Download secondary education 1 eso

SECONDARY EDUCATION 1 ESO
NATURAL SCIENCES
UNIT 5
THE EARTH CRUST
a)
b)
c)
d)
e)
f)
g)
h)
Introduction
Initial Assessment
Contents
Activities
Self-assessment
Other resources: bibliography and resources on the Internet
Reinforcement
Further Study / Investigation Project
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -1-
A/ INTRODUCTION
ALFRED WEGENER: THE EXPLORER
Alfred Lothar Wegener (1880-1930) was a German interdisciplinary scientist who
had early training in astronomy. (Ph.D., University of Berlin, 1904). He became
interested in the new discipline of meteorology. His lectures became a standard
textbook in meteorology, The Thermodynamics of the Atmosphere. Wegener was
part of several expeditions to Greenland to study polar air circulation, when the
existence of a jet stream itself was highly controversial. He died there of exposure in
bitter cold.
Browsing the library at the University of Marburg, where he was teaching in 1911,
Wegener was struck by the occurrence of identical fossils in geological strata that
are now separated by oceans. The accepted explanations or theories at the time
posited land bridges to explain away these anomalies. But Wegener was
increasingly convinced that the continents themselves had shifted away from a
primal single massive supercontinent, which drifted apart about 200 million years
ago, to judge from the fossil evidence. From 1912 he publicly advocated his theory
of "continental drift", arguing that the continents on both sides of the Atlantic Ocean
were drifting apart. In 1915, in The Origin of Continents and Oceans Wegener
published the theory that there had once been a giant supercontinent, which he
named "Pangaea" (meaning "all-Earth") and drew together evidence from various
fields. Expanded editions during the 1920s presented the accumulating evidence.
The last edition, just before his untimely death, revealed the significant observation
that shallower oceans were geologically younger.
Many geologists focused on a lack of a demonstrable mechanism and rejected and
ridiculed Wegener for his ideas, noting that he could not explain how continents
were able to move. Only after the mid-20th century discovery of seafloor spreading
did Wegener receive credit, as an early developer of the theory of plate tectonics. It
took more than 50 years before adequate evidence was acquired and presented to
convince mainstream geologists to acknowledge that the continents were actually in
motion; and the fit between the coasts of Africa and South America was more than
just illusionary. Nevertheless, Wegener's assumed drift rate was ten to a hundred
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -2-
times faster than we now know to be true, and this unreasonable estimate must
have contributed to the resistance to his ideas.
Answer the following questions:
a) Why is Wegener important?
b) Can you explain his theory of “continental drift”?
c) What did he call “Pangaea”?
“The student will …”
1. To differentiate minerals from rocks and to know the properties characteristic of
first.
2. To identify different minerals by its characteristics. To know the procedures
extraction of minerals and their constituent metals.
3. To know the main characteristics that allow to differentiate rocks.
4. To identify by its characteristics the most important rocks. To learn the use that
becomes of rocks.
Sciences Assessment Criteria
Criteria
A: One world
B: Communication in science
C: Knowledge & understanding of science
D: Scientific inquiry
E: Processing data
1-6
1-6
1-6
1-6
1-6
Assessment
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -3-
B/ INITIAL ASSESSMENT
Try to answer the following questions:
1.
a)
b)
c)
Which of the following statements is correct:
Iron comes from a mineral
Iron comes from a rock
Iron comes from oil
2. What are fossils?
3. What is a mineral deposit?
4. Can you explain the following term “non-renewable energy”?
5. Why do some rocks have marine animal fossils on it?
6. What is a volcano?
7. Write down the parts of a volcano
8. Which of the following items are made of rocks or minerals:
Oil
Plastic
Leather
Mercury
Gypsum
Brick
Butter
Iron
Glass
Cotton
9. Which of the following rocks can you recognise immediately?
a) Granite
b) Slate
c) Marble
d) Sandstone
e) Any of them
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -4-
10. Write a “M” next to the terms which are minerals and a “R” to those which
refer to rocks.
a)
b)
c)
d)
e)
f)
g)
Limestone
Marble
Slate
Gypsum
Quartz
Sandstone
Mica
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -5-
C/ CONTENTS
1. The Earth, our planet
1.1 Structure of the Earth
1.1.1
The crust, the mantle and the core
1.1.2
Asthenosphere, lithosphere, mesosphere and endosphere
1.2 Minerals. Types and properties.
2. Rocks
2.1
Igneous rocks
2.2
Sedimentary rocks
2.3
Metamorphic rocks
2.4
The rock cycle
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -6-
D/ ACTIVITIES
1. THE STRUCTURE OF THE EARTH
Work System: Individual
Resources: Digital Text
READ AND LEARN
The Earth is one of the nine planets orbiting the Sun. The Earth was formed around
4600 million years ago. Dust and gas produced in the “Big Bang” came together to
form planets. One of these planets is the Earth. In the beginning the Earth was not
solid, but over time the outside cooled to form a hard rock crust.
1. When was the Earth formed?
2. How was the Earth formed?
3. Can you explain the “Big Bang” theory?
4. What is planetesimal? What is the realtionship between planetesimal and the
formation of the Earth?
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -7-
READ AND LEARN
5. I



The earth consists of several layers. The three main layers are the core, the
mantle and the crust. The earth is surrounded by the atmosphere. The other
layers are: the asthenosphere, the lithosphere, the mesosphere and the
endosphere.




