Download Earth and spaces

Earth and space
Unit 6E.1: Earth and Space
Movement of the Earth and
Moon
• Sun, moon, and Earth.
• The movement of the Earth.
• The phases of the Moon and
eclipses
Science skills:
• Observing
By the end of this unit you should know:
•
Sun and stars are sources of light and the sun is
the source of heat too.
•
The moon orbiting the sun causes the Phases of
moon.
•
The causes of tides.
•
What causes the solar eclipse?
•
What causes the lunar eclipse?
•
The effect of Earth orbiting the sun.
127
Grade 6, Unit 6E.1:
Earth and space
Earth and space
6.13.1, 6.13.2, 6.13.3
The Sun –Earth –Moon system
There are nine planets moving around the sun, the Earth is one
of them.
The sun and the nine planets make up the solar system.
The Sun:
The sun warms the Earth. Without the sun the temperature of
the earth would be several hundred degrees below zero.
If we did not have the sun, nothing would be alive on the
Earth.
The sun is the source of light and heat that living things need.
The sun is a star; stars are made up of gases only.
It is much too hot for solids or liquids to exist there. If
something is hot enough, it will “glow”.
128
Grade 6, Unit 6E.1:
Earth and space
Earth and space
“Star light” is the light given out by very hot gases that make
up the stars.
The sun is the source of our daylight.
The sun is a star; it is a huge ball of fire that may reach
6000°C.
Why do we see the sun more brightly than other stars?
---------------------------------------------------
Solar flare
A flare is defined as a sudden, rapid, and intense variation in
brightness. A solar flare occurs when magnetic energy that has
2T
2T
built up in the solar atmosphere is suddenly released.
2T
2T
129
Grade 6, Unit 6E.1:
Earth and space
Earth and space
The moon:
The moon is Earth's only natural satellite.
2T
2T
U
U
The moon is a cold, dry place whose
surface is filled with craters, rocks and
dust. The moon has no atmosphere. Recent
lunar missions indicate that there might be
some frozen ice at the poles.
2T
2T
If you were standing on the moon, the sky would always appear
dark, even during the daytime. Also, from any spot on the
moon (except on the far side of the moon where you cannot see
the Earth), the Earth would always be in the same place in the
2T
2T
sky. The face of the Earth changes because the Earth
rotates, displaying various continents.
Suppose you were on the moon. What
would Earth look like in the sky?
-----------------------------
130
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Where does the moon’s light come from?
The moon’s light comes from reflected light from the Sun.
The sun is a source of light it will shine the
rays of light on the moon. Since the moon is
like a dull mirror it is illuminated by the light
that comes from the sun.
The moon which is an illuminated object will
then reflect the light to our eyes.
The moon is an illuminated object that reflects the light
that shines from the sun.
During the day time we can’t see the moon
because the light that shines from the sun is
much stronger than the light reflected from
the moon.
The Earth, the Moon and the Sun have a
spherical shape. Out of the Earth, moon and
U
U
sun, the sun is by size the biggest, the Earth
is the next biggest and the moon is the
smallest. The diameter of the Earth is about
U
U
12000 km.
131
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Sun, Earth and Moon system
The average distance from the earth to the sun is
149,597,890 km. This distance was not known until recently
and it is called the astronomical unit. The distances of the
other planets to the sun are usually measured in astronomical
units. The average distance from the earth to the moon
is 149,597,870 km.
Project:
Create a display of photographs of the Sun, the Earth and
the Moon system. In your design
• Make very approximate scale models of the Sun, the
Earth and the Moon.
• Include information about their size, climate, and what
the surface is like etc.
132
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Key Ideas:
• The Sun is a source of light and heat, without the sun
there will be no life.
• Earth sun and moon are spherical objects.
• The Sun is much bigger, and then the Earth, and the
moon is the smallest.
• The Moon orbits the Earth and this cause the phases
of the moon.
Key words:
• Illuminated
object
• Lunar month
• Spherical
• Moon phases
• Lunar month
Do you know that?
The word 'sphere' comes from
the Greek word spherical,
which means ball.
Key questions:
Q1: What would be easier to do on the moon than the Earth?
_______________________________________________
Q2: What would happen if Earth moved closer to the Sun?
_______________________________________________
133
Grade 6, Unit 6E.1:
Earth and space
Earth and space
6.13.7,6.13.8
The movement of the Earth
Day and night:
Notice in the following picture, the part of Earth facing the
sun is lighted. This part of the earth has daytime.
The part of the earth away from the sun that is not lighted
has night time.
The spinning of the Earth on its axis takes 24 hours; as a
result we get day and night.
134
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Seasons
Different parts of our planet get different amounts of sun
light.
