 in the atmosphere acts
like the glass walls of a greenhouse. It traps the
heat and prevents it from returning into space.
In this way the Earth does not lose too much
heat. If there were no atmosphere, our planet
would be much colder.
The increase of carbon dioxide
The amount of carbon dioxide in the
atmosphere has gradually increased over the
last 200 years. Carbon dioxide is produced
when fossil fuels are burned; by living things
breathing; by fires, and by erupting volcanoes.
Greenhouse
made of glass
The Sun
heats the air
Some CO2 is dissolved in the oceans and
absorbed by growing plants. Unfortunately,
people are destroying plants and burning more
and more fossil fuels. This means more carbon
dioxide is produced. An increase in carbon
dioxide means more heat is trapped. Therefore
the average temperature of the Earth is
increasing.
atmosphere
traps the heat
Protecting the atmosphere
When pollution is reduced, global warming,
the hole in the ozone layer and acid rain are
also reduced. By saving energy, the atmosphere
will improve and our health will be much
better. You are part of the solution.
• use hot water carefully: do not waste it
• turn off unnecessary heating and electrical
devices
• travel by public transport, by bike or
on foot
• avoid aerosols with CFCs
• recycle paper, plastic and glass
• plant trees
The greenhouse effect
Activities
10. Talk about pollutants.
Where
does (carbon dioxide)
do (CFC gases)
What damage
does it
do they
come
from?
cause?
11. Survey. Ask your classmates: Do you protect
the atmosphere? Do you recycle paper? Etc.
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Activities
12. Study the map and answer the questions.
a. Is cloud and precipitation more likely in Spain
or in the UK?
18. Indicate the meteorological role of each instrument
and what it measures.
b. What will the weather be like in Spain?
c. Where is the low atmospheric pressure
coming from? Central Europe or the Iberian
Peninsula?
d. Copy the map. Use arrows to show the wind
direction.
L
19. Explain the differences between the primitive
atmosphere and the Earth’s atmosphere today.
20. Look at the table. It shows the atmospheric
pressure at different times.
12:00
Time
H
14:00
16:00
18:00
Atmospheric
1 020 mb 1 016 mb 1 010 mb 1 007 mb
pressure
13. Why do mountain climbers carry oxygen tanks
to climb Mt. Everest?
14. What are the five principal components of air?
For each one indicate:
a. Is the atmospheric pressure increasing
or decreasing?
b. Is there a possibility of high pressure or low
pressure?
c. Will there be a high or low chance of clouds?
a. its proportion
21. Label the maps: weather map or isobar contour
map.
b. its origin
c. if it has a role in an important process.
Do the two maps show the same weather? Explain.
15. Investigate. Ozone is very scarce, but very
important. Explain why it is important. Tell how it
can be beneficial and harmful.
16. Draw a greenhouse. Explain what the greenhouse
effect is and how it works.
L
17. Copy and complete with information about
the layers in the Earth’s atmosphere.
Approximate
thickness
Troposphere
Stratosphere
Mesosphere
Ionosphere
94
Description
of the layer
22. Give three reasons why the atmosphere is essential
for life. Use these ideas:
a. Sun’s radiation
b. gases and living things
c. control of Earth’s temperature
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What should you know?
Climate
The average weather over a long period of time.
Human
impact
Human activity creates substances that pollute the
atmosphere: An increase in carbon dioxide produces
the greenhouse effect, which causes climate change.
• CFC gases eliminate the ozone from the stratosphere.
• Sulphuric oxide and nitrogen oxide cause acid rain.
• Soot pollutes the air and creates health problems.
1 024
Studied by meteorologists who measure temperature,
precipitation, atmospheric pressure, winds, and humidity.
Weather forecasts are based on this information
and show it in:
• Pressure / isobar contour maps and weather symbol
maps
Air moves from high pressure areas to low pressure areas.
When air cools, the humidity can condensate or freeze,
forming clouds and precipitation.
H
1 024
1 016
1 008
1 02 4
1 016
Changes
in the
atmosphere
The primitive atmosphere contained no oxygen. It underwent several changes:
• Water formed the hydrosphere. Carbon dioxide was instrumental in photosynthesis.
Photosynthesis increased the amount of oxygen.
1 008
THE ATMOSPHERE
Origin
The atmosphere is composed of air. Air is a mix of gases:
• 78 % nitrogen, 21 % oxygen, 1 % other gases
• Variable quantities of water vapour
The atmosphere is divided into layers:
• Ionosphere: The outermost layer. It extends to 500 km above the Earth.
• Mesosphere: 40 to 80 km above the Earth.
• Stratosphere: Between 10 and 40 km above the Earth. It contains the ozonosphere.
• Troposphere: From the Earth’s surface to 10 km above the Earth. Meteorological
phenomena occur here.
1 016
Composition
and
structure
8
L
Projects
PROJECT: Weather maps. Collect the weather maps from a newspaper during one whole week. Stick them
onto a chart. Write the weather each day next to each map.
WEBTASK: You are planning a trip to London. What is the weather like today?
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UNIT
9
The hydrosphere
What do you remember?
Look at the picture and
answer the questions.
• Where can water be found
on our planet?
• How is sea water different
to water in rivers and
lakes?
• What is the water cycle?
Can you describe it?
• Why is it important not
to waste water?
• Do you know some easy
ways to save water?
Content objectives
Key language
In this unit you will ...
Expressing amounts
• Find out how water is distributed on Earth
68.7 % occurs in the form of ice and snow.
• Learn about the properties of water
Describing
• Learn about ocean movement: waves,
currents and tides
Water is attracted to other water.
Water is a powerful solvent.
• Describe the water cycle
Expressing direction
• Identify uses of water and causes of water pollution
Water filters into the ground.
Currents move through the sea.
Waves transport sand along the coast.
• Study the effects of temperature on condensation
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1. Where is there water on Earth?
There is salt water and fresh water on Earth.
Distribution of water on Earth
WATER
97% of the water on Earth is salt water.
It is found in the oceans.
3% of the water on Earth is fresh water.
Total water on Earth
Salt water 97 %
Fresh water is found in:
68.7% is ice and snow from glaciers
or at the North and South Poles.
30.1% is groundwater: water
below the Earth’s surface.
0.9% is in the atmosphere, in living
things, etc.
0.3% is surface fresh water.
SURFACE
FRESH WATER
FRESH WATER
Fresh water 3 %
These small squares represent all the water
in the hydrosphere.
Fresh water distribution
0.9% other
0.3%
fresh water
68.7% ice
and snow
30.1%
ground water
Surface fresh water is found in:
87% is found in lakes.
11% is found in swamps.
2% is found in rivers: it is fit
for human consumption.
Surface fresh water distribution
rivers 2%
swamps 11%
lakes 87%
Activities
1. How much water is there for human
consumption on Earth? Explain.
2. Represent the pie chart information in two bar
graphs.
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2. What are the properties of water?
Water is a substance with unique properties. It plays an
important part in the processes that occur on the
Earth’s surface and is essential to living beings.
Water is made up of molecules. Each molecule of water
is made up of one atom of oxygen and two atoms of
hydrogen. At room temperature the molecules can
move about freely: water flows.
The main properties of water are:
Did you know that...?
Water covers 75% of the surface of
our planet.
This characteristic is unique in the
solar system.There is water on other
planets, but it is never found in a liquid
state nor in such huge quantities.
• A powerful solvent. It dissolves many components
of rock. When water evaporates, it leaves deposits of
mineral salts.
• Absorbs heat. Water moderates the Earth’s climate
by absorbing heat in summer and emitting heat in
winter.
• Cohesion and adhesion. Water is attracted
to water: this is called cohesion. Water sticks to
itself, it can travel throughs vessels in plants to
transport food to the leaves. Water transports
substances throughout the bodies of living things.
Water molecules are also attracted to other materials:
this is called adhesion. As a result, water wets
surfaces such as soil and rocks.
PACIFIC OCEAN
Anomalous dilation. When water freezes, it dilates or increases in volume. As a result, the volume of ice is greater than the
same mass of water in liquid form.
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3. What are the properties of sea water?
Sea water has special properties:
• It is salty. Each litre contains about 35 grams of dissolved
salts.
• It contains dissolved gases: mainly nitrogen, oxygen and
carbon dioxide. These gases are dissolved in the water by
two processes:
Salts dissolved in sea water
chlorides 87%
– the movement of the waves which mixes water with air.
– the activity of aquatic beings. Oxygen is produced by
the photosynthesis of aquatic plants; living things breathe
out carbon dioxide.
• The temperature of salt water varies with depth. At the
sea surface, the temperature is higher. In the deepest
zones, the temperature of the water is lower: between 4ºC
and ⫺2ºC.
others 2%
sulphates 11%
Movements produced in the oceans
Ocean waters move in three ways: waves, currents and
tides.
• Waves occur on the surface. They are caused by the wind.
Waves mix water with the air above the surface, dissolving
a lot of oxygen in this zone. Movement of gases occurs
from the atmosphere into the oceans, and from the oceans
into the atmosphere.
Wave action causes cliff erosion and creates beaches.
Waves transport sand and mud along the coast and out
to sea.
• Ocean currents are masses of water which move like
rivers through the sea. The currents are produced by
wind, differences in temperature, and differences in
salinity.
• Tides are the periodic rise and fall of the sea level. They
are caused by the gravitational attraction of the Moon
and, to a lesser extent, the Sun.
Wave action causes rock erosion.
Activities
3. Look up the following terms: solvent, evaporation, cohesion, anomalous dilation and adhesion.
4. Think about cohesion and adhesion. Why are these properties so important for living things?
5. Is there more oxygen dissolved in sea water near the surface or in the deep, darker zones? Explain.
6. Why do you think sea water in warm areas contains more salt than sea water in cold areas?
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4. Where is fresh water found?
Fresh water is found on the continents. It contains much less salt than sea water. It is found
in different forms: lakes, rivers, torrents, underground rivers, pools and glaciers.
groundwater
snow from the
mountain tops
stream
river
wetlands
lake
lagoon
Streams or torrents are water courses fed by rain. The flow of water
varies a lot from season to season.
Wetlands are areas of marshlands and swamps where the ground is
inundated all year round.
Glaciers are formed from the accumulation of snow on mountain tops.
Rivers are permanent water courses. The River Nile is the longest
river in the world.
Groundwater is water located beneath the ground surface.
Lakes are bodies of water of different sizes surrounded by land.
Example: Lake Victoria, Africa.
River valley
100
Groundwater in a cave
Activities
7. Copy the diagram and label
the bodies of fresh water.
Which bodies of fresh
water can you find where
you live?
8. Look out your window. Draw
and label the water cycle
processes you observe.
Lake
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5. What is the water cycle?
The water cycle is the movement of water on, above and below
the surface of the Earth. It consists of the following processes:
evaporation, evapotranspiration, condensation, precipitation,
surface runoff and infiltration.
• Evaporation. Liquid water changes to a gas (water vapour).
Water passes from the hydrosphere to the atmosphere.
• Evapotranspiration. Water evaporates into the atmosphere
from the leaves and stems of plants.
• Condensation. Water vapour changes to liquid, forming
clouds and dew.
• Precipitation. Water in the clouds falls to the ground as rain,
snow or hail.
• Surface runoff. Surface water moves across the land and
forms rivers and streams.
• Infiltration. Surface water filters into the ground. This
occurs more easily if the ground is porous.
condensation in
the form of clouds
water vapour
precipitation
clouds
ent of
m
e
v
mo
precipitation
evaporation
surface runoff
evaporation
surface rocks
evaporation
evapotranspiration
infiltration
groundwater
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6. What is water used for?
Water is the most abundant substance in living things. Every
day your body loses 1.5 to 2 litres of water through sweat,
urine and respiration. You replace it by drinking water. Water
is used in different ways, depending on the country.
The main uses are:
• Agriculture. To water crops.
• Industry. Water is used in many industrial processes.
• Domestic use. Drinking water is used for human
consumption, cleaning, etc.
Watering crops
How can you save water?
Water is a scarce resource. You can reduce domestic water
consumption if you ...:
• Take a shower, not a bath.
• Turn off taps when brushing teeth or soaping your body.
• Load dishwashers and washing machines completely before use.
• Install water-saving devices in the lavatory cistern.
7. What pollutes water?
Water becomes polluted for many reasons. For example, as a
result of:
Oil refineries consume a lot of water
• Waste water from industries and farmland.
• Sewage water from towns and cities.
• Oil slicks caused by the accidental spillage of crude oil at sea.
• Agricultural fertilizers and pesticides which filter into
the soil and pollute rivers and groundwater.
Some causes and prevention of water pollution
Causes
Prevention
Rubbish thrown in the
countryside, on beaches,
in rivers, etc.
Pick up rubbish and place in rubbish bins.
Toxic waste from domestic
use makes it difficult and
expensive to purify water.
Do not throw paints, oils or solvents down
the drain or toilet.
Chemical pollution
Recycle batteries. They release toxic
chemicals into the soil, then into rivers.
102
Cleaning water polluted by an oil slick
Activity
9. Use information from this page to
make a water poster. Example: Take
showers. Don’t throw rubbish on the
beach. It pollutes the water.
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Hands on
Studying the effects of temperature on condensation
60 °C
18 °C
6 °C
0 °C
Controlling variables
in an experiment
To see how temperature affects the
condensation of water vapour, compare
masses of air at different temperatures.
Keep all other variables equal.
B
A
C
D
Keeping all the variables equal, and
modifying only one is called controlling
variables.
Procedure
1. Place four identical glasses on a table. Label them 4. Observe the table. What can you conclude from
A, B, C and D. Place a thermometer in each one.
2. Put very hot water in glass A; water at room
temperature in glass B; three ice cubes in glass
C. Fill glass D with ice cubes. Make sure the four
glasses are completely dry on the outside.
3. Wait twenty minutes. Then observe and note
down the amount of condensation on the
outside of each glass.
Water
condensation
outside the
glass.
the effects of temperature on the process of
condensation?
Glass
Temperature
Appearance
A
60 ºC
No condensation
B
18 ºC
No condensation
C
6 ºC
Small drops
D
0 ºC
Large drops which slide
down the glass
Controlling variables. The four glasses are
surrounded by the same air, so we can assume
that atmospheric pressure, particles in the
atmosphere, humidity, etc., are the same for
each glass. These are the controlled variables.
Only the temperature varies. The temperature
is the independent variable, that we changed for
the purpose of the experiment. The amount of
condensation of the humidity in the air
depends on the temperature, so the
condensation is the dependent variable.
Activity
10. Breathe on each glass to make the surrounding air more humid. Does the amount of condensation
increase in each case? Which controlled variable have you now modified?
