Year 7 Science · Unit 4 · Lesson 17
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Learning Goals
Sort the space objects
Read each clue, then write whether it describes a moon, an asteroid or a comet.
| Clue | Moon, asteroid or comet? |
|---|---|
| It is icy and grows a glowing tail when it nears the Sun. | |
| It is a natural satellite that orbits a planet. | |
| It is a rocky leftover, mostly found in the belt between Mars and Jupiter. | |
| Titan is the largest one of these belonging to Saturn. |
Real-world context
A comet sweeps in from the cold outer edge of the Solar System. As it races towards the Sun, the Sun's heat warms its ice and turns it into gas and dust, which stream off the comet and form a long glowing tail. Sunlight and the stream of particles flowing