The more direct sunlight a place gets the warmer it is.
Sun light strikes the equator straight most of the time, so it’s
hottest there.
The equator is an imaginary line that circles
Earth half way between the two poles.
135
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Scientists learn things by observing the sun; they have figured
out that the sun’s changing path shows something about Earth’s
motion. The earth orbits the sun.
U
U
It takes Earth a year to complete one orbit around the
sun.
Look at the picture below.
Do you notice anything strange about the axis?
It is tilted!
U
U
Having a tilted axis means that Earth is tilted a little
to one side as it orbits the sun.
136
Grade 6, Unit 6E.1:
Earth and space
Earth and space
The tilting of the earth's axis causes one part of the earth to
be closer to the sun.
The part of the earth that is closer has summer.
The tilt of the Earth’s axis and its orbiting around the sun
causes the seasons.
In summer:
Because your part of the Earth (hemisphere) is tilted toward
U
the sun, the sun appears highest in the sky.
In summer, the sun’s path is the longest.
Because it is a long pathway, there are more day light
137
Grade 6, Unit 6E.1:
Earth and space
Earth and space
In winter:
U
During winter, your part of the earth (hemisphere) is far from
the sun, the sun appears lower in the sky, this results in the
day light hours becoming less in winter.
U
U
U
U
U
U
In winter the sun’s path way is shorter because the sun is
lower in the sky, there are less daylight hours.
Ancient people used their observations on the sun, earth and
moon to know the date, they created a system that we call the
calendar.
A Calendar, is a system of measuring time for the needs of
civil life, by dividing time into days, weeks, months, and years.
A day is the average time required for one rotation of
the Earth on its axis.
138
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Calendar divisions are based on the movements of the Earth
and the regular appearances of the Sun and the Moon.
The measurement of a year is based on one revolution
of the Earth around the Sun and is called a solar
year. A solar year contains 365 days, 5 hours.
The number of days required for the Moon to circle the Earth
is 29.5 days. This measurement, called the lunar month,
resulted in a lunar year of 354 days, 11 days shorter than a
solar year.
The earliest calendars based on lunar months eventually failed
to agree with the seasons. A month occasionally had to be
intercalated or added, to reconcile lunar months with the solar
U
U
year.
In modern calendars, however, the number of days in a month
in a solar year is not based on the phases of the Moon. The
length of the months is approximately one-twelfth of a year
(28 to 31 days) and is adjusted to fit the 12 months into a
solar year.
139
Grade 6, Unit 6E.1:
Earth and space
Earth and space
A calendar that makes periodic adjustments of this kind is a
solar calendar.
U
U
Examples of Calendars:
Modern calendar
Six years after the death of the Prophet Muhammad
‫ﺻﻠﻰ ﷲ ﻋﻠﻴﻪ ﻭ ﺳﻠﻢ‬, Islam’s second caliph ‘Umar ‫ﺭﺿﻲ ﷲ ﻋﻨﻪ‬recognized the
necessity of a calendar to govern the affairs of the Muslims. This was
first of all a practical matter. Correspondence with military and civilian
officials in the newly conquered lands had to be dated.
A solar year is not based on the phases of the Moon. The length of the
months is approximately one-twelfth of a year (28 to 31 days) and is
adjusted to fit the 12 months into a solar year.
140
Grade 6, Unit 6E.1:
Earth and space
Earth and space
A solar calendar is a calendar whose dates indicate the position of the
earth on its revolution around the sun.
Project:
Design a calendar of your own depending on the solar years,
and label it with the months that represent the seasons in
Qatar.
Key words:
• Seasons
• Tilted
• Equator
• North pole
• South pole
Do you know that?
The ancient Egyptians were the first
to replace the lunar calendar with a
calendar based on the solar year.
Key Ideas:
▫ Movement of Earth around the sun causes seasons and it
takes the earth a year to orbit the sun.
▫ The sun is higher in the sky during summer.
▫ How hot or cold a place is depends on the angle of sun
light.
141
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Key questions:
1. Why is it warmer in the equator than it is in the North
Pole and South Pole? ------------------------------2. How does the tilt of Earth’s axis help cause the
seasons?
-------------------------------------------.
3- a. Suppose you are planning a trip to the South Pole.
What month would you choose to visit there? Explain ---------------------------------------------------.
3- b. Give reasons for your choice: - ---------------------------------------------------------------.
4. The diagram shows the Earth in four positions during its
orbit around the Sun.
a. Which position is summer in Qatar?
Draw an arrow to the position.
Explain why it is hotter during the day
in summer than in winter.
-------------------------------------------------------------------------------------------------------------------------------------------------
142
Grade 6, Unit 6E.1:
Earth and space
Earth and space
6.13.4,6.13.6
The phases of the Moon and eclipses
Phases of the moon
The sun earth and moon are in orbit, the moon orbits the earth
and the earth orbits the sun.