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Activities
11. This diagram shows the distribution of fresh water
in the hydrosphere. Label the corresponding
sections.
A
C
17. Look at the diagram of the water cycle.
B
12. Water transports dissolved salts to the sea.
Water also transports nutrients in our blood.
What property enables water to do these things?
13. If you water the ground on a hot day, you notice the
atmosphere becomes cooler.
a. Copy the diagram and label each process:
evaporation, condensation, evapotranspiration,
precipitation, surface runoff and infiltration.
b. What role do plants play in the water cycle?
18. What are the main sources of water pollution
caused by human activity? Example:
What causes this effect? How is it similar to feeling
cold when you get out of a swimming pool or the
ocean?
14. There is less difference between winter and
summer temperatures on the coast, than in the
interior of the country.
What is the cause of this difference, and what
property of water would explain it?
15. If you put a bottle of water in the lavatory cistern,
this reduces water consumption. Why is this?
16. About 15 litres of water a minute flow through an
open tap.
19. Fill a small bottle of water to the top. Close it tightly
and put it in the freezer. Depending on the type of
plastic, it may break or change shape.
a. Why does this happen?
b. Would this happen to a glass bottle?
20. Complete the chart.
Water on Earth
Percentage
of the total
Salt water
rivers, lakes,
Continental
water
groundwater
ice and snow
surface fresh
a. A person cleans his teeth three times a day and
takes a shower once a day. Calculate how much
water he saves if he turns off the tap for two
minutes while he cleans his teeth.
b. And if he takes five minutes less in the shower?
104
21. When water passes from the biosphere to the
atmosphere, what is this process called?
22. Explain what role the Sun plays in the water cycle.
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THE HYDROSPHERE
What should you know?
Water
distribution
97 %: salt water. 3 %: fresh water, of which:
• 68.7 %: is ice and snow from glaciers or at the Poles.
• 30.1 %: is groundwater.
• 0.3%: is surface fresh water.
• The remaining 0.9%: is in the atmosphere and living creatures.
Properties
of water
•
•
•
•
•
Movements
of ocean
waters
The water
cycle
Uses of water
9
Good solvent. Transports substances inside living things.
Absorbs large quantities of heat. Moderates temperature differences in climate.
Anomalous dilation. Water dilates when it freezes.
Cohesion: water molecules are attracted to other water molecules.
Adhesion: water molecules can be attracted to other materials.
• Waves. Caused by the wind. Waves mix water, causing
air-gas exchange. They cause erosion of cliffs, and
transport materials.
• Currents. Movement of large bodies of water by
prevailing winds. Cause differences in water salinity and
temperature.
• Tides. Rise and fall of sea water levels due to
gravitational attraction of the Moon and the Sun.
Water from the hydrosphere moves through the suface of
the Earth and the atmosphere.
The processes are: evaporation, evapotranspiration,
condensation, precipitation, runoff and infiltration.
• For agriculture. To water crops.
• For industry. Used in many industrial processes.
• Drinking water has domestic uses. For human consumption, cleaning, etc.
Water is contaminated by:
• Waste water from industries and farmland.
• Sewage waters from towns and cities.
• Oil slicks at sea.
• Fertilizers and pesticides filter into the soil and pollute rivers and groundwater.
Projects
POSTER: Draw a frozen lake. Show the living things that exist under the ice. Add labels and text:
These animals live...
WEB TASK: Calculate the amount of water you use in one week for showers or baths.
Compare your consumption with your classmates’.
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UNIT
10 Minerals
What do you remember?
Look at the gold mine and gold sample in the photograph.
• Where is gold is found?
• Is gold a solid, liquid or gas?
• Is it natural or man-made?
• Do you think there is a lot of gold available on Earth?
Content objectives
Key language
In this unit, you will …
Comparing
• Learn the definition of a mineral
Diamonds are harder than talc.
• Identify the properties of minerals
Describing
• Classify minerals
Some minerals have a metallic colour.
Mica can be scratched with a fingernail.
• Learn to use the Mohs Scale of Hardness
Classifying
• Use a mineral key to identify minerals
Non-silicates are classified into five groups.
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1. What are minerals?
Did you know that...?
Minerals are naturally occurring, inorganic, solid substances.
They have a definite chemical composition and specific physical
properties.
All minerals must be:
naturally ocurring ⫽
solid substances ⫽ not a liquid or a gas
not made by humans
The Earth’s crust is made
up of rocks, and rocks are
made up of minerals. Oxygen
is the most abundant element
in the Earth’s crust. More than
half the weight of a rock is
made up of oxygen!
definite chemical composition ⫽
inorganic ⫽
not from living things
calcite
the atoms composing the solid have
an orderly, repeated pattern
All minerals are solid substances. Water and mercury have most
of the characteristics of minerals, except they are liquid at room
temperature. They are called mineraloids, not minerals.
Pyrite. Like all
minerals it
is a naturally
occurring,
inorganic, solid
substance.
Pyrite has
a definite
chemical
composition:
iron sulfide.
Mercury. It is a naturally occurring,
inorganic, liquid substance.
Mercury is
a mineraloid.
amber
Activities
1. Look at the photos. Answer these questions
for each one:
a. Is it a solid?
b. Does it occur naturally, or does someone make it?
c. Is it made from living things?
d. Is it organic or inorganic?
2. Are they minerals or not? Answer using the table.
…
is
is not
a mineral because
it is
it is not
gold
diamond
natural.
inorganic.
solid.
Example: An animal bone is not a mineral because
it is not inorganic.
water
animal
bone
plastic
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2. What are minerals composed of?
Minerals are composed of one or more chemical elements.
The chemical elements of each mineral are arranged in a
particular way.
A chemical element is a substance which is made up of only
one kind of atom. An atom is the smallest particle of matter.
Oxygen, hydrogen, iron and gold are examples of chemical
elements.
smoky quartz
agate
milky quartz
The chemical composition and the main physical properties are the same
for all quartz. Smoky quartz, agate and milky quartz are varieties of quartz.
The colours are different because of impurities in the samples.
Does the chemical composition of a mineral change?
Quartz is a mineral. The chemical composition of quartz is always
the same, because it is always composed of the same elements.
The chemical composition of a mineral determines its physical
properties. Quartz from Spain has the same properties as quartz
from America.
Impurities in minerals
Minerals can be found with impurities. Impurities are small
amounts of other substances which are not part of the mineral.
These impurities can change some of the properties of the mineral.
For example, quartz is usually colourless, but it can be found
in several different colours.
108
Activities
3. Study the photos of quartz.
What colours can you see?
Why can quartz be several
colours?
4. Research other varieties of
quartz. What colours are they?
a.
b.
c.
d.
e)
f)
Amethyst
Jasper
Citrine
Creolite
Rose quartz
Rock crystal
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3. How are minerals extracted and used?
Mineral extraction and its consequences
A
B
C
D
Minerals are found everywhere in the Earth’s crust. They are
extracted in different ways. Some minerals are found dispersed
in rocks. For example, 1kg of granite rock contains 340g
of quartz.
Other minerals occur in mineral beds in high concentration.
They are extracted in:
• surface mines when they are in layers which are relatively
close to the surface.
• underground mines when they are deep in the Earth’s crust.
Extracting minerals can damage the environment in several ways.
1. Washing the soil to isolate
minerals pollutes rivers and
streams.
2. Surface mines destroy vegetation.
3. Lorries, and other heavy vehicles
make a lot of noise. Traffic pollutes
the air, soil and water.
4. Soil and rocks from excavation
is left in huge tips.
Minerals are used in everyday life
• At home: Fluorite is used in the composition
of toothpaste. You might use talc after
your shower. The salt you put on your food
is the mineral halite.
• At school: Your pencil is made of graphite.
Your digital watch can be made using quartz,
aluminium, gold or silver.
• In the shops: Gold, silver and platinum are
used to make jewellery. Precious stones are
minerals: diamonds, sapphires and amethysts.
Your dentist sometimes uses gold to fill teeth.
• Construction materials: Plaster is made from talc.
Cement is made from calcite. Glass is made
from quartz.
Activities
5. Match each photo, A – D above,
with its environmental impact, 1 – 4.
6. What minerals are used to make
these things?
–wedding rings – cement – glass
– table salt
7. Research.
a. Find out about other things
which are made of minerals.
b. What metals are obtained
from minerals?
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4. How are minerals classified?
There are many different minerals, found mainly in stones and rocks.
Minerals are formed by the combination of chemical elements found
in the Earth’s crust.
Oxygen is the most abundant element of the Earth’s crust,
about 47 %. Silicon is the second most common, about 28 %.
Silicates
Oxygen and silicon combined together produce silicates. Silicates are
the most abundant minerals on Earth.
The most abundant
elements in the Earth’s crust
Element
Percentage
Oxygen (O)
47 %
Silicon (Si)
28 %
Aluminium (Al)
7.9 %
Iron (Fe)
5.0 %
Calcium (Ca)
3.6 %
Rest
8.5 %
These common silicates make up many rocks:
• Quartz. Usually found in granite rocks or sandy river sediments.
Very hard. Used in jewellery.
• Feldspar. Found in many rocks such as granite and basalt.
Used in glass and ceramics industries.
• Mica. Abundant in granite. There are two types: white mica,
called muscovite and black mica, biotite. Used in electronic
insulators and paints.
• Olivine. Very common. Olive green in colour. Found in volcanic
rocks. Used to make jewellery. Also used as an abrasive.
Activities
8. Use the information from
the table of the most
abundant elements to make
a bar graph.
9. Summarise the information
on silicates in a chart.
Mineral
Found in
Colour
Uses
Olivine.
Olive green
Muscovite. White, yellow, grey. Glassy
Feldspar. White or pink.
Glassy
Biotite. Black. Glassy
110
Quartz. Several colours. Glassy
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Non-silicates
Non-silicates are all the minerals that are not silicates.
They are minerals that do not contain silicon.
Common non-silicates are classified into groups as:
• Native elements. These are minerals made up of a single
element. For example, gold, silver, copper, and sulphur.
• Oxides. This group of non-silicates are made up of oxygen
and one other element. For example, oligiste
is a source of iron ore from which
iron is extracted.
Did you know that...?
Diamonds and graphite are both
made up of pure carbon. They
have the same composition, but
their internal organisation is
different. Their properties are
different, too. Diamond is the
hardest mineral. Graphite is
soft: it is used to make pencils.
• Sulphides. These are minerals
made up of sulphur and a metal.
Galena is the source of lead ore.
• Carbonates. Minerals made up
of carbon, oxygen and a metal.
For example, calcite.
• Halides. Minerals made up
of a metal and chloride or fluoride.
For example, halite.
Halite. White or transparent
Calcite. All colours. Glassy.
Stalactites form when calcite dissolves
in water. The water evaporates
and the calcite remains.
Activities
10. What is the difference between silicates and non-silicates?
11. List the minerals on these pages as silicate or non-silicate.
12. Match each term with its composition:
a. oxide
1. metal ⫹ chloride / fluoride
b. sulphide
2. oxygen ⫹ another element
c. carbonate
3. sulphur ⫹ metal
d. halide
4. carbon ⫹ oxygen ⫹ metal
13. Diamonds are 100 % carbon. Which group of minerals
do they belong to?
Native gold
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5. What are the properties of minerals?
• Colour. Some minerals are always the same
colour. For example, sulphur is always yellow.
Quartz can be different colours.
• Streak. The streak of a mineral is the colour
of the powder left on a streak plate (a piece of
unglazed porcelain) when the mineral is scraped
across it.
• Shape. Minerals can be geometric or irregular.
• Cleavage is how a mineral breaks up or cleaves.
For example, mica cleaves in sheets, but galena
cleaves in cubes.
• Lustre refers to the way minerals reflect light.
Minerals can be classified as:
– metallic: like metal:
for example, pyrite
– non metallic:
waxy like oil or
fat dull not shiny
glassy like glass
• Hardness measures how a mineral reacts to
being scratched.
Mica cleaves
in sheets.
Activities
14. Study the Mohs Scale of
Hardness and describe each
mineral.
Talc is
harder than
apatite.
softer than
15. Describe your test for hardness.
Oligiste leaves a red streak.
a finger nail?
Can
a nail?
you
talc with
a piece of glass?
scratch
a diamond?
What is the Mohs Scale of Hardness?
In 1812, Frederick Moh devised the Mohs Scale of Hardness.
He selected ten minerals and arranged them in order from
1 to 10. The mineral with the highest number is the hardest.
The mineral with the lowest number is the softest. The Mohs
Scale is used to compare the hardness of any mineral.
Minerals not on the scale are given an intermediate number.
For example, galena has a hardness of 2.5.
16. Look for information on minerals
on the Internet. Classify more
minerals by colour, lustre and
hardness.
MOHS SCALE OF HARDNESS
G
HARD: can be scratched with glass
SOFT: can be scratched with a nail
VERY SOFT: can be scratched
F
with a fingernail
G
G
1
Talc
112
2
Gypsum
3
Calcite
F
4
Fluorite
5
Apatite
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Hands on
Using a mineral identification key. Classifying minerals
1. Identify a mineral with this key:
b. Study the colour: is it light or dark?
a. Study the lustre: is it metalic or non-metallic?
metallic
non-metallic
light
dark
c. Test the hardness. Use the Mohs Scale of Hardness and these tools.
Each mineral can scratch only those minerals below it on the Mohs Scale.
The harder the mineral, the harder the tool needed to scratch it.
fingernail
copper coin
steel nail
glass
2. Study the minerals in this unit, then copy and complete the chart.
Mineral
Colour
Lustre
Hardness
Mica
Olivine
dark green
Can be scratched with a nail
Calcite
Pyrite
Talc
Quartz
FG
6
Orthoclase
F
VERY HARD: can scratch glass
7
Quartz
8
Topaz
9
Corundum
10
Diamond
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Activities
A
17. Look at photos A and B.
a. Which one represents a mineral?
b. Which one represents a mixture of different
substances?
A
26. Are these minerals?
Explain why or why not.
a. a rhinoceros horn
b. a tortoise shell
c. a snail shell
B
B
C
18. Can you name minerals that do not contain oxygen?
19. Which of the following are characteristics
of minerals?
a.
b.
c.
d.
e.
f.
g.
They are inorganic.
They are a combination of two substances.
They have a definite chemical composition.
They are artificial.
They are natural.
They are made of organic material.
They are solids.
27. Copy and complete the table about the use of
minerals. Give several examples for each place.
MINERALS IN EVERYDAY LIFE
Mineral
halite
At home
Use
table salt
talc
fluorite
At school
In the shops
20. What do you call minerals with no silicon
in their composition? How many main groups
are there?
