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KS3 Physics
7L The Solar System and Beyond
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7L The Solar System and Beyond
Contents
Days, years and seasons
The Moon
The Solar System
Summary activities
Satellites and probes
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How long is one day?
24 hours
How long is one year?
365¼ days
The Earth spins on its axis, which is tilted at an angle of 23.5°, and also orbits the Sun.
This causes day and night and the seasons.
Day and night
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sun
ligh
t
It take the Earth 24 hours to complete one rotation about its axis.
Day and night
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What time is it?
It is 04:00 in London. What time is it in other parts of the Earth?
Place GMT Time
Casablanca +1
Pretoria +2
Antanarivo +3
Philippines +8
05:00
06:00
07:00
12:00
Casablanca
Philippines
Antanarivo
Pretoria
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The seasons
summer in the UK
winter in the UK
autumn in the UK
spring in the UK
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7L The Solar System and Beyond
Contents
Days, years and seasons
The Moon
The Solar System
Summary activities
Satellites and probes
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The Sun and the Moon look about the same size from Earth, but they are not.
The Sun is about 400 times wider than the Moon but is 400 times further away!
The Moon takes just over 27 days to orbit the Earth.
sun
ligh
t
The Moon
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1. The Moon does not produce its own light - how can we see it?
2. How long does it take the Moon to orbit the Earth?
3. Why do we always see the same side of the Moon?
4. Why do we only see a full Moon once a month?
5. What is a new Moon?
6. What force keeps the Moon in orbit around the Earth?
7. Why is there very little atmosphere on the Moon?
8. How does the Moon cause tides?
Questions about the Moon
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A solar eclipse happens when the Moon passes between the Sun and the Earth. This casts a shadow over the Earth.
The last solar eclipse over the UK was on 11th August 1999. Solar eclipses do not occur very often.
A lunar eclipse happens when the Earth passes between the Sun and the Moon. This casts a shadow over the Moon.
Lunar eclipses happen in most years.
Eclipses
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Where must the Moon be for a solar eclipse to take place?During a solar eclipse the Moon moves directly between the Sun and the Earth.
What happens during a solar eclipse?
During a solar eclipse the Moon blocks the Sun’s rays from reaching part of the Earth.
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Always use eclipse viewers, NEVER look directly at the Sun.
The Earth
Viewing a solar eclipse
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Where must the Moon be for a lunar eclipse to take place?During a lunar eclipse the Moon is on the opposite side of the Earth to the Sun.
What happens during a lunar eclipse?
During a lunar eclipse the Earth blocks the Sun’s light from reaching the Moon.
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1. Why do eclipses only last a few minutes?
2. Why do you think ancient people were frightened of eclipses?
3. What causes an eclipse of the Sun (a solar eclipse)?
4. What causes an eclipse of the Moon (a lunar eclipse)?
5. What would a lunar eclipse look like if you were an astronaut standing on the Moon?
6. Draw simple ray diagrams of a:
a) solar eclipse
b) lunar eclipse
Questions about eclipses
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7L The Solar System and Beyond
Contents
Days, years and seasons
The Moon
The Solar System
Summary activities
Satellites and probes
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Using the information about the Solar System, plot a graph of ‘surface temperature’ [y] against ‘distance from the Sun’ [x]:
-300
-200
-100
0
100
200
300
400
500
0 1000 2000 3000 4000 5000 6000 7000
What happens to the surface temperature of planets as they get further away from the Sun?
Predict the surface temperature of a planet that is 7000 km away from the Sun.
Temperature in the Solar Systemsu
rfac
e te
mp
erat
ure
(ºC
)
distance from the Sun (millions Km)
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2. Using books or any other sources of information find out five facts about that planet.
3. Design a postcard from that planet. You need to draw a front to the postcard that suits your planet.
4. Write a postcard to someone on Earth as if you are visiting the planet you have chosen. You must use your five facts in your postcard.
Planet postcards
1. Choose a planet that you would like to know more about. You cannot choose Earth.
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1. Choose a planet that you would like to know more about.
2. Find out about that planet using books and other sources of information.
3. Design a travel brochure to encourage people to come and visit the planet.
You could tell people:- how they can get there and how long it will take;- the climate of the planet;- where they will stay;- what sights they can see on the planet.
Planet travel guides
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7L The Solar System and Beyond
Contents
Days, years and seasons
The Moon
The Solar System
Summary activities
Satellites and probes
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For thousands of years, humans have been fascinated by the night sky and what lays beyond it.
Beyond the Solar System
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Science fiction writers first suggested the idea that artificial satellites could be put into orbit around the Earth.
This only became reality in 1957 when the Soviet Union placed Sputnik I and Sputnik II into orbit – Sputnik II carried a live dog called Laika!
Today, artificial satellites are frequently launched by space shuttles and unmanned rockets.
Satellites – science fiction to science fact
Artificial satellites have many uses including communications, satellite TV, weather forecasting and navigation.
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Astronomical satellites, such as the Hubble Space Telescope (HST), are large telescopes placed in a high orbit far away from the effects of the Earth’s atmosphere.
These satellites can ‘see’ much further into space and give us images of stars and galaxies many light years away, like this cartwheel galaxy.
Using satellites to view space
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Our search for answers and clues to the origin of the Solar System and the possibility of life elsewhere led to the development of unmanned space probes.
For years, science fiction had brought us stories of Martians - but could they really exist or have existed?
On 4th December 1996, NASA launched the ‘Pathfinder’ Discovery Mission to Mars. It cost $150 million and took 7 months to reach Mars.
Exploring space – mission to Mars
When it had landed, the ‘Sojourner Rover’ buggy tested Mars’ atmosphere, surface and weather, amongst other things.
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The Sojourner Rover
Mission to Mars – the Sojourner Rover
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The tests carried out by the Rover showed that Mars is much more like the Earth than was expected.
Was Mars like the Earth until something catastrophic happened?
Mission to Mars – tests on Mars
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Why did the volcanoes stop?
Did the gases they gave out kill any Martian life?
The tests also showed that the crust of Mars is very similar to continental crust on Earth and that volcanoes had played a part in Mars’ formation.
Mission to Mars – volcanoes on Mars
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Did it rain on Mars?
How much water was there on Mars?
Was there life in the water?
The surface of Mars has undergone intense erosion by massive floods and by strong winds.
Mission to Mars – erosion on Mars
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1. Give two uses of artificial satellites.
2. Why can the Hubble Space Telescope ‘see’ much further into space and produce much clearer images than telescopes on Earth?
3. Why didn’t NASA send astronauts to Mars instead of spending millions of dollars on the ‘Pathfinder’ Discovery Mission?
4. Give two reasons why there is unlikely to be life on Mars.
Questions about satellites and probes
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Many people believe that we are not the only intelligent life in the Universe.
The challenge for scientists is to find evidence of other life.
Is there life out there?
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7L The Solar System and Beyond
Contents
Days, years and seasons
The Moon
The Solar System
Summary activities
Satellites and probes
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Glossary
axis – The line that the Earth rotates about, which is tilted at an angle of 23.5°.
lunar eclipse – The blocking of the Moon’s light, when the Earth passes between the Sun and the Moon.
luminous – An object that gives out light.orbit – The path of a planet around the Sun, or the path of
a satellite around a planet.satellite – Any object that orbits another object.seasons – The different periods of a year caused by the
tilt of Earth’s axis.solar system – The Sun and the collection of planets
and other objects orbiting around it.solar eclipse – The blocking of the Sun’s light, when the
Moon passes between the Earth and the Sun.