The outer shell of the Earth is called the CRUST
The next layer is called the MANTLE
The next layer is the liquid OUTER CORE
The middle bit is called the solid INNER CORE
The core
The inner part of the earth is the core. This part of the earth is about 2,900 km below
the earth's surface. The core is a dense ball of the elements iron and nickel. It is
divided into two layers, the inner core and the outer core. The inner core - the center
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -8-
of earth - is solid and about 1,250 km thick. The outer core is so hot that the metal is
always molten. The outer core is about 2,200 km thick.
The mantle
The layer above the core is the mantle. It begins about 10 km below the oceanic
crust and about 30 km below the continental crust. The mantle makes up nearly 80
percent of the Earth's total volume.
The crust
The crust lays above the mantle and is the earth's hard outer shell, the surface on
which we are living. In relation with the other layers the crust is much thinner. It
floats upon the softer, denser mantle. The crust is made up of solid material but
these material is not everywhere the same. There is an Oceanic crust and a
continental crust.
1. What is the atmosphere?
2. Explain the following layers of the Earth.
LAYERS
DEFINITION
Lithosphere
Astenosphere
Mesosphere
Endosphere
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -9-
3. What is density? Is density involved in the different layers of the Earth?
4. What is gravity? Is gravity the same in the moon than in the Earth? Why? Why
not?
5. What is a planetesimal?
I CONTINUE LEARNING…
Work System: Individual
Resources: Library books and Digital Text
Tectonic plates
The Earth’s crust is not one solid piece. It is broken into huge slabs or rocks called
tectonic plates. There are two different types of tectonic plate. The lightest and
thickest plates are called continental crust. Continental crust forms the land but
can also extend under the sea.
The second type of tectonic plate is called oceanic crust. Oceanic crust is thinner
but made of heavier rock. Because it is heavy, oceanic crust can be pushed down
into the mantle.
6. What is a tectonic plate?
7. What is the difference between continental and oceanic crust?
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -10-
Work System: In small groups
Resources: Library books, digital text and computer based resources
8.
Find information about the geosphere? Draw a picture to help you.
READ AND LEARN
MINERALS
A mineral is a natural, solid, homogeneous, uniform, crystalline substance. There
are over 2.000 different minerals and in order to classify them we need to study their
properties and characteristics. The study of minerals is called mineralogy.
Minerals have:
Chemical properties. The chemical properties of minerals are due to their
composition.
Physical properties. They depend, most of the times, on the crystalline structure of
the mineral. The most common physical properties are: hardness, appearance,
density.
Other properties of minerals are tenacity, ductibility or malleability and the
capacity to conduct electricity, magnetism, etc.
9. Explain the following terms:
Hardness:
Appearance:
Density:
Tenacity:
Malleability:
10. What is the Mohs scale? Draw and explain the scale. Use the information on
page 97 of your course book.
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -11-
11. What do we refer to when we say that a mineral is uniform?
12.
Look for a picture of quartz and fluorite and stick them on a piece of
paper. Answer the following questions:
a) Describe the colour and the transparency of both minerals.
b) Describe the texture.
READ AND LEARN
CLASSIFICATION OF MINERALS
To be classified as a "true" mineral, a substance must be a solid and have a crystal
structure. It must also be an inorganic, naturally-occurring, homogeneous substance
with a defined chemical composition.
Minerals can be classified as sedimentary, magmatic or metamorphic.
Sedimentary minerals appear through chemical changes in the substances which
form a sediment. Sediments are the remains of rocky materials which are deposited
and, in time, are converted into rocks.
Magmatic minerals are formed by the cooling and solidifying of magma, the melted
rocky material from the deep layers of the Earth.
Metamorphic materials are formed by the transformation of materials due to heat
and the pressure in some areas of the Earth’s crust.
13. Minerals are considered non-renewable resources. Why?
14. In what groups are the following minerals classified?