21. What number on the Mohs Scale of Hardness
would these minerals have?
a. A mineral that can be scratched by talc.
b. A mineral that can scratch talc, and can be
scratched by gypsum.
22. Study the minerals on pages 112 and 113 and test
your partner:
What mineral is this? Can you describe the colour?
How hard is it? Is the lustre metallic or non-metallic?
Jewellery
Construction
28. Many Ancient Egyptian
statues are still standing
today. The statue
in the photo is made
of alabaster.
Describe alabaster:
is it hard or soft?
Explain your answer.
Hint: alabaster is 2-3
on the Mohs Scale.
23. What minerals can you identify at home or at school?
24. Research. Where are diamonds obtained?
What different colours of diamonds are there?
Make a file card about diamonds.
25. Choose a mineral. Research its most important
uses in daily life. Make a poster to illustrate
these uses.
114
29. Many people have mistaken pyrite for gold.
This is why it is often called ‘Fools Gold’.
Pyrite is quite easy to distinguish from gold.
If you had a sample of each mineral, how would you
distinguish them?
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What should you know?
10
MINERALS
Minerals are naturally ocurring, inorganic, solid substances
with a specific chemical composition and specific physical properties. They
are made up of elements. The most abundant elements in the Earth’s crust
are oxygen (47 %) and silicon (28 %).
Mineral
classification
There are two main groups of minerals.
• Silicates are composed of silicon and oxygen.
The most common silicates are quartz, feldspar, mica
and olivine.
• Non-silicates are classified by their chemical
composition as: native elements, oxides, sulphides,
carbonates and halides.
Properties
• Colour. Some minerals are always the same colour.
Others, like quartz, can be different colours because
they contain impurities.
• Lustre refers to the way a mineral reflects light:
metallic; non metallic.
• Hardness measures how a mineral reacts
to being scratched. Minerals are classified on a scale
of 1 to 10. 1 is soft. 10 is the hardest.
• Streak is the colour of the powder left when
a mineral scratches a surface.
• Cleavage is how a mineral breaks up: in sheets or cubes.
Extraction
and uses
Minerals occur in high concentration in mineral
deposits. They are extracted in surface mines
or underground mines.
Uses:
• Sources of metal: lead, iron, etc.
• Jewellery: gold, silver, diamonds and quartz
• Construction materials: plaster, cement
• Home: table salt, toothpaste, watches …
Projects
EXPERIMENT AND REPORT: You cannot scratch quartz with a nail. Can quartz scratch the nail?
PROJECT: Mineral Exhibit. Use the information from the table on page 113. Prepare a file card for each mineral.
WEB TASK: What is your birthstone? What are some of its properties?
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UNIT
11 Rocks
What do you remember?
• What are rocks made up of?
• Are all rocks solid, or can a rock exist in liquid state at normal temperature?
• Can you name some things that granite and marble are used for?
Content objectives
Key language
In this unit, you will…
Expressing a purpose
• Explore some uses of rocks
Granite and marble are used for sculptures.
• Understand the relationship between
minerals and rocks
• Recognise common types of rock
• Analyse how rocks are formed
• Classify rocks by their properties
• Discover the processes involved
in the rock cycle
116
Making impersonal statements
Igneous rocks are formed from cooled magma.
Rocks are divided into three main classes.
Describing a process
Plutonic rocks form as magma cools slowly under
the ground.
Volcanic rocks form as lava cools rapidly on the surface.
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1. How are rocks used?
In the past, stone was used to make buildings,
bridges, city walls, aqueducts, roads, etc.
Today, most modern constructions are not made
of stone. However, they usually contain some
form of rock.
– Ceramic materials are made of clay. They are
used for tiles, bricks, and bathroom pieces
like sinks and toilets.
• Decoration. Granite and marble are the most
popular. They are used for sculptures, floors,
kitchen countertops, etc. They are easy to carve
and polish to a smooth, shiny finish.
• Construction materials. Granite, limestone
and slate are strong, decorative, and provide
good insulation. They are used to make walls
and roofs. They also serve as raw materials to
manufacture other products.
• Containers. Clay is used to make pottery and
china. After the pieces are decorated, they are
glazed and fired. This makes them much stronger.
– Cement is made of limestone and clays.
It is used to make concrete. Concrete is
used for roads, bridges, dams and entire
buildings.
– Plaster is made of gypsum and other
ingredients. It is used on interior walls.
A
Stonehenge, in England,
is made of sandstone.
E
Many statues and monuments
are made of marble.
• Fuels. Coal and oil are used in transportation,
industry, heating and to produce electricity.
• Chemical industry. Oil is used to make
plastics, paints, fertilizers, synthetic fibres and
many other products.
B
The Roman aqueduct in
Segovia is made of granite.
C
Many buildings are decorated
with stone.
F
Clay is used to make plates
and pottery.
D
G
Concrete, glass and metals are
made from rock.
H
Refineries process oil into fuel. Plastics are made from oil.
Activities
Did you know that...?
1. Match each photo with one of the uses of rocks.
The Great Pyramid of Giza,
in Egypt, was built mostly
of limestone - more than
1,300,000 blocks!
2. Make a list of the uses of rocks. Use the text above.
3. Oil has more uses than most other rocks. Investigate
“products made from oil” on the Internet. Make a list.
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2. What are rocks?
The solid part of the Earth is made up of rocks. Rocks are any
natural, inorganic material made up of minerals.
Some Monomineralic Rocks
Mineral
Some rocks are made of a single substance. They are called
monomineralic rocks. Others can be found in liquid form,
for example, oil.
Rock
clay minerals
clay
halite
salt
calcite
calcite / limestone
quartz
quartzite
How are rocks classified?
Rocks are divided into three main classes: igneous, sedimentary
and metamorphic.
• Igneous rocks are formed from cooled magma. Magma is
molten rocky material below the Earth’s surface.
• Sedimentary rocks are formed by the accumulation and
compaction of sediment, for example, clay, sand or rock
fragments.
• Metamorphic rocks are formed from other rocks by the effects
of heat and pressure. Forces inside the Earth cause a “parent
rock” to change into another type of rock, without melting.
Did you know that...?
Igneous rock is named
after the Latin word “ignis”
meaning “fire”.
Igneous rock. These rocks are
formed by minerals joined together.
In granite it is easy to see the
various components.
Sedimentary rock. Conglomerate.
Metamorphic rock. Slate.
Activities
4. What are the three types of rock? Define them in
your notebook.
5. What is the difference between minerals and
rocks? Check your answer by looking at Unit 10.
mantle
crust
external core
internal core
Composition of the Earth
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3. What are sedimentary rocks?
Sedimentary rocks are classified into three groups:
detrital, chemical and organic.
Did you know that...?
Detrital rocks are made up of fragments of other
rocks that are stuck together.
Oil and coal are called fossil fuels.They
are the most important energy resources
for the planet.
Chemical sedimentary rocks are made of mineral
crystals from oceans, lakes and groundwater that have
dissolved in water.
Organic sedimentary rocks are made of plant and
animal remains which have been transformed into
minerals.
Chemical
Formed by
6. Observe pieces of detrital rocks using a
magnifying glass.
Make drawings to show the differences.
7. Describe a rock from the table.
Your partner guesses which one.
Properties
Conglomerate
Fragments of rock
and some sand
Round or angular
fragments
Sandstone
Small grains of sand
Grains break off
if scratched
Clay
Very small grains
Different colours.
Smells like wet earth
when wet
Limestone
(Many types)
Chemical reactions.
All contain calcium
carbonate.
Reacts to acids
by producing bubbles
Gypsum
Evaporation of the
water in deposits
Rock salt
Very soft.
Can be scratched with
a fingernail
Tastes salty
Coal
Remains of land
vegetation
Soft, black.
Burns easily
Oil
Remains of marine plants
and animals
Thick, black liquid
Organic
Classification of Sedimentary Rocks
Detrital
Common
sedimentary rocks
Activities
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4. How are sedimentary rocks formed?
The formation of sedimentary rocks begins with the accumulation and
consolidation of sediment or of rock fragments.
Sedimentary rocks are made up of fragments of other rocks.
The deposition of these sediments in layers, in lakes or seas, takes
place over millions of years. The deposited sediments are transformed
into compact, cohesive rocks. Rocks are fragmented by:
Weathering. Rocks at the surface of the Earth are broken up by
the action of atmospheric phenomena (changes in temperature,
rain, acid rain), or by the activities of plants and animals.
Erosion. These broken fragments of rocks are swept away by running
water, glaciers, waves or wind.
After heavy rains, the rivers transport mud, clay, sand and stones to the valleys.
Strata in sedimentary rock can be
horizontal or folded. As the Earth's crust
moves, the layers of rock get folded up.
The layers of sediment build up over
millions of years to form different
stratas of sedimentary rocks.
How are fossils formed?
Sedimentary rocks sometimes
contain remains of living things
that lived millions of years ago.
These remains are called
fossils. Fossils become part of
the rocks during the processes
of compaction and cementation
of sediments. Fossils provide
invaluable information about
the history of life on Earth.
120
Tree trunks and leaf fossils can show
the vegetation that coal comes from.
Ammonites are marine molluscs which
lived during the Mesozoic period.
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Rock fragments join to form rock by two processes:
Compaction. The weight of successive layers of sediment compacts
the sediments more. This pressure reduces the spaces between the
fragments and squeezes out the water. As a result, salt crystals are
formed.
Activities
8. Where can you find
examples of rock erosion
in your country? Choose
an example and say what
natural phenomena
caused the erosion.
9. How are fossils formed?
Make a series of drawings
to show the process.
Deposition
of sediments
10. What two processes
transform soft, wet
sediment into
sedimentary rock?
Compaction
Cementation. The rock fragments are stuck together with the salt
crystal which formed when the water was eliminated.
Each layer of sediments is transformed into a layer of sedimentary
rock. This layer is called a stratum (plural: strata).
11. Summarise the
information about coal
and oil. Complete the
chart.
Coal
& Oil
Similarities
Differences
Pressure
fragment
mineral deposits
Cementation
How are organic sedimentary rocks formed?
Two kinds of sedimentary rock are made up
of organic material: coal and oil. Coal is made
of terrestrial vegetation. Oil is made of marine
plant and animal remains.
• Coal. Millions of years ago, vegetation
accumulated in swamps. Eventually,
the vegetation was buried in the Earth’s
crust, without air. Then, heat, pressure and
bacteria changed it into coal. This type of rock
is found in continental environments such
as forests.
• Oil. Some sedimentary
rocks contain oil.
Millions of years ago,
microscopic marine
animals and plants
(plankton) fell to the bottom of the sea.
Sediment accumulated on top of this organic
material. The material was buried underground
without air. Eventually, heat, pressure and
bacteria slowly changed the organic material
into oil.
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5. How are igneous rocks formed?
Plutonic rocks: slow
cooling, large crystals.
Igneous rocks are formed as a result of the cooling and
solidification of magma.
Magma is the melted, rocky material from below the Earth’s
crust or mantle. Magma consists of silicates, water and gases
at high temperature. Lava is magma on the Earth´s surface.
There are two types of igneous rocks:
• Plutonic (intrusive) rocks form as magma cools slowly
under the ground over thousands of years. As a result, the
mineral crystals are large.
• Volcanic (extrusive) rocks form as lava cools rapidly on the
surface of the Earth. As a result, the mineral crystals are tiny.
• Large, visible crystals
Granite
• The most common rock in the continental crust
• Many colours – pink to grey and black
• Very hard and strong
• Heavy and hard
Basalt
Volcanic rocks: quick cooling, tiny crystals, vitreous.
As a result, the crystals are not visible.
COMMON IGNEOUS ROCKS
Formed by the solidification of magma
12. Look up plutonic in an
encyclopedia or on the Internet.
Where does the word come
from?
13. Research: What is the difference
between magma and lava?
14. In which type of rock can you see
minerals most clearly? Why?
• Made up of quartz, feldspars and small quantities
of mica and other minerals
• Dark or black colour
• It may contain olivine crystals
• It may have a few bubble holes
• The most common rock on the ocean floors
• Mostly light colours
Pumice
• Light weight and floats in water
• Spongy texture from bubble holes
• Black and smooth
Obsidian
• Looks like black glass
• The edges can cut
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Activities
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6. How are metamorphic rocks formed?
Metamorphism is a slow process which occurs deep in the Earth.
The effects of temperature and pressure change the parent rock
into metamorphic rock.
Activities
15. Do igneous or metamorphic
rocks contain fossils?
Why or why not?
Metamorphic rocks are formed deep within the Earth by the
effects of intense heat and pressure on sedimentary, igneous or
other metamorphic rocks.
16. Draw pictures of sedimentary,
igneous and metamorphic
rocks. Write the name
on the back. Distribute the
pictures. Say if your rock is
sedimentary, igneous or
metamorphic.
These rocks do not melt, but the minerals inside them are
changed by heat and pressure. The rocks become hard and
compact. Metamorphic rocks rarely have fossils.
The formation of metamorphic rocks
sedimentary
rock
Foliated
Non-foliated
Classification
of metamorphic rocks
Common
metamorphic rocks
metamorphic
rock
Appearance
igneous
rock
magma
Properties
Slate
Usually black,
slightly shiny
because of the
presence of mica
Hard, but can be separated
into thin layers or sheets
(foliation)
Marble
Many different
colours. Often with
veins
Does not separate into layers.
Marble reacts with acids,
such as vinegar or
hydrochloric acid, producing
CO2 bubbles
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7. What is the rock cycle?
The rock cycle is a set of processes which form, change and recycle
rocks over time. These processes can take thousands or even millions
of years.
The rock cycle is similar to the recycling process for glass. Used
glass is transported from recycling bins to factories. There, it is
crushed and melted to make new glass. Glass can be used and
recycled many times.
A similar recycling process occurs with rocks. On the Earth’s
surface, weathering and erosion break down and transport rocks.
Under the Earth’s surface, rocks go through processes which
change them. As a result, they become new rocks. The cycle
is continuous.
Rocky landscape, Cappadocia, Turkey
The rock cycle
F
F
and
pre
ss
ur
e
F
magma
F
me
Sedimentary rocks
124
g
lin
coo
co
mp
ac
t ing
ing
F
F
F
el t
wea
t
m
he
r
F
hea
t
re
su
es
pr
nd
g
lt in
ing
Metamorphic rocks
F
sediments
ta
me
weat
her
ing
he
a
g
l t in
we
a th
erin
g
F
Igneous rocks
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Hands on
Investigating weathering and sedimentation
1. Chemical weathering
Chemical weathering occurs when rock
components react chemically with a substance
and are broken down.
Prediction. Vinegar is an acid. What do you think
will happen if you put it on the rock sample?