The moon orbits the Earth; it takes about 28 days for one
complete orbit. The 28 days make up the lunar month.
The movement of the moon around the earth causes the phases
of the moon.
People have used the phases of moon to tell the dates.
Muslims use the phases of the moon to know when Ramadan,
Eid and Hajj begin
143
Grade 6, Unit 6E.1:
Earth and space
Earth and space
The orbit of the moon around the Earth takes a lunar month;
as a result we see the different phases of the moon.
The phases of the moon
are shown by these
diagrams.
They show what the moon
would look like when seen
from Earth.
Full Moon
Waning Gibbous Moon
Last Quarter Moon
Waning Crescent Moon
New Moon
Waxing Crescent Moon
First Quarter Moon
Waxing Gibbous Moon
Full Moon (again)
144
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Key questions:
Q1: Draw (4) phases of the moon till day 14 of the lunar
month:
Q2: What is the moon’s phase when it appears closest to the
sun? ___________________________________________
Q5: Circle the right answer for the following:
1. When only a small part of the moon is visible, the moon
may be in its:
a. first-quarter phase
b. waning-crescent phase
c. new moon phase
d. last-quarter phase
.
2. Because the moon rotates once for each revolution around
the Earth,
a. you see some phases more than others.
b. a different side of the moon faces Earth each day.
c. you never see the far side of the moon.
d. the far side of the moon is visible only during the full moon
phase.
145
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Eclipses:
Lunar Eclipse
The moon is an illuminated object that reflects the light that
shines from the sun.
The moon orbits the Earth.
Most of the time, the moon does not move into the Earth’s
shadow, but sometimes it does.
When the moon is in the shadow of the Earth, the sunlight is
blocked by the earth and does not reach the moon.
When the Moon moves into the Earth’s shadow we have a
Lunar Eclipse.
146
Grade 6, Unit 6E.1:
Earth and space
Earth and space
The lunar eclipse happens more often than the solar eclipse
since there is more chance for the moon to be in the shadow of
the earth.
The Earth is much bigger than the moon thus Earth has a
much bigger shadow.
During the lunar eclipse, hardly any sunlight reaches the moon.
The moon becomes very dim.
Comparison between solar eclipse and lunar eclipse:
A lunar eclipse lasts much longer than a solar eclipse. This is
because the Earth’s shadow is very wide where the moon
passes. The moon takes a long time to pass through.
Lunar eclipse can be seen from more areas of the Earth than a
solar eclipse.
From start to finish, a lunar eclipse lasts from three
to four hours and sometimes longer.
During a solar eclipse, the moon’s shadow covers only a small
part of the Earth. A solar eclipse can be seen only in a small
part of the Earth.
147
Grade 6, Unit 6E.1:
Earth and space
Earth and space
During a lunar eclipse, the entire moon is in shadow. It can
be seen from any part of the Earth that is having night at
the time of the eclipse.
Solar Eclipse
How often have you noticed your own shadow following you?
You have seen shadows of trees, buildings, and fences.
You can see a shadow right now!! Just hold your hand close to
the paper. What do you see?
What is a shadow?
A shadow is an area of darkness. It forms when an object
blocks the light.
148
Grade 6, Unit 6E.1:
Earth and space
Earth and space
A shadow is made when
objects block the light.
The Earth and moon are no exceptions. The
Earth and moon block the sun’s light. They
cast huge cone-shaped shadows deep into space.
As the moon orbits the Earth, the Earth sometimes moves
behind the moon .The moon will block the light, a part of the
Earth will be in the moon’s shadow.
For the people at that part of the Earth the moon Eclipses or
blocks out the sun light.
A solar eclipse takes place when the sun, moon and Earth are
in straight or almost straight line with the moon between the
sun and the Earth.
149
Grade 6, Unit 6E.1:
Earth and space
Earth and space
The eclipsed area becomes dark. For a short period of time it
looks like it is night time.
A solar eclipse does not last long – no longer than a few
minutes in any one place.
Comparison between Solar Eclipse and Lunar Eclipse:
U
Solar Eclipse
Lunar Eclipse
The moon shadow covers only
a small part of the Earth.
The moon shadow covers large
part of the Earth.
It takes a short time to
complete.
It takes (3-4) hours or longer
to complete.
Can be seen from limited
areas of Earth.
Can be seen from different
areas of Earth.
150
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Key words:
•
•
•
•
•
•
Eclipse
Orbit
Rotation
Phase
Umbra
Penumbra
Do you know that?