Quartz, oligist and mica
Graphite and talc
Halite, calcite and gypsum
15. Complete the following concept map:
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -12-
MINERALS
Are classified as
Are defined as substances that are
In which subgroups may be defined according to their
And they have
such as
such as
PURITY
TASTE
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -13-
2. ROCKS
Work System: Individual
Resources: Library books and pages 96 to 98 of your course book
READ AND LEARN
Rock is a naturally occurring aggregate of minerals and/or mineraloids. Rocks are
classified by mineral and chemical composition; the texture of the constituent
particles; and also by the processes that formed them.
THE ROCK CYCLE
Materials from rocks are used over and over again. This is called the rock cycle. It
can take millions of years.
WEATHERING
EROSION
Exposed rock is
weakened by the
weather
The weak surface is
eroded (worn away) by
wind or water
NEW ROCK
Compressed by the
weight above, the bits
join to make new rock
TRANSPORT
The bits are carried off
by wind or water. Or
they just fall
DEPOSITION
The bits are deposited
(dropped) as sediment
such as sand or mud
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -14-
16. What’s the difference between a rock and a mineral?
17. What are the different groups of rocks?
18. Write out the sentences in the correct order, starting with the one which
means “weathering”.
a)
b)
c)
d)
e)
Pieces of rocks are dropped as sediment
Pieces of compressed rock join together
Pieces of rocks are carried off by wind or water
Exposed rocks is weakened by the weather
Pieces of rocks are worn away by wind or water
READ AND LEARN
TYPES OF ROCKS
Igneous rocks are formed from molten magma and are divided into two main
categories: Plutonic rock and Volcanic rock. Plutonic rocks result when the magma
cools and crystallises slowly within the Earth's crust, while Volcanic rocks result from
the magma reaching the surface either as lava.
Sedimentary rocks
Sedimentary rocks are formed by deposition of other rocks or the remain of living
creatures, followed by compaction of the particulate matter and cementation. The
latter can occur at or near the earth's surface, especially in the case of carbonaterich sediments.
Metamorphic rocks
Metamorphic rocks are formed by subjecting any rock type during volcanic activity,
or earth movements. Rocks which come into contact with magma are heated and
turned into another type of rock.
19. What are Plutonic rocks? Name the most important one and explain their
properties.
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -15-
20. What are Volcanic rocks? Name the most important one and explain their
properties.
21. How are sedimentary rocks formed?
22. How are igneous rocks formed?
23. Fill in the following table giving an example of each type of rock.
ROCK
IGNEOUS
SEDIMENTARY
METAMORPHIC
USED FOR
EXAMPLE
24. How is cement made? Explain the process.
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -16-
GLOSSARY OF KEY WORDS
Define the following words. You can add any other important terms that you have
learnt in this unit.

Magma:

Density:

geophysics:

Planetesimal:

Mantle:

Core:

Crust:

Tectonic plate:

Mineral:

Rock:

Hardness:

Mohs scale:

malleability:

Metamorphic:

Chemical change:

Sedimentary:

Weathering:
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -17-
E/ SELF-ASSESSMENT
Name .......................................................................... Group .................
1. Which are the seven layers of the Earth? Draw a picture and label them.
2. What do we use the Mohs scale for?
3. Which layer surrounds the Earth?
4. What’s a mineral?
5. Explain the chemical properties of minerals.
6. Explain the physical properties of minerals.
7. What’s the difference between a mineral and a rock?
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -18-
8. Explain the classification of rocks.
9. Explain with a concept map the rock cycle.
10. What is a tectonic plate?
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -19-
F/ OTHER RESOURCES: BIBLIOGRAPHY AND INTERNET RESOURCES
Sources of information:




Student’s Book Science 1 1º ESO. Unit 7
Cambridge Encyclopaedia
Hutchinson Encyclopaedia
Classroom Library
Software:
 Encarta Encyclopaedia 2000
Internet Resources:
-
Essential Guide to rocks
www.bbc.co.uk/education/rocks
-
USGS Home page
www.usgs.gov
-
International Mineralogical Association
www.ima-mineralogy.org
-
Weathering and Erosion
http://schoolsite.edex.net.uk/192/text/envhome.htm
-
British Geological Survey
http://www.bgs.ac.uk
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -20-
G/ REINFORCEMENT
Name ..............................................................
1. Name
the
layers
of
the
Earth.
Group ................
Draw
a
picture
and
label
2. What is a tectonic plate?
3. What is a mineral?
4. Write down the characteristics of minerals
5. What is the Mohs scale?
6. Explain the classification of rocks?
7. What’s the rock cycle?
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -21-
it.
H/ FURTHER STUDY / INVESTIGATION PROJECT
Choose one of the following topics:
1. The ancient Egyptians used a rock called diorite to make sculptures. Find out:
a) The characteristics of this rock
b) Which type of tools they used to work with this rock.
c) Could we make an Egyptian statue using a rock of the same
composition and properties. Give reasons for your answer.
2. Make a diagram to show the different group of minerals. Include examples and
photographs.
3. Find out the most common rocks in Spain.
Sistema Educativo SEK – Aula Inteligente
Natural Sciences – 1ºESO – Unit 5 -22-