Materials
a piece of chalk or limestone
a glass jar
a balloon
some vinegar
Procedure
2. Physical weathering and sedimentation
Physical weathering breaks down rocks into
fragments. The deposition of these fragments in
layers over millions of years results in compact,
sedimentary rock.
Prediction. Which rock fragments will be in the
bottom layers and which the top layers?
Materials
a plastic bottle with a screw-on top
0.5 L water
small and medium-sized stones
sand
a. Put the rock into the jar.
Procedure
b. Add a few drops of vinegar.
a. Put the stones, sand and water in the bottle.
c. Stretch the balloon over the top of the jar.
b. Shake the bottle vigorously for one minute.
Observation
c. Wait for the solid matter to settle. Figure 2.
a. Wait and watch carefully. Figure 1.
Observation
b. Take notes to answer these questions.
What happens to the rock?
What happens to the balloon?
a. Observe the layers and draw a picture:
– Which stones are on the bottom?
And on the top?
b. Why did the layers form this way?
Conclusions. What does this experiment tell you
about weathering?
Hint: What acids do you find in the air or water?
Conclusion. What does this experiment tell you
about sedimentation?
Figure 1
Figure 2
Activities
17. Collect rock samples in your area.
Which ones are sedimentary rocks?
18. Research on the Internet how limestone caves
are formed. Is this process caused by physical
or chemical weathering?
How can you tell?
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Activities
19. Copy and label the diagram to show the stages of
erosion / weathering.
24. Clay and granite are rocks. Clay is soft and fragile.
Granite is strong and hard. Can you explain why?
25. Study the photographs. Identify the rocks: marble
or granite. Which is made up of only one mineral?
A
20. In volcanic eruptions, large amounts of gases
escape into the atmosphere. Where do they come
from?
21. Copy and label the stages of the rock cycle.
F
F
F
27. Are there any sedimentary rocks made up
of granite, an igneous rock? Think and explain
your answer. See the rock cycle diagram.
29. What is metamorphism? What two factors
produce it? What do you call the rocks which
result from this process?
F
F
F
26. What type of rock can burn? Explain your answers.
28. Compare the origin of metamorphic rocks and the
origin of igneous rocks.
F
F
B
F
30. How can a metamorphic rock become an
igneous rock?
31. Can a sedimentary rock be transformed into
another sedimentary rock?
F
32. If an igneous rock is under great pressure, what
could happen?
22. Observe samples of sandstone and clay under
a stereoscopic microscope or magnifying glass.
a. What differences can you see?
b. Can you see minerals in one or both rocks?
c. Observe other rocks, such as conglomerate,
granite or limestone. Draw pictures of them.
d. Write a brief description of your pictures.
23. What is the difference between rock salt and sea
salt?
126
33. Imagine your school wants to buy a sign to place
outside. You have information on two different signs:
one made of limestone and one made of granite.
Which one is better? Select the best sign, and write
a report. Give reasons for your selection.
34. Blocks of stone are often used to build walls, and
stone tiles are used for roofs. The most common
rocks used for these purposes are slate and granite.
Which one is used for walls? Which is used for
roofs? Explain your answer.
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What should you know?
11
Rocks are formed by minerals. If the composition of the rock consists of only one mineral, the rock is called
monomineralic. Rocks are classified into three types according to how they are formed:
• Sedimentary rocks. Formed by the accumulation of compacted sediment.
• Igneous rocks. Made of magma which has cooled.
• Metamorphic rocks. Formed by high pressure and temperature. They are always in a solid state.
The rock cycle is the combination of processes that rock and sediments undergo on the Earth’s surface and
in its crust.
Some of the main uses of rock are: construction materials, decoration, containers, fuels, the chemical industry.
Igneous
rocks
Igneous rocks are made from magma: a mixture of melted rock
and gases. There are two types.They can be:
• Plutonic. Slowly solidified deep in the Earth.
Crystallized minerals are apparent. For example, granite.
• Volcanic. Solidified quickly on the exterior
of the Earth’s crust. Homogeneous appearance,
not crystalline. Basalt, pumice and obsidian.
ROCKS
Sedimentary
rocks
Sedimentary rocks are usually found in layers, called strata.
There are three types:
• Detrital. Formed by the combination of fragments of different
rocks and minerals. Conglomerate, sandstone and clay.
• Chemical. Sedimentary rocks are made of mineral crystals
from oceans, lakes and groundwater that have dissolved in
water. Limestone, gypsum, salt.
• Organic. These are formed by the accumulation
of organic material. Coal and oil. These are known as fossil fuels.
Metamorphic
rock
Metamorphism is the process of changes produced in solid
rock by high temperatures and pressure. Metamorphic rock
can be:
• Foliated. These can be separated, cleaved, into layers.
For example, slate, schist and gneiss.
• Non-foliated. These can be broken into irregular shapes.
For example marble, and quartzite.
Projects
INVESTIGATE: Can some rock float? Drop a piece of pumice in water.
a. Does the pumice float or sink?
b. Observe the pumice through a magnifying glass. What can you say about the structure?
c. Is pumice sedimentary, metamorphic or igneous rock? How is it formed? What causes the holes?
WEB TASK: How many active volcanoes are there on Earth?
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It’s elementary!
Currently, more than 110 different chemical elements have been identified. Over 90 elements are found in
nature. The rest are created only in laboratories as artificial elements. All these elements are classified in the
Periodic Table of Elements according to their properties.
The first ten elements
atomic symbol
1
H
F
F
name
of the
element
F
F
atomic
number
Hydrogen
Black - solid
Blue - liquid
Red - gas
Purple - artificial
1
H
1
3
2
H
Be
Hydrogen
4
Li
Be
Lithium
Beryllium
Hydrogen is used
as rocket fuel.
Li
Hydrogen, hydrogen everywhere!
About 90 % of the atoms in the Universe are
hydrogen, about 9 % are helium, and all the
other elements account for less than 1 %.
128
Lithium is used
for batteries.
Beryllium is used for structural
components of space craft.
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Boron is used in fireworks
to provide a distinctive green
colour, and in rockets for ignition.
He
Helium is mixed with oxygen
and is used by deep sea divers.
Hard diamonds and soft
graphite (found in pencil lead)
are both forms of carbon.
Ne
Neon is used for
advertising signs.
2
He
Helium
5
N
6
7
8
9
10
B
C
N
O
F
Ne
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Nitrogen in the soil is
necessary for plant growth.
O
Plants and animals need oxygen
for respiration. Oxygen is used for
patients with respiratory problems.
F
Fluorine is present in
toothpaste. It helps
prevent dental cavities.
Activity
1. Turn to the Periodic Table, page 152. Choose another element and research its uses.
As a class, make a poster of different elements and their uses in everyday life.
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UNIT
12 Matter and
its properties
What do you remember?
• What is matter?
• What unit of measurement is used to show the mass of matter?
And to measure the volume?
• What instrument do you use to measure the sides of a patio?
What units would you use?
Content objectives
Key language
In this unit, you will …
Comparing
• Understand what matter is
Iron has more mass. It is denser than wood.
Measuring
• Learn how to measure the
properties of matter
13.5 g per cubic centimetre. One milligram. Minus 459 degrees.
• Create a graph to show the
relationship between two variables
Two scales are used to measure temperature.
Time is measured in seconds.
130
Making impersonal statements
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1. What is matter?
Everything that takes up space and has mass is matter.
Therefore, everything around us is matter.
• General properties. These are the properties common
to all matter: mass, volume, weight and density.
• Specific properties. These are the characteristics that
differentiate one kind of matter from another. They are
colour, shape, size, texture, hardness, etc. They can be
used to identify and describe matter.
Air is matter
A
B
Balance two inflated balloons on a cane. (A) Then,
burst one of the balloons. The balloons are no longer
balanced. (B) This happens because the inflated
balloon contains air, so it has greater mass than the
burst balloon. Air has mass and occupies space,
therefore it is matter.
The books you read and the pencils you write with are matter.
The water you drink and the air you breathe are matter.
The International System of Measurements
To measure matter, many types of units can be used.
To compare measurements, however, everyone needs to
use the same units.
The most common system is the International
System of Units. There are seven base units. All other units
are a combination of these base units.
• Base units are used to measure length, mass, time etc.
These units are the metre, the kilogram and
the second, etc.
Some base units
Unit
Symbol
Length
Mass
Time
Temperature
metre
kilogram
second
kelvin
m
kg
s
K
• Derived units are obtained from a combination of the
base units. They are used to measure surface area,
volume, speed and density, etc. These units are the
square metre, cubic metre, metre per second, etc.
Did you know that...?
In the past, people used their
hands to measure an object,
or steps to measure the
length of a field.
Activities
1. What are the general properties of all
matter?
2. You can’t see air. Explain why is it
matter.
3. How long is this book? And how
wide? Which unit of measurement
would you use in the International
System of Units?
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2. What is length?
Multiples and submultiples of a metre
Length is the distance between two points.
Length is a base unit. In the International System of Units,
length is measured in metres.
Unit and symbol
Equivalent
millimetre (mm)
1,000 mm 1 mk
centimetre (cm)
100 cm 1 m
Did you know that...?
metre (m)
1m
1,000 m 1 km
kilometre (km)
This bar made of platinum and iridium was used as
the International Prototype to define the metre as
the international unit of length. It is displayed in the
International Bureau of Weights and
Measures, Paris.
Multiples and submultiples
of a square metre
Surface area is the space occupied by the length and width of
a body. It is a derived unit from length.
In the International System of Units, surface is measured in
square metres (m2).
Equivalent
square millimetre
(mm2)
1,000,000 mm2 1m2
square centimetre
(cm2)
10,000 cm2 1 m2
square metre (m2)
1m2
square kilometre
(km2)
1,000,000 m2 1km2
F
3. What is surface area?
Unit name
How is surface area measured?
To calculate the surface area of:
G
height
• Regular shaped objects.
Use the mathematical
equation corresponding
to the shape.
G
F
base
Surface area base length height
2
• Irregular-shaped objects.
Divide the irregular shape into
regular ones, and calculate the
area of each one. Then, add
these areas together to
calculate the total (estimation).
132
• Circular objects. Use multiplied by the square
of the radius: r2.
G
Radius
Surface area r 2
F
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4. What is volume?
Volume
of the object
G
F
The volume of a solid is the amount of space it
occupies. It is a derived unit from length.
Volume is measured in cubic metres (m3).
To measure the volume of:
• Regular geometric solids. Use the corresponding
mathematical formula. For example, to find the
volume of a box, multiply the base (length x width)
by the height.
• Liquids. Use a measuring cylinder to measure
the volume.
Initial volume
• Gases. Fill a measuring cylinder with water. Place it
upside down in a dish of water. Mark the water level
in the cylinder: initial volume. Blow air through a
tube into the cylinder. The air displaces some water.
Mark the new water level: final volume. The
difference between the two levels is the volume of
gas added to the cylinder.
Final volume
Capacity is the amount of liquid a container can hold
when it is full. For example, a bowl can hold more
water than a cup. Capacity is measured in litres (L).
Volume of
the gas
Measuring the volume of a gas
Capacity
The volume of a liquid can be calculated by measuring
the capacity of its container.
F
Measuring the volume of an irregular object
G
• Irregular-shaped solids. Use a measuring cylinder
to measure the volume. Submerge the body in
water, then measure the amount of water displaced.
Multiples and submultiples of a litre
Unit and symbol
Equivalence in litres
Litre (L)
1L
Decilitre (dL)
0.1 L
Centilitre (cL)
0.01 L
Millilitre (mL)
0.001 L
Equivalences between volume and capacity
Volume
1 m3
Capacity
1,000 L
3
1L
3
1 mL
1 dm
1 cm
3
1 mm
0.001 mL
Activities
4. What is the capacity of a container
with a volume of 3.4 cm3?
5. How many 250 mL bottles do you need
to fill a tank with a capacity of 10 L?
Perfume is sold in small bottles because it is very expensive.
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5. What is mass?
Mass is the amount of matter in a body. Mass is a base unit. Mass
is measured in kilograms (kg). Scales are used to measure mass.
Multiples and submultiples of a kilogram
Unit and symbol
Equivalence in kilograms
ton (t)
1,000 kg
kilogram (kg)
1 kg
1kg 1,000 g
gram (g)
decigram (dg)
1g
centigram (cg)
1g 100 cg
milligram (mg)
1 g 1,000 mg
10 dg
This prototype of the kilogram is in the
International Bureau of Weights and
Measures in Paris. The kilogram is a
unit of mass.
A
B
C
Traditional scales compare mass with a standard weight. To do this, place the body to be weighed in a
saucer (A). Add weights to the other saucer (B) until they are balanced (C).
Activities
6. A gold chain was weighed using the following weights:
– one 100 g weight
– two 1 g weights
– one 500 mg weight
Can you calculate the mass of the chain in grams and milligrams?
7. A box of biscuits weighing 1 kg costs 3 €.
A box weighing 250 g costs 1 €.
Read and calculate:
The 1 kg box of biscuits is
times bigger than the 250 g box.
How much money do you save if you buy the big box?
134
This electronic scale can measure
mass to one hundredth of a gram.
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6. What is density?
Density is the relationship between the mass and the volume
of a body, that is, how concentrated the mass is in a specific volume.
Density is measured in kg/m3 or g/cm3.
Iron has a higher density than wood. These two blocks, one of iron,
and one of wood, have the same volume. The block of iron has
more mass, or amount of matter, so it is harder to move. The block
of iron feels heavy for its size.
The mass of one litre of oil is 900 g.
easy to move
→
hard to move
→ → →
The relationship between mass and volume:
• The greater the mass is, the greater the density.
• The greater the volume is, the smaller the density.
Density is a specific property of matter. It helps differentiate one
substance from another.
Density mass
The mass of one litre of water is 1,000 g.
Did you know that...?
volume
Generally speaking, solids have a higher density than liquids.
Liquids have a higher density than gases. For example, air weighs
very little because it has little mass: it feels light for its size.
Activities
Oil floats on water because it
is less dense.
For the same
volume of oil and
water, water has
more matter than
oil. This is the
property of density.
8. Which of the substances in the table on the right float on water?
Why do the others sink?
Densities of some substances
9. These two bodies have the
same mass: the crosses
represent particles of mass.
Which of them has the
highest density? Explain.
x
x
x
x
x
x
A
x
10. These two bodies have the
same volume, but different
mass.
Which body has the highest
density?
x
x
x
x
B
C
x
x
x
D
Substance
Density (g/cm3)
Water
1.0
Oil
0.9
Petrol
0.7
Lead
11.3
Iron
7.9
Mercury
13.5
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7. What are temperature and time?
What is temperature?