The Earth, lit by the Sun, casts a long,
conical shadow in space. At any point
within that cone the light of the Sun is
wholly obscured. Surrounding this shadow
cone, called the umbra, the area of
partial shadow is called the penumbra.
Key Ideas:
• A Lunar eclipse happens when the moon moves into
the Earth’s shadow.
• Lunar eclipses occur more often than solar eclipses
and last longer.
• This is because the Earth is much bigger than the
moon.
Project: Lunar Eclipses
1. When did the last lunar eclipse happen in Qatar?
----------------2. How long did it take? ------------3. Where else was it visible from earth?
--------------------------------------------3. When will the next one occur? -----------------
151
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Key questions:
Q1: Write true or false:
a. _______ during lunar eclipse, the moon is in the
Earth’s shadow.
b. _______The moon reflects the sun’s light.
c. _______ The phases of the moon always take the
same number of days.
d. _______ Solar eclipses must occur during New
Moon phase.
Q2: Find the answer for the following questions:
1. A lunar eclipse takes place only during one moon
phase. Which phase is it?
______________________________________
2. The lunar eclipse lasts much longer than a solar
eclipse?
_________________________________________
Q3: Which of the following describes an eclipse of the
Moon?
A. The Moon passes between the Earth and the Sun.
B. The Sun is not illuminating the side of the Moon
facing the Earth.
C. The shadow of the Moon passes across the surface
of the Earth.
D. The shadow of the Earth passes across the surface
of the Moon
152
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Key question:
Figure (A) shows a solar Eclipse. Study it and answer
the questions:
Q1: Match the letter on the picture with the words:
-----1. Sun
-----2.Earth
-----3. Moon
-----4. Moons orbit
-----5. Total eclipse
---6. Partial eclipse
The shadow has a dark middle part, and a lighter outer
part.
5. What do we call the darker middle part? ---------6. What do we call the lighter outer part? ----------Q2: Draw diagram on your note book that represents a
solar eclipse.
153
Grade 6, Unit 6E.1:
Earth and space
Earth and space
6.13.5
T ides
Have you ever spent a day at the beach?
If you have, then you know that the water of the ocean does
not stay at one level.
At certain times of the day the water is higher than at other
times.
The water level rises and falls at regular time periods.
Tides are the regular rise and fall of ocean’s level.
High Tide
Low Tide
There are two major types of tides:
1. High tides
2. Low tides
154
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Tides do not change suddenly. High tide moves in slowly, then
after the water reaches its highest point, it moves out slowly.
A low tide is followed by a high tide, which is followed by a low
tide, which is followed by another high tide.
Most sea shores have four tides every day, two high tides and
two low tides.
A change of tide takes about 6 hours and 12 minutes.
What causes tides?
The sun, earth and moon are in orbit.
Tides are caused by the pull of gravity by both the moon and
the sun on the earth.
The moon is more important in causing tides because it is closer
to the Earth.
The moon pulls on the Earth with greater force than the sun.
The moon pulls upon the Earth’s land and water. The pull has
hardly any effect upon the land. The rock, part of earth does
not move easily. But water is different, water moves very
easily, it flows.
155
Grade 6, Unit 6E.1:
Earth and space
Earth and space
The pull bulges the water on the part of the Earth that is
facing the moon. This part of the Earth has high tide. There is
a high tide on the opposite side of the Earth the side facing
away from the moon as well. The Earth is always rotating. As
it turns different parts face the moon, this causes the tides to
keep changing.
The sun also has an effect on tides. Its effect is less than the
moon. This is because the sun is so far away. Its pull upon the
Earth is very weak.
156
Grade 6, Unit 6E.1:
Earth and space
Earth and space
When the moon and the sun are pulling in the same direction we
get higher tides.
Key words
• Tides
• Pull of Gravity
• Neap tide
• Spring tide
Project:
Go to the seashore and mark the
level of the water. On the next day
at the same time, go and observe the
level of the water. Record your
observations. Do this for several
days if you can.
Key ideas:
• Tides are the regular fall and rise of ocean’s water.
• The average change of tides takes 6 hours and 12 minutes
but has different lengths in different places.
• Tides are caused by the pull of gravity by both moon and
sun. The highest tides occur at Full Moon and New Moon.
157
Grade 6, Unit 6E.1:
Earth and space
Earth and space
Key questions:
1. Which one is more important in producing tides? The
moon or sun? ______________________
Why? ____________________________________
2. Look at the following diagram, and answer the questions
below:
1. Which side of the Earth is facing the moon? ________
2. Which sides of the Earth are having high tide? _____
3. Which sides of the Earth are having low tides? _____
3. If gravity is always pulling towards the moon, what
causes the bulge on the opposite side of the earth?
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
158
Grade 6, Unit 6E.1:
Earth and space