Starter quiz
- What happens when Earth orbits the Sun?
- Earth spins on its axis so it faces the Sun once each day
- Earth moves in a circular path around the Sun once each year ✓
- the Sun moves in a circular path around Earth once each day
- the Sun moves in a circular path around Earth once each year
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- Which of the following objects orbit Earth?
- the Moon ✓
- the Sun
- stars
- the International Space Station ✓
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- Which of the following objects orbit only the Sun?
- asteroids ✓
- dwarf planets ✓
- stars
- the moons of Jupiter
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- Starting with the planet with the fewest moons, sort the following planets into increasing order of number of moons.
- 1⇔Mercury
- 2⇔Earth
- 3⇔Mars
- 4⇔Jupiter
- How many artificial satellites orbit Earth?
- fewer than ten
- about a hundred
- about a thousand
- more than ten thousand ✓
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- Starting with the planet that takes the shortest amount of time, sort the following planets into increasing order of how long they take to orbit the Sun.
- 1⇔Mercury
- 2⇔Venus
- 3⇔Earth
- 4⇔Mars
- 5⇔Jupiter
- 6⇔Saturn
Exit quiz
- Titan is a large moon of Saturn. Which of the following statements most accurately describes Titan?
- Titan is a natural satellite of the Sun.
- Titan is a natural satellite of Saturn. ✓
- Titan is an artificial satellite of Saturn.
- Titan is a planet in orbit around Saturn.
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- Which of the following types of satellites are often found in low Earth orbits?
- the Moon
- communication satellites
- observation satellites ✓
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- How does a geostationary satellite move around Earth?
- it remains still as Earth spins beneath it
- it orbits once each day ✓
- it orbits several times each day
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- Why are communication satellites usually placed in a circular orbit of 35 785 km above the Equator?
- so they don't collide with the Moon
- so they remain above one point on Earth's surface ✓
- so they move across the whole of Earth each day
- so they can send signals directly to every country on Earth
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- What force acts on a satellite in geostationary orbit?
- frictional force
- gravitational force ✓
- thrust
- buoyancy
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- Starting with the satellite that has the fastest orbit, sort the following satellites of Earth into increasing order of how long they take to orbit Earth.
- 1⇔a weather satellite in a low Earth orbit
- 2⇔a communications satellite in a geostationary orbit
- 3⇔the Moon
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Artificial satellites orbit Earth because of the gravitational attraction between them.
- The speed of a satellite along its orbit around Earth is constant.
- The velocity of a satellite along its orbit around Earth constantly changes as it changes direction.
- The gravitational force on a satellite makes it accelerate and change direction, but not speed.
Common misconception
Motion is always in the direction of the force acting on an object.
Provide pupils with opportunity to experience a radial force changing the direction of a small object in order to make it move in a circular path.
Keywords
Satellite - an object which orbits a planet; satellites can be natural (moons) or artificial
Polar orbit - an orbit in which the satellite passes over the poles of a planet
Geostationary orbit - an orbit in which the satellite is stationary in the sky as it orbits in the same time as the planet, directly above its equator
Orbital path - the path a satellite takes around the planet it orbits
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