Temperature is used to measure the thermal
state of a body. This measurement is related to
the body’s internal state.
Temperature is related to the amount of heat a
body gives off or absorbs. A hot body will
heat a cold one until they are both the
same temperature.
Thermometers are used to measure the
temperature of bodies.
In the International System of Units, the kelvin
(K) is the unit for temperature. Another unit,
degrees Celsius (°C) is used frequently. Some
countries, (especially the United States of
America) use another measurement,
Fahrenheit (ºF). Here are some equivalents:
Temperature scales
kelvin
Celsius
Fahrenheit
Unit (symbol)
kelvin (K)
degree
Celsius (°C)
degree
Fahrenheit (°F)
Boiling point of water
373.15
100
212
Melting point of ice
273.15
0
32
Absolute zero
0.
Temperature does not depend on the
amount of matter. For example, imagine that
the temperature of the water in a glass is
60 ºC. If you pour half of the water into one
glass and half in another, the temperature in
each one will still be 60 ºC.
What is time?
273.15
Penguins are much warmer
than the place they live in.
Their feathers stop them
losing heat.
459.67
Did you know that...?
The following units are also used to measure time:
60 seconds = 1 minute (min)
1 hour (h) = 60 minutes
1 day (d) = 24 hours
7 days = 1 week
365 days = 1 year (366 days in a leap year)
100 years = 1 century
Everyone is aware of the passing of time.
Even without a watch, it is easy to tell when
this class is going to end. The position of the
Moon or the Sun indicates if it will soon be
daytime or nighttime.
Activities
Time is used to measure the passing of events.
In the International System of Units, time is
measured in seconds (s).
11. Convert these temperatures into degrees Celsius.
(ºC +273 = K)
a. 285 K b. 290 K c. 254 K
12. How many things can you list related to measuring
time? Don’t forget “school timetable”.
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Hands on
Analysing results. Using graphs.
A graph can be used to analyse the data from an
experiment. A graph also shows the relationship
between two variables.
thermometer
water
Graphs show how one base quantity varies
in comparison with another. For example,
the temperature of a mass of water will
increase when it is heated.
To see how the temperature
increases, heat a glass with 500
mL of water. Measure the
temperature every
2 minutes.
Time (min)
Temperature (°C)
00
018
01
018
03
032
05
046
07
060
09
074
11
088
13
100
15
100
Follow these steps to draw the graph:
100
– Write the time scale on the horizontal
axis (min).
– Write the temperature scale on the
vertical axis (ºC).
2. Mark the points on the graph. Mark
points on the graph where the time values
intersect with the temperature values.
3. Draw a line to join all the points.
Use a ruler to make the line straight.
Temperature (°C)
1. Draw the coordinate axes on squared paper.
80
60
40
20
0
0
1
3
5
7
9
11
13
15
Time (min)
Activities
13. Describe the graph. Why do you think the line begins and ends horizontally?
14. Do the same experiment with 300 mL of water.
a. Stir the water so the temperature is the same in all parts of the glass.
b. Measure the temperature of the water every two minutes.
c. Make a table and draw a graph.
d. Compare the two graphs. Are there any differences?
e. Does the amount of water affect the time it takes to heat up?
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Activities
24. Look at the picture. Which of the two substances
is denser? Why?
15. Measure the surface of a piece of paper
and give the result using the correct units of
measurement.
16. Which multiples and submultiples of the metre would
you use to calculate the following measurements?
a.
b.
c.
d.
The distance between two towns.
The diameter of the head of a nail.
The length of your pen.
The length of the classroom.
B
A
17. Research on the Internet different types of calendar.
Which calendar do you use in your country?
18. Copy and complete the following table using the
formula to calculate density.
Substance
Mass (kg)
Volume (m2)
Cedar wood
57,000
100
Water
Lead
Aluminum
96º alcohol
570
1
22,600
Gold
Mercury
Density
(kg/m3)
1,000
2
3
54,400
4
5,400
2
25. A 3 L container of olive oil has a mass of 2.7 kg.
Calculate the density of olive oil.
26. Oil spills occur when the cargo from an oil tanker
pours into the ocean due to an accident, for
example, Prestige, in 2002. Taking into account that
the density of oil is less than that of sea water, will
the oil float or sink? What consequences do oil
spills have on the environment?
19,300
27. What base quantities are also general properties
of matter?
1
800
19. Give the following measurements in centimetres.
a. 320 mm
b. 3.5 m
c. 2 km
20. If you mix water with oil, it separates into two
layers. Which liquid floats on top?
28. Research the history of the different ways to
measure temperature. Where do the names
Fahrenheit, Celsius and Kelvin come from?
29. Copy and complete the table:
Length Mass Time
3
Remember: the density of water is 1 g/cm , and the
density of oil is 0.9 g/cm3.
Temper- Surface
Volume
ature
area
Unit
Symbol
21. The density of iron is 7.9 g/cm3. If a nail made of
iron has a mass of 20 g, what is its volume?
22. Measure the surface area of a piece of paper. Give
your answer using the International System of Units.
23. A school wants to build a new sports field. It needs
to include:
– a football pitch measuring 100 m x 100 m
– a basketball court measuring 18 m x 15 m
– a tennis court measuring 23.77 m x 8.23 m
How many square metres are needed for the sports field?
138
ºC
K
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MATTER
What should you know?
Properties
Matter is anything that has mass and volume.
The properties of matter are:
• General properties, common to all matter:
– Mass
– Volume
• Specific properties: those which differentiate one
substance from another.
Base
quantities
Base quantities are all independent. They are
measured in base units.
• Length is the distance between two points.
The unit for length in the International System
of Units is the metre (m).
• Mass is the amount of matter in a body.
The unit for mass in the International System
of Units is the kilogram (kg).
• Temperature is the thermal state of a body.
The unit for temperature in the International
System of Units is the kelvin (K).
• Time measures the passing of events.
The unit for time in the International System
of Units is the second (s).
Derived
quantities
Mathematical combinations of base units are called
derived units.
• Surface area is the extension of a body in two
dimensions. The unit for surface area in the
International System of Units is the square
metre (m2).
• Volume is the space occupied by a body.
The unit for volume is the cubic metre (m3).
• Density is the relationship between the mass and
the volume of a body. The unit for density is the
kilogram per cubic metre (kg/m3).
12
Projects
EXPERIMENT: Think up an experiment to prove the hypothesis: A digital watch measures
time more accurately than an hour glass.
Describe: a. The equipment you used.
b. Procedures.
c. Conclusions.
WEB TASK: How warm is 50 degrees Fahrenheit? How big is a 30 inch TV screen?
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UNIT
13 Everything is matter
What do you remember?
• What are icebergs and glaciers made of?
• What state of matter is ice?
• Can water exist in more than one state?
• Is sea water made up of one substance or several?
• What is fresh water made of?
Content objectives
Key language
In this unit you will …
Describing a process
• Differentiate changes of state of matter
When a liquid is heated, it boils.
When a solid is heated, the particles gain energy.
• Recognise the conditions in which changes
occur
Making generalisations
• Differentiate pure substances and mixtures
Most common substances are mixtures.
Most plastics are made from petroleum.
• Evaluate the need for recycling waste
Describing
• Draw conclusions from examining the
components of a mixture
A pure substance has only one component.
A compound contains two or more elements.
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1. Which are the states of matter?
Matter can exist in three physical states: solid, liquid and gas.
Matter normally exists in one state in nature. However, water can
exist naturally in all three states: ice, water and water vapour.
Solids have a fixed shape
if no pressure is exerted.
Shape
Volume
Liquids have no fixed shape.
They adapt to a container.
Gases have no fixed shape.
They occupy all available space.
Solids
Liquids
Gases
Hold shape
Shape of container
Shape of container
* except for water
– Fixed volume
– Fixed volume
– Solids expand
– Liquids expand
if heated, or contract if cooled*
if heated or contract if cooled.
– Volume of container
– Gases expand to
occupy all available space.
Fluidity
– Solids cannot flow.
– Can flow. They spread if not
in a container.
– Can flow. They spread if not
in a container.
Density
– Usually have a high density:
many particles
in a small volume
– Quite high density:
a lot of particles in a small
volume
– Low density: few particles
in a large volume
Compressibility
– Difficult to compress
– Quite difficult to compress
– Easy to compress
The states of matter according
to particle theory
Activities
•
1. In which of the states of matter are the particles
closest together? Why is it very difficult to compress
solids and liquids?
Matter is made up of tiny particles.
Between them are empty spaces.
• The particles within matter are in constant
motion.
2. Describe how the particles move in solids, liquids
and gases.
• Temperature affects the speed of particles.
3. Why do solids generally have a higher density than
liquids, and liquids a higher density than gases?
• There are forces which attract the particles.
Solids
The particles are very
close together, held by
strong forces of
attraction.
They vibrate
but do not
change
position.
Liquids
The particles are close together,
held by weak forces
of attraction.
They have some
freedom of
movement.
They can flow
and slide easily.
Gases
The particles are far apart and
move quickly in all
directions. The
particles have no
force of attraction.
They collide
with each other.
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fusion
vaporisation
solidification
condensation
2. How can matter change its state?
Solid to liquid
• When a solid is heated, the particles gain more energy
and move more. The forces of attraction between the
particles are weakened.
• At a certain temperature, the particles have enough
energy to break free from their positions. When a solid
changes into a liquid, the process is called melting or
fusion.
• The reverse process, when a liquid is cooled and changes
to a solid, is called solidification.
• The temperature of a substance at fusion and
solidification is always the same one.
Liquid to gas
Did you know that...?
Above its boiling point a substance
is a gas.
Between its melting point and boiling
point a substance is a liquid.
Below its melting point a substance is
a solid.
Activities
4. Study the diagram. Which arrows
(red or blue) indicate changes of state
produced by heating? Which arrows
correspond to changes produced
by cooling?
liquid
• When a liquid is heated to a certain temperature, it
boils. The particles have enough energy to break free
from their positions. When a liquid evaporates into a
gas, the process is called vaporisation.
• The reverse process, when a gas changes into a liquid,
is called condensation.
Solid to gas
• When a solid changes into a gas without first becoming
a liquid, the process is called sublimation. For example,
naphthalene balls change slowly into a gas.
• When a gas changes directly into a solid, the process is
called regressive sublimation. For example, snowflakes
change from water vapour into solid snow.
142
solid
fu
sio
n
so
lid
ifi
ca
tio
n
Particles of matter do not change from one state to another.
They only change their arrangement or their energy. When
matter changes state, no mass is lost.
va
po
ris
at
co
io
nd
n
en
sa
gas
tio
n
sublimation
regressive sublimation
5. 50 g of iron is melted. How much liquid
iron is produced? Why is this?
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3. What are mixtures?
Most common substances are mixtures. For example, the
air in the atmosphere is a mixture of various gases.
Mixtures that appear uniform are called homogeneous.
Mixtures where more than one part is distinguishable are
called heterogeneous.
Heterogeneous mixtures
In some mixtures, the components are clearly
distinguishable. For example, most rocks contain a mixture
of different minerals.
Granite is a heterogeneous mixture. It is
composed of minerals that are clearly
distinguishable (each colour is a different
mineral).
Steel is a homogeneous mixture.
It is made from iron and carbon.
Homogeneous mixtures
In homogeneous mixtures, you cannot distinguish each
component with the naked eye. They have a uniform
composition. For example, sea water, air, and vinegar.
Activities
What is a solution?
6. Copy and complete the chart. Add
more examples.
A solution is any homogeneous mixture. Solutions are
usually liquid mixtures, that is, liquids with solid
substances, such as water with sugar. The sugar is dissolved
evenly throughout the liquid. The simplest solutions
consist of two components: a solvent and a solute.
Mixture
air
Components
Homogeneous /
Heterogeneous
nitrogen, oxygen, argon homogeneous
steel
iron and carbon
granite
various minerals
However, solutions can be solid, liquid or gaseous:
– Solids within solids: alloys are special solutions:
all their components are solids. For example, steel (iron
mixed with carbon).
– Liquid within liquid: alcohol dissolved in water.
– Solid within liquid: salt dissolved in water.
– Gas within liquid: CO2 dissolved in fizzy drinks.
– Gas within gas: air (nitrogen, oxygen, argon, etc.)
Solvent. The liquid
part (often water)
7. Look in your kitchen for mixtures and
label them homogeneous or
heterogeneous:
mayonnaise, tomato sauce, paper,
pineapple juice, honey, a drink of
coffee, coke, chicken soup, fruit
yogurt.
Solute.
The dissolved
substance
Solution
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4. What are pure substances?
hydrogen
oxygen
A pure substance has only one component. It has a
homogeneous look. It has unique properties that
characterise it, for example, its density. These properties
distinguish it from every other substance.
Pure substances in nature can be either chemical
compounds or elements.
• Chemical compounds. A chemical compound
consists of two or more elements joined up. The
atoms are from different elements. Compounds
have a fixed composition: water is always made up
of two atoms of hydrogen and one atom of oxygen.
It can be expressed as H2O.
water
Water is a compound. It is made up of two parts
hydrogen to one part oxygen. Twice as much hydrogen
as oxygen is obtained when water is broken down.
• Chemical elements. A chemical element cannot be
broken down into simpler substances. About ninety
chemical elements can be found in nature.
Hydrogen and oxygen are chemical elements.
5. What are physical and chemical changes?
A physical change does not change the composition of the substance. In a chemical change, where there is
a chemical reaction, the substance is changed to a new kind of substance.
Activities
8.
9.
Physical change. If you cut
paper into tiny pieces, each
piece is still paper. When water
changes into ice or vapour, it is
still water.
144
Chemical change. When rust
appears on a piece of iron, a new
substance has been formed: iron
oxide. When paper is burned, you
can no longer see the pieces of
paper. A new substance has been
formed: ash.
What are the differences
between pure substances
and homogeneous mixtures.
How are they similar?
Classify these things:
homogeneous or
heterogeneous mixtures,
or pure substances:
a. sand and water
b. oxygen
c. iron
d. water
e. milk and chocolate powder
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Hands on
Checking a hypothesis. Separating mixtures
Using the filtration method
The filtration method is good for separating an
insoluble solid from a liquid. (An insoluble substance
does not dissolve in water.)
You are going to separate a mixture of water and
sand using this method.
The liquid passes through the filter, but the solid
particles cannot go through.
Materials
– water
– a beaker
– a funnel
– some filter paper
– a container for the mixture of water and sand
1. Put the funnel into the beaker. Place the filter
paper in the funnel.
2. Pour the mixture into the filter paper.
3. Remove the sand that has stayed behind in the
filter paper.
Using the decanting method
The decanting method is useful for separating
a heterogeneous mixture of two liquids that have
a different density.
You are going to separate a mixture of water and oil
using this method.
Materials
– water
– oil
– spoon
– a container for the mixture of water and oil
1. Leave the mixture to rest until the particles of the
liquid with the least density (oil) settle on top of
the particles with the highest density (water).
2. Use a spoon to separate the liquid that is at the
top of the beaker.
Activities
10. Does sand dissolve in water?
Is a mixture of sand and water homogeneous or
heterogeneous?
11. Copy and complete the text.
Sand
dissolve in water. When you mix
sand and water you get a
mixture.
Sugar
in water to form a solution.
A solution is a
mixture.
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6. What are synthetic materials?
Synthetic materials do not exist in nature. They are obtained from
natural substances which are transformed by chemical processes.
Activities
Fibre optic is a fibre made of glass or plastic. It is a long, fine tube
which light travels along.
12. What materials would
you use to make the
following products?
a. a boat
b. a modern office
building
c. parts of an aeroplane
d. a strong container to
hold water
e. a cable for
telephones
Say why in each case.
Carbon fibre is made up of mainly carbon atoms. It is an extremely
thin fibre. Each fibre is incredibly strong. The fibres are woven
together to create a very resistant material.
13. What properties of
carbon fibre make it ideal
for making a bicycle?
Synthetic materials are used to manufacture many products in
modern, industrialised societies because of their special properties.
Some of the most popular synthetic materials are:
Plastic. Most plastics are made from petroleum. There are many
different kinds, used to make a multitude of things.
Glass is made from silica.
Fibreglass is made from extremely fine fibres of glass, woven
together.
Some properties of synthetic materials
Material
Properties
Plastic
Glass
– impermeable
– fragile, but hard
– light, flexible
– resistant
Fibreglass
Fibre optics
– excellent
conductor of light
– light
– does not rust
– flexible and
strong
– lets light through
– does not rust
– does not rust
– elastic
– does not rust
Used for
multiple uses
Carbon fibre is strong but elastic.
It has many uses in aviation
146
Carbon fibre
– resistant
– does not rust
multiple uses
boats, car bodies
Equipment for water sports is often
made of fibre glass
cables for
telephones,
computers
cars, bikes, tennis
rackets, aeroplanes
Fibre optics can conduct vast quantities
of light or information at very high speed
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7. Why is recycling important?
Solid waste: example
Every year, modern societies generate more and more
rubbish. Urban solid waste is unwanted solid and
semi-solid materials from homes, commerce and
industry.
organic matter 30 %
paper 25 %
textiles 10 %
This waste can be harmful to the environment. Some
of it is toxic. It needs to be treated or recycled.
What can you do to help?
You can reduce solid waste in the home, and recycle
some of it. Recycled materials can be transformed
into new raw materials.
plastics 7 %
glass 10 %
metals 8 %
other 10 %
DO
Activities
Reuse materials: plastic bags, writing paper.
14. Copy and complete the table about waste
in your home.
Recycle paper, glass, tins and plastic.
Organic
Take old medicines, paints and batteries to
vegetables
leaves
collection dumps. Use rechargable batteries.
DON’T
Buy things with a lot of unnecessary packaging.
Dump rubbish on the beach or in the countryside.
Toxic
medicines
paints
Recyclable
bottles
newspapers
15. Make a Do / Don’t poster about how to help
reduce solid urban waste.
16. Investigate how urban solid waste is removed
in your own area.
What happens to recycled waste?
transport
waste collection
gl
as
s
domestic
consumption
co
m
po
st
pl
as
tic
m
et
al
waste
collection
rubbish
dump
raw materials
processing
and
manufacturing
pa
pe
r
ss
ce
ro
p
g
lin
yc
c
re
toxic waste
incineration
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Activities
17. Read and classify: solid, liquid or gas.
a. oxygen
b. water
c. granite
d. hydrogen
e. oil
f. steam
g. salt
h. iron
B
-cornflakes and milk
-butter and salt
-water and oil
-water and ink
23. Can mixtures be compounds? Why or why not?
18. Identify: element, compound, mixture.
A
22. Could you make a solution of the following
substances? Say why or why not in each case.
Hint: A chemical compound consists of two or more
elements joined up.
C
24. Copy and complete the following phrases.
19. Copy and complete the table with the properties of
the three different states.
Shape
Volume
Flows / does
not flow
Solids
a.
b.
c.
d.
The change from solid to liquid is called…
The change from gas to liquid is called…
The change from liquid to gas is called…
The change from liquid to solid is called…
25. Indicate the solvent, the solute and the solution in
this drawing.
C
A
Liquids
B
Gases
20. Give reasons for your classification in activity 17.
1. It flows easily.
2. It is easy to compress.
3. It cannot be compressed.
4. It has no fixed shape.
5. It has a fixed shape.
6. It has a fixed volume and shape.
7. It takes the shape of its container.
8. It can spread out into a space.
Example: a-4. Oxygen is a gas: it has no fixed shape.
21. Classify the changes: physical or chemical.
Give a reason.
a. Paper is burned and changes into ashes.
b. A rusty piece of metal.
c. Clothes drying in the Sun.
d. Lava cools down and solidifies.
e. Water is broken down into hydrogen
and oxygen.
It’s a
148
chemical
physical
change because the substance
is the same.
changes.
26. All substances can be found in any one of the three
states of matter, if the conditions are right.
a. Is it is possible to find iron in a liquid state on Earth?
b. Is it possible to find water in a gaseous state?
27. Draw how you think particles of air are organised
inside a container. Represent the air particles with
dots. Then, draw the particles again after half the
air has been removed.
28. Cartons are made with several layers of cardboard
and polyethylene. The polyethylene is in contact
with the liquid. It is a light plastic that does not let
in air, humidity or bacteria. Cardboard makes the
container harder.
a. Why is polyethylene a good material to store food?
b. What would happen if the container were made
only of cardboard?
29. If you wash up a glass and leave it to dry, what has
happened to the water on the glass? Would it dry
faster in a cold room or a warm one? Why? What is
the name of this process?
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What should you know?
Matter can exist in three different physical states:
• Solid: Fixed shape and volume. High density.
• Liquid: No fixed shape. Fixed volume. It can flow.
Quite high density.
• Gas: No fixed shape. No fixed volume. It can flow
and be compressed. Low density.
A substance can change from one state into another.
F
Physical
states
13
Liquid
G
fu
si
so
on
lid
ifi
ca
tio
n
n
io
at
ris
n
po
tio
va
sa
en
nd
co
G
sublimation
EVERYTHING IS MATTER
G
F
Solid
F
Gas
regressive sublimation
Particle
theory
• Matter is made up of tiny particles, surrounded by
empty spaces.
• The particles within matter are in constant motion.
• There are forces which attract the particles.
Particle theory describes changes from one state into
another.
Mixtures
Matter can be classified by its appearance as:
• Heterogeneous: the appearance is not uniform. The
components can be distinguished.
• Homogeneous: appearance is uniform. The
components cannot be distinguished.
Most common substances are mixtures.
Solutions are homogeneous mixtures of two or more
substances, made up of:
• a solvent: the most abundant component.
• a solute: the least abundant part of a solution.
Pure
substances
There are two types:
• Chemical compounds: Can be broken down chemically into simpler substances.
• Elements: Cannot be broken down into simpler substances
Projects
INVESTIGATE: Research other methods for separating mixtures. Display the results in a poster.
Use diagrams and explanations.
WEB TASK: What is the fourth state of matter? Investigate.
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UNIT
14 Atoms and elements
What do you remember?
• What is all matter composed of?
• What gases are there in the air?
• Which gas predominates?
• Which gas do living things breathe?
Content objectives
Key language
In this unit, you will …
Describing
• Learn about the basic components of matter
Magnesium is a silvery white metal.
Silicon is a solid, non-metal substance.
• Identify elements in the PeriodicTable
Indicating location
• Differentiate atoms, elements, molecules
and crystals
Magnesium is found in minerals.
Carbon is found on the Earth´s crust.
• Interpret some chemical formulas
Comparing
• Prepare a scientific report
Hydrogen is the most abundant gas in the Universe.
Oxygen is the most abundant element on Earth.
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1. What is matter made of?
electrons
protons
All matter is made up of atoms. An atom is the smallest
particle of matter which can exist alone. It has all the
properties of matter to which it belongs.
Atoms are so small, they cannot be seen under a
microscope. For example, one gram of copper contains
more than nine thousand trillion atoms.
The structure of an atom
At the centre of an atom is a core called a nucleus. The
nucleus is made up of particles called protons and
neutrons.
nucleus
neutrons
Protons have a positive charge (⫹). Neutrons have no
charge. This means that the nucleus has a positive charge.
Extremely small particles called electrons orbit the
nucleus. Electrons have a negative charge (⫺). They are
attracted to the positively charged protons in the nucleus.
The structure of an atom
Carbon atom
Nitrogen atom
Between the nucleus and the electrons there is nothing, so
most of an atom is empty.
The atomic number
The atomic number of an atom is the number of protons
in the nucleus. Each atom has a unique atomic number.
6 protons
7 protons
Carbon atoms and nitrogen atoms have different
2. What are elements?
atomic numbers: 6 and 7, respectively. As a result, they
are different elements with very different properties.
An element is a substance that contains one type of atom.
It cannot be broken down into anything simpler by
chemical reaction.
The atoms of one element are different to the atoms of
every other element. For example, oxygen is made up
only of oxygen atoms. Hydrogen is made up only of
hydrogen atoms. Consequently, an atom is the smallest
part of an element.
Did you know that...?
All matter is made up of the atoms of
one or more elements. There are about
90 different elements found in nature.
Activities
1. In what ways are some atoms different from others?
2. Why is most of the structure of an atom empty?
3. Draw a carbon atom and label nucleus, protons,
neutrons and electrons.
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3. How are elements classified?
All the elements found on Earth are classified in the Periodic Table of
Elements. Each element is represented by a symbol consisting of one or
two letters.
Black - solid
Blue - liquid
Red - gas
Purple - artificial
For example, the symbol for hydrogen is H and for magnesium it is Mg.
atomic
number
1
2
3
4
5
6
7
8
9
10
11
Mg
name
of the
element
The Periodic Table of Elements
12
13
12
F
Magnesium
F
14
F
In the Periodic Table, the elements are grouped according to their atomic
number. Elements with similar chemical properties are in the same column.
15
16
atomic
symbol
17
1
2
H
He
Hydrogen
Helium
1
3
4
8
9
10
C
N
O
F
Ne
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
12
13
14
15
16
17
18
Na
Mg
Al
Si
P
S
Cl
Ar
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
Sulphur
Chlorine
Argon
20
21
22
23
K
Ca
Sc
Ti
Potassium
Calcium
Scandium
Titanium
4
37
38
39
40
24
41
42
Y
Zr
Nb
Rubidium
Strontium
Yttrium
Zirconium
Niobium
57
72
Cr
V
Sr
56
25
26
Mn
Vanadium Chromium Manganese
Rb
55
73
43
Mo
Tc
27
75
29
30
31
32
33
34
35
36
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
44
Ru
Molybdenum Technetium Ruthenium
74
28
76
45
46
47
48
49
50
51
52
53
54
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
77
78
79
80
81
82
83
84
85
86
Cs
Ba
La
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
Cesium
Barium
Lanthanum
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
87
7
7
B
19
6
6
Be
11
5
5
Li
2
3
18
88
89
104
105
106
Fr
Ra
Ac
Francium
Radium
Actinium Rutherfordium Dubnium Seaborgium
Rf
58
LANTHANIDE
SERIES
F
ACTINIDE
SERIES
F
6
59
Ce
Cerium
90
7
Db
Sg
60
Pr
107
Hs
Bohrium
Hassium
61
Nd
108
Bh
62
Pm Sm
Praseodymium Neodymium Promethium Samarium
91
92
93
Th
Pa
U
Thorium
Protactinium
Uranium
Np
94
Pu
109
Mt
110
Ds
111
Rg
Meitnerium Darmstadtium Roentgenium
63
Eu
64
Gd
Europium Gadolinium
95
96
Am Cm
Neptunium Plutonium Americium
Curium
65
Tb
Terbium
97
Bk
66
67
Dy
68
Ho
Dysprosium Holmium
98
99
Cf
69
Yb
Lu
Erbium
Thulium
Ytterbium
Lutetium
Fm
101
Md
102
No
4. Find platinum, gold and mercury in the periodic table. How many protons does each element have?
5. Can you find any other metals in the Periodic Table?
7. Say the letters of a symbol. Your partner says the element.
152
103
Lr
Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium
Activities
6. How are elements grouped in this Periodic Table?
71
Tm
100
Es
70
Er
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4. How are atoms organised?
The noble gases are monoatomic. In others
words, they exist as single atoms: they do not
join up with each other to form molecules.
The noble gases are helium, neon, argon,
krypton, xenon and radon.
Atoms are organised in different ways.
Did you know that...?
Helium, a noble gas,
is lighter than air.
It is used to fill party balloons.
The atoms of most elements join up with each
other to form molecules. Molecules are made
up of two or more atoms. There are two types
of molecules:
• Simple molecules consist of two or more
atoms of the same element joined together.
• Compound molecules consist of a
combination of different atoms joined
together.
Compound molecule
Water (H2O)
Simple molecule
Oxygen (O2)
Crystals consist of atoms or molecules
arranged in a regular, organised structure.
Each crystal has a different shape and unique
properties. There are two types of crystals:
• Simple crystals consist of groups of atoms
of the same element joined together in an
organised structure. For example, metals.
• Compound crystals consist of groups of
atoms from different elements joined
together. For example, common salt is
sodium chloride.
O2 is an oxygen
molecule made
up of two
oxygen atoms.
A water molecule
is H2O: two
hydrogen atoms
joined with one
oxygen atom.
Every chemical element has its own specific
properties. The combination of elements
produces millions of compound substances
with very different properties.
Activities
8. Look at the periodic table. How many noble
gases are there? What are their atomic
symbols?
9. Compare the main characteristics of atoms,
molecules and crystals. Make a table.
10. Draw pictures to illustrate an atom, an
element and a molecule.
Compound crystal
Common salt is made from
sodium and chloride atoms
bonded together.
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5. What is a chemical formula?
Oxygen molecule (O2)
Each element has its own chemical symbol: oxygen is O, calcium
is Ca. To describe molecules, a chemical formula is used.
A chemical formula consists of chemical symbols and numbers
to indicate how many atoms of each element make up a molecule.
two
oxygen atoms
For example, the formula for carbon monoxide is CO. This
means that each molecule of carbon monoxide consists of one
carbon atom joined to one oxygen atom.
• Simple substances. The formula indicates the molecule of
the substance. For example, O2 is the formula for the
substance with molecules made up of two oxygen atoms
joined together.
F
O2
number of atoms
F
symbol for the element
• Compound substances. The formula indicates which
elements make up the molecule. For example, a water
molecule, H2O, consists of one atom of oxygen joined to two
atoms of hydrogen.
F
F
H2O
number of atoms
oxygen
atom
F
F
symbols for each elements
• Crystals. Some elements form simple crystals. In this case,
the chemical formula is the same as for the chemical symbol
for the element. For example, carbon crystals: C.
hydrogen
atoms
Water molecule (H2O)
• Compound crystals. The chemical formula indicates the
elements and their proportions within the crystal.
F
F
NaCl
chlorine
atom
proportion of each
F
F
symbols for elements
sodium
atom
• Some chemical formulae are more complicated. For example,
the formula for sodium sulphate is Na2SO4. It indicates that
sodium sulphate consists of two sodium atoms, one sulphur
atom and four oxygen atoms.
Sodium chloride
molecule
(Na Cl)
Activities
11. Copy the table and complete.
Name
154
Chemical formula
iron oxide
Fe2 O3
silver oxide
Ag2 O
aluminum oxide
Al2 O3
Atoms:
name and number
12. Sucrose is the chemical name for sugar.
Its formula is C12H22O11.
a. How many elements make up this substance?
b. What is the name of each element?
c. How many atoms of each element are there
in sucrose?
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6. Which elements can be found in nature?
There are more than 110 elements in the Periodic Table,
92 are found in nature. All the others are man-made.
Universe
hydrogen 83.9 %
Hydrogen and helium are the most abundant
elements in the Universe. The stars are made up
mainly of these two elements.
Hydrogen (H2) is a gas. It makes up 83% of the
Universe. It is found in the atmosphere, water, rocks…
Helium (He) is a noble gas. It makes up 15.9% of
matter in the Universe, but there is very little on Earth.
other elements 0.2 %
helium 15.9 %
Living things
hydrogen 63 %
others 0.6 %
Carbon, hydrogen, oxygen and nitrogen form 95%
of all living things.
Atoms of carbon combine with many other atoms
to form a wide variety of molecules in living things.
Some elements can be found both in living beings,
in water and on the Earth’s crust. However, they
form different compounds.
oxygen 25.5 %
nitrogen 1.4 %
Nitrogen (N2) is a gas formed by molecules. It is
the most abundant gas in the Earth’s atmosphere.
It is a basic compound of proteins. There is
nitrogen in the soil.
oxygen 47 %
Oxygen (O2) is a gas formed by molecules. It is the
most abundant element on Earth. It is found in the
atmosphere in water, rocks and organic substances.
carbon 9.5 %
Earth’s crust
silicon 28 %
aluminium
7.9 %
Carbon (C) is the basis of all organic compounds
in living things. It is found on the Earth’s crust as
coal, graphite ...
others
1.69 %
iron
4.5 %
calcium 3.5 %
sodium 2.5 %
potassium 2.5 %
carbon 0.19 %
hydrogen 0.22 %
magnesium 2.2 %
Did you know that...?
Living things are made
up of about twenty elements.
Activities
13. Compare the pie charts.
a. Which is the most homogeneous? In which
is there more diversity?
b. Ask questions about the charts: for example,
Where is there more hydrogen? In the
Universe or the Earth’s crust?
Is there any silicon in living things?
14. Carbon is not the most abundant element in
living things. Which element is?
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7. Why are elements
important?
In the Earth´s crust
The most abundant elements which form the rocks
and minerals of the Earth’s crust are silicon,
aluminium, iron, magnesium and calcium.
• Silicon (Si) is a solid, non-metal substance.
It is generally found as a compound: the most
common is quartz. It combines with oxygen to
form silicates.
• Aluminium (Al) is a soft, light metal. It is only
found as a compound and is obtained from
bauxite. Aluminium alloys are used to make
aeroplanes, ships, etc.
• Iron (Fe) is a grey metal. It is generally found as
a compound. It combines with oxygen to form
hematite and magnetite. Iron is present in your
blood.
Magnesium is used in the composition of fireworks.
Did you know
that...?
Pure silicon is used
to make microchips
for computers.
• Magnesium (Mg) a silvery metal. It is found in
minerals such as olivine. It burns very easily
with a very bright, white flame.
• Calcium (Ca) is a greyish white metal, found
only in compounds. Calcium carbonate,
(CaCO3), is found in seashells and egg shells.
In sea water
The most abundant elements in sea water are
chlorine, sodium and potassium.
• Chlorine (Cl) is a yellowish green gas at room
temperature. It combines with metals to form
salts. Chlorine is used to disinfect water in
swimming pools.
• Sodium (Na) is a soft, shiny metal. It is only
found in compounds. It reacts easily with the
oxygen in the air. Sodium chloride (NaCl) is
common salt.
• Potassium (K) is a soft, shiny metal. It is only
found in compounds like potassium chloride
(KCl).
Sodium and potassium are also present in living
things. They help muscle contraction and the
functions of the nervous system.
156
Water is disinfected with chlorine.
Activities
15. Which element can you find in: fireworks,
sea shells, aeroplanes, and blood?
16. Classify the elements on this page in a table.
Metal
Non metal
17. Describe an element. Your partner guesses
which one.
It is a soft, shiny metal.
It is found in common salt.
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Hands on
Writing a fact file: Elements
Research an element from the Periodic Table.
Then, write up your fact file. Follow this outline to
help you.
1. Chemical composition.
Choose an element. What is its atomic symbol?
Draw the atom. What is its chemical formula?
Some interesting elements:
copper, iron, phosphorus, sulphur, fluorine, iodine.
4. Why it is important.
Is it important in living things, or in the
Earth’s crust?
Give some facts and examples.
2. Description.
Write a physical description of the substance. Is it
solid, liquid or gas? Is it a metal or a non-metal?
5. Some important uses.
What is this element or its compounds used for?
What other forms does it have?
3. Where it is found in nature.
Is it found as a simple substance or a compound
substance? Is it abundant or rare?
Calcium Fact File
Calcium, Ca has an atomic number of 20.
Description
Calcium atom
Calcium is a soft, grey metal.
Where it is found in nature
Calcium is not found as an element in nature.
It is usually found in rocks like limestone or gypsum.
Why it is important
Calcium is the fifth most abundant element in the Earth’s crust.
It is also essential for living things. It is the most common mineral
in the human body. 99 % of this is found in bones and teeth.
Calcium carbonate (CaCO3) is the main component
of seashells, egg shells and snail shells.
Some important uses
It is used as an antacid for stomach pains.
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Activities
25. Study the diagrams. Different atoms are shown
in different colours.
18. Copy and label this atom:
nucleus
protons
neutrons
electrons
19. Each of these formulas represents a gaseous
substance: (CO) carbon monoxide, (NO) nitrogen
oxide, (C4H10) butane.
A
B
C
D
Explain the meaning of each formula.
20. Write the formula for a substance which contains
two atoms of hydrogen, one atom of sulphur, and
four atoms of oxygen.
21. Carbon monoxide is a gas: CO. Lead is a solid,
heavy metal. Could these substances be found as
molecules or as crystals?
22. What is the difference between an atom and a
molecule?
a. Which drawings correspond to elements?
b. Which drawings correspond to compounds?
Explain your answers.
c. Can you see any molecules? How many atoms
does each have?
26. Copy and complete the table.
Element
23. Use the Periodic Table to make a list of the
elements that are most abundant in:
a. The Universe.
b. The Earth’s crust.
24. Copy and complete the summary for each element.
Compound
Copper (Cu)
Sulphur
dioxide (SO2)
Sulphuric
acid (H2SO4)
Helium (He)
Elements in nature
Nitrogen (N2)
The Earth’s crust
In sea water
27. Copy and complete the table.
Silicon
compound / formula
Chlorine
water (H20)
Si
sodium hydroxide (NaOH)
non-metal
sodium sulphate (Na2SO4)
It is in quartz.
It forms silicates.
calcium carbonate (CaCO3)
158
elements / number of atoms
hydrogen: 2
oxygen: 1
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ATOMS AND ELEMENTS
What should you know?
Atoms
and
elements
Atoms are the smallest particles of a chemical element. They
are made up of a nucleus with protons and neutrons, and
electrons which orbit the nucleus.
• Matter is made up of atoms.
• Elements are formed by equal atoms.
• Compounds consist of two or more different atoms.
There are more than one hundred different elements. They
are classified in the Periodic Table of Elements.
Substances
and formulas
Atoms form different types of substances:
• Monoatomic: the noble gases.
• Molecules: the union of two or more atoms.
– Simple molecules: formed by identical atoms:
gases (O2, N2, H2)
– Compound molecules: formed by different atoms:
compounds in gas or liquid form (H2O, CO2).
• Crystals: many atoms joined together in an organised
structure.
– Simple crystals: formed by identical atoms. Example: metals.
– Compound crystals: formed by different atoms. Example:
solid substances like sodium chloride (NaCl).
Elements in
nature
• Hydrogen. A gas formed by molecules (H2). It is the most
abundant gas in the Universe.
• Helium. A gas formed by atoms (He). It is the second most
abundant gas in the Universe.
• Nitrogen. A gas formed by molecules (N2). It is the most
abundant gas in the Earth’s atmosphere.
• Oxygen. A gas formed by molecules (O2). It is the most
abundant element on Earth, and the second most
abundant in the atmosphere.
• Carbon is the basis of organic compounds.
• Silicon is only found as a compound in nature. It is the
main component of silicates.
• Aluminium, iron, magnesium and calcium are metals
which are abundant in minerals and rocks.
• Chlorine, magnesium, sodium and potassium dissolve in
water. They make up the ‘salt’ in sea water.
14
Universe
Living
things
Earth’s
crust
Projects
for living things. Why?
• Why do we use fertilizers with nitrogen?
• Where does nitrogen in the soil come from?
• Can plants live in soil without nitrogen?
WEB TASK: Research the world of nanotechnology.
INVESTIGATE: Nitrogen in soil is very important
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Vocabulary
1
The Universe
asteroids
rocky bodies which orbit the stars.
astronomical unit the distance from the Earth to the
Sun: approximately 150 million kilometres.
galaxies a vast collection of stars, dust and gases, held
together by gravitational attraction.
geocentric theory proposed that the Earth was the
centre of the Universe.
heliocentric theory proposed that the Sun was at the
centre of the Universe.
light-year the distance light travels in one year:
about 9.5 trillion km.
Milky Way the galaxy where our Solar System is.
orbit a curved path which a celestial body follows
in its revolution around another celestial body.
2
Planet Earth
atmosphere the layer of gases which envelops the
Earth. Nitrogen and oxygen are the most abundant.
biosphere the part of the Earth’s surface, sea and air
that is inhabited by living things.
core the centre of the Earth, below the mantle.
Its temperature is over 4,000°C.
crust the outer layer of the Earth’s surface. It is
divided into continental crust and oceanic crust.
equinox the time of the year when day and night are
exactly the same length.
geosphere the solid part of the Earth which includes
the lithosphere, the mantle and the core.
hydrosphere
all the water on Earth.
lithosphere the upper 100 km of the geosphere. It is
is made up of the crust and the upper mantle.
lunar eclipse when the Moon passes behind the
Earth, so the Earth prevents sunlight from reaching
the Moon.
mantle the middle layer of the Earth, below the crust.
It is made up of rock. The temperature is from 1,000 to
4,000ºC, so some areas are melted rock.
revolution the elliptical path taken by one body
around another. The Earth revolves around the Sun.
rotation the Earth rotates on its axis. The axis is tilted
23.5 degrees. This rotation creates day and night.
160
solar eclipse when the Moon passes between the Sun
and the Earth, and blocks off the sunlight.
water cycle the movement of water around, over,
and through the Earth: evaporation, condensation,
precipitation, surface runoff and infiltration.
3
Living things
autotrophs living things which produce the organic
substances they need from inorganic substances. Plants,
algae and some bacteria are autotrophs.
cell membrane the outer covering of a cell. The cell
membrane keeps the cell together and controls what
passes in and out of it.
chloroplasts organelles with a green pigment,
chlorophyll, which absorbs the Sun’s energy to
elaborate organic matter during photosynthesis.
cytoplasm the inside of a cell where many of the
chemical reactions take place.
eukaryotic cells cells which have a nucleus,
separated from the cytoplasm by the nuclear
membrane.
heterotrophs living things which obtain nutrition
from organic matter which is already elaborated.
Animals, fungi, and all protozoa are heterotrophs.
inorganic substances things which contain no
carbon. They are present in living things and non-living
things: water and mineral salts.
organelles small structures in the cytoplasm
responsible for respiration, making and storing
nutrients, etc.
organic substances substances exclusive to living
things. Carbon is the principal element. Organic
substances include: glucides, lipids, proteins and
nucleic acids.
nutrition all the processes which enable living things
to obtain the energy and matter they need to live.
photosynthesis the process through which plants
obtain nutrition.
prokaryotic cells cells with no nucleus or nuclear
membrane. Genetic material is dispersed throughout
the cytoplasm. They are simpler than eukaryotic cells.
species the first level of classification for living things.
A group of living things which are physically similar.
They reproduce and usually have fertile descendants.
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Invertebrates
annelids invertebrates with soft, cylindrical bodies
divided into segments, with organs in each segment.
Most breathe through gills.
arthropods the largest and most varied group of
living things: more than one million species. They live
in sea water, fresh water and on land.
cephalopods a group of molluscs. They have tentacles,
but no shell. For example: squid, cuttlefish and octopus.
cnidaria jellyfish, corals and sea anemones. They
have a soft body, with only one opening
and a mouth surrounded by tentacles.
crustaceans a group of arthropods with 10 legs, with
usually an aquatic habitat. For example: lobster or crab.
echinoderms invertebrate animals which live on the sea
bed. For example, sea urchins, starfish and sea cucumbers.
gastropods a group of molluscs. Gastropods have a
spiral-shaped shell with a single valve. For example,
snails, sea snails and slugs. Slugs have no shell.
poikilotherms cold-blooded animals. They cannot
regulate their body temperature, so are warm or cold
depending on the environment.
reptiles vertebrate animals with bodies covered with
hard scales. They are poikilothermal and most of them
are oviparous and carnivorous.
viviparous animals that give birth to live young.
Development starts in the mother’s body. The babies
feed on the mother’s milk.
6
The plant and fungi
kingdoms
angiosperm flowering plants which have seeds inside
a real fruit.
dispersal a stage of plant reproduction. The ripe fruit
falls off the plant or releases the seeds.
ferns small non-flowering plants. Ferns are vascular.
They have roots, stems, and leaves called fronds.
molluscs a group of invertebrate animals with a soft
body divided into head, body mass and foot. For
example, squid, mussels, oysters, slugs and snails.
fertilisation a stage of plant reproduction. Pollen
reaches the stigma, penetrates it, and fertilises the
ovules inside the ovary.
myriapods a group of arthropods with worm-like
bodies and many legs. They are terrestrial. For example,
centipede and scolopendra.
fungi have eukaryotic cells and are heterotrophic.
Fungi are made up of hyphae, which group together to
form the mycelium.
oviparous animals that lay eggs. Eggs are laid by
the female and develop outside the body.
germination the last stage of plant reproduction.
Seeds germinate producing a tiny shoot and root.
platyhelminths invertebrates with long, flat, soft
bodies. They have neither legs nor respiratory or
digestive systems. Many are parasites.
polyp cnidaria bodies shaped like a tube with the
opening at the top. For example, corals and sea
anemones.
porifera invertebrate animals without organs.
Sponges belong to this group.
5
Vertebrates
amphibians vertebrate animals. Their skin is moist
and has no covering. They have four legs and are
poikilothermal. They undergo metamorphosis.
homeotherms warm-blooded animals: capable
of keeping their body temperature constant.
gymnosperm one kind of flowering plant. They have
seeds inside a false fruit, like a pinecone.
mosses small, non-flowering plants. They are nonvascular. They have no true roots, stems or leaves.
pollination the first stage of plant reproduction.
Wind and insects transport pollen from one flower to
another.
stomata
microscopic pores on the underside of a leaf.
transpiration process by which excess water is expelled
through leaf stomata in the form of water vapour.
vascular plants with conductor vessels to distribute
water and nutrients.
yeasts unicellular fungi. Some types are used to make
bread, wine, beer, etc.
7
The simplest living things
mammals a group of vertebrate animals. Their bodies
are covered with hair or fur. They are homeothermal
and have mammary glands.
algae unicellular or multicellular autotrophs. They
live in salt and fresh water.
ovoviviparous animals that are born from an egg.
The egg develops inside the female.
bacteria microscopic, prokaryotic organisms. They
belong to the Monera kingdom.
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a group of protozoa with hair-like organs.
flagellates one of the groups of protozoa. They move
with a flagellum (tail).
protoctist unicellular and multicellular living things.
They are eukaryotes and have no tissues. The Protoctist
kingdom includes protozoa and algae.
9
The hydrosphere
condensation the process in which water vapour
changes to liquid.
currents movement of large bodies of water by
prevailing winds.
protozoa unicellular and heterotrophic living
things. Some are parasites, and cause illnesses.
evaporation the process of the water cycle in which
liquid water changes to a gas (water vapour).
rhizopods protozoa with pseudopods (projections
of the cell cytoplasm).
evapotranspiration when water evaporates into the
atmosphere from the leaves and stems of plants.
saprophytes organisms which live on dead or
decomposing matter. They transform organic
substances into inorganic substances.
groundwater
sporozoa
surface runoff when the movement of surface water
across the land forms rivers and streams.
a group of protozoa that cannot move.
vaccines contain dead or weakened microorganisms
from a specific illness. They teach the body how to fight
an illness.
8
The Earth’s atmosphere
acid rain rain with dissolved pollutants such as
sulphur dioxide and nitrogen oxide.
climate describes the characteristic pattern of weather
in an area, over a long period of time.
global warming in the last century, the atmosphere
has warmed between 0.5 and 0.9ºC on average.
greenhouse effect a natural phenomenon, essential
for keeping the temperatures on Earth suitable for life.
CO2 in the atmosphere acts like the glass walls of a
greenhouse. It traps the heat and prevents it from
returning into space.
water located beneath the ground.
infiltration surface water penetrates into the ground.
This occurs more easily if the ground is porous.
tides the rise and fall of water levels due to
gravitational attraction of the Moon and the Sun.
waves occur on the surface of water, caused by the
wind. Wave action causes cliff erosion and creates
beaches.
10
Minerals
hardness measures how a mineral reacts to being
scratched.
impurities small amounts of other substances found
in minerals. These can change some mineral properties.
lustre refers to the way minerals reflect light. It can
be metallic, or non-metalic.
mixtures are made up of different substances of
varying sizes, shapes and colours.
ionosphere the highest and thickest layer of the
atmosphere.
Mohs Scale of Hardness classifies minerals by
hardness. One is soft. Ten is the hardest.
mesosphere a layer of the atmosphere about 40 km
thick. It contains clouds of ice and dust.
non-silicates minerals which contain no silicon:
native elements, oxides, sulphides, carbonates and
halides.
meteorology the study of different atmospheric
variables to make weather predictions.
ozone (O3) a gas which exists throughout the
atmosphere, mainly concentrated in the stratosphere.
It makes up the ozone layer.
stratosphere a layer of the atmosphere about 30 km
thick. There is an increase in temperature from –70ºC
at its lower limit, to 0ºC at its higher limit.
silicates the most abundant minerals on Earth.
They are made up of silicon and oxygen. Some
common silicates are quartz and feldspar.
streak the colour of the powder left when minerals
are scratched.
11
Rocks
troposphere a very thin layer which represents 80%
of the total mass of the atmosphere. Aeroplanes fly at
this level. It is where the greenhouse effect is produced.
cementation the process by which sedimentary rock
is formed from sediments glued together.
weather describes the state of atmospheric
conditions at a certain place, over a short period of
time.
compaction the weight of layers of sediments which
reduces the spaces between the fragments and squeezes
out the water. As a result, salt crystals are formed.
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erosion fragments of rocks are picked up and
transported by running water, glaciers, or wind.
igneous rocks rocks formed from cooled magma.
metamorphic rocks rocks formed from other rocks
by the effects of heat or pressure.
metamorphism a slow process in which temperature
and pressure change parent rock into metamorphic
rock.
organic sedimentary rocks made up of organic
material, fossils. There are two kinds: oil and coal.
plutonic (intrusive) rocks rocks formed as magma
cools slowly under the ground over thousands of years.
rock cycle the processes which form, change and
recycle rocks over millions of years.
sedimentary rocks rocks formed by the
accumulation and compaction of sediment, for
example, clay, sand or rock fragments.
volcanic (extrusive) rocks rocks formed as lava
cools rapidly on the Earth’s surface.
weathering atmospheric phenomena (changes in
temperature, rain, etc.), or the activities of plants and
animals which break up rocks.
12
Matter and its properties
base units used to measure length, mass, time, etc.
capacity the amount of liquid a container can hold
when it is full. Capacity is measured in litres (L).
degrees Celsius a scale used to measure temperature.
0ºC equals 273.15K or 32ºF.
density the relationship between the mass and the
volume of a body. Measured in kg/m3 or g/cm3.
derived units obtained from a combination of the
base units. They are used to measure surface area,
volume, speed, density, etc.
International System of Units (SI) a system which
defines the base and derived units required to measure
the properties of matter.
kelvin one of the scales of the International System of
Units that is used to measure temperature. 0 K equals
–273.15ºC and –459.67ºF.
mass the amount of matter in a body. Mass is
measured in kilograms (kg).
matter all objects that take up space, and have mass.
Everything around us is made of matter.
surface area the extension of a body in two
dimensions, measured in square metres (m2).
volume the amount of space matter occupies. Volume
is measured in cubic metres (m3).
13
Everything is matter
chemical compound a substance containing two
or more elements joined up.
compressibility a property which measures the
difficulty of matter to be compressed.
fusion the process by which a solid changes into a
liquid.
heterogeneous a mixture of substances where more
than one part is distinguishable.
homogeneous a substance which is uniform in
structure and composition.
recycle to transform used materials into new materials.
regressive sublimation the process by which a gas
changes directly into a solid.
solidification the process by which a liquid is cooled
and changes to a solid.
solute in a mixture, the dissolved substance.
solution any homogeneous mixture.
solvent in a mixture, the part where the substance
is dissolved.
sublimation the process by which a solid changes
into a gas, without first becoming a liquid.
vaporisation when a liquid evaporates into a gas.
14
Atoms and elements
atom the smallest particle of matter which can exist
alone. It is made up of a nucleus with protons
and neutrons, and electrons.
atomic number the number of protons in the nucleus
of an atom. This number is different for each atom.
chemical formula symbols which indicate how many
atoms make up a molecule.
crystals consist of atoms or molecules arranged in a
regular, organised structure.
electrons extremely small particles that orbit the
nucleus. They have a negative charge (–) and are
attracted to the positively charged protons in the nucleus.
element a substance that contains just one type of
atom. It cannot be broken down into anything simpler
by chemical reaction.
molecules two or more atoms joined together.
neutrons particles in the nucleus which have no charge.
periodic table of elements a table in which all
elements are grouped with similar elements, with their
symbol and atomic number.
protons particles in the atom’s nucleus, which have
a positive charge.
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Key language
CLASSIFYING
Non-silicates
There are
are classified into
two groups of minerals.
five groups.
How many groups
How are
of non-silicates
minerals
Five.
Into two groups.
are there?
classified?
COMPARING
Planets are
The closest star
bigger than
to Earth is the Sun.
Are planets
bigger than
other celestial bodies.
other celestial bodies?
Ocean trenches are
the deepest areas
The largest plains
of
on
Where
are the largest
plains on the planet?
Ferns
Flowering plants
the oceans.
the planet are under the oceans.
are
bigger than mosses.
more complex.
Which group is bigger, ferns or mosses?
Ferns.
The higher
The higher
a place is,
the altitude,
Where is it colder?
The higher a place is,
Talc
is softer than
apatite.
Is
talc
harder than
the colder
the lower
it will be.
the density of the air.
the colder
apatite?
That box is
four times bigger than this one.
Why does oil float on water?
Because it is less dense.
Hydrogen and helium are
the most abundant
elements
Which are
the most abundant
elements?
it will be.
No, it isn’t.
in the Universe.
DESCRIBING
The Sun
Asteroids
consists mainly of
are
What does the Sun consist of?
Water
There
exists
are
How many states does water exist in?
164
hydrogen and helium.
rocky objects.
What are asteroids?
in three states.
submarine volcanoes in the oceans.
Are there volcanoes in the oceans?
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DESCRIBING
A bacteria
does not have
an organised nucleus.
Does
a bacteria
have an organised nucleus? No, it doesn’t.
Water
Water
is
absorbs heat.
a powerful solvent.
What
are two properties of water? Cohesion and adhesion.
Petroleum
Mica
is
can be scratched
Is
How hard
petroleum a mineral?
is talc?
A pure substance
a rock.
with a fingernail.
No, it’s a rock.
It has a hardness of 1 on the Mohs scale.
has
Is sea water a homogeneous mixture?
only one component.
Yes, it is.
Calcium
is
a greyish white metal.
What is potassium like?
It is a soft, shiny metal.
DESCRIBING A PROCESS
When minerals dissolve in water, raw sap
When pollen penetrates the stigma, ovules
When
are
ovules
Igneous rocks
How
are
is produced.
are fertilised.
fertilised?
When pollen penetrates the stigma.
are formed as a result of
igneons rocks
When paper
When you mix
formed?
is burned,
sand and water,
the solidification of magma.
By the effects of heart and pressure.
it changes into
you get
ashes.
a heterogeneous mixture.
When does sublimation occur? When a solid changes directly into a gas.
EXPRESSING FACTS
Living things
Inorganic substances
What
Do
feed and reproduce.
do not contain
do living things
inorganic substances contain
The Monera kingdom
Most bacteria
carbon.
do?
carbon?
contains
do not produce
They reproduce.
No, they don’t.
unicellular organisms.
their own food.
EXPRESSING AMOUNTS
The Earth’s atmosphere
is about 800 km
high.
How high is the atmosphere?
About 800 km
high.
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EXPRESSING AMOUNTS
68.7% of fresh water
is found
in lakes.
How much salt
What percentage of fresh water
is there in sea water? About 35 grams.
is there on the Earth? Only 3%.
EXPRESSING CAUSE AND RESULT
Water exists in three states
The Earth looks blue
due to
because of
temperature variations.
the water on its surface.
Why does the Earth
look blue?
Because of the water.
They undergo metamorphosis.
As a result,
they develop lungs.
How do amphibians develop lungs?
As a result of
metamorphosis
EXPRESSING CONTRAST
Some arthropods
Most gastropods
are
have
carnivores,
a shell,
but
but
others are herbivores.
slugs don’t.
Do all cephalopods have a shell?
Are all arthropods carnivores?
Most fish are covered with scales.
However,
Do all fish have scales?
Most do. However,
a shark’s skin has denticles.
sharks have denticles.
EXPRESSING DIRECTION
Water filters
Waves transport sand
into
along the coast and
the ground.
out to sea.
Where does water flow?
To the sea, and
into the ground.
EXPRESSING PURPOSE
Water is necessary
Living things need glucose
to transport
to get
all other substances.
energy.
Why is water necessary?
Why do living things need glucose?
To transport
To get
substances.
energy.
Reptiles have hard scales
to keep
them warm.
Why do reptiles have hard scales?
Ceramic materials
are used
for tiles and bricks.
How are rocks used?
Which rock is used for roofs?
GIVING INSTRUCTIONS
Study
Research
166
the constellations.
more about them on the Internet.
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GIVING INSTRUCTIONS
Label
each jar.
Observe
the samples.
INDICATING LOCATION
Magnesium
is found in
minerals.
Where
is
magnesium
found?
In minerals.
MAKING GENERALISATIONS
Most sponges
Some molluscs
live
have
in the sea.
no shell.
Where
do
most sponges
All
Most
plants
gymnosperms
Do
have
are
all plants have roots?
Most rocks
Solutions
contain
can be
live?
roots.
evergreens.
Are
all gymnosperms evergreens?
a mixture of minerals.
solid, liquid or gaseous.
How many states of matter
are there?
Three.
MAKING IMPERSONAL STATEMENTS
Systems
are made up of
several organs.
What
are systems
made up of?
Some bodies
What
are divided
are
their bodies
Some rocks
Sedimentary rocks
How
are
rocks
The volume of a liquid
A thermometer
How
is
into segments.
like?
can be broken into
are found
irregular shapes.
in strata.
classified?
three main classes.
can be calculated
is used
surface area
A series of segments.
measured?
Into
by measuring the container.
to measure temperature.
In square metres (m2).
MEASURING
The court
Density is measured
measures 18 by 15 metres.
in kilograms per cubic metre (Kg/m3).
How cold is that?
How is density measured?
Minus 273.15ºC.
In kilograms per cubic metre.
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Essential Natural Science 1 is a collective work, conceived, designed and created by the Secondary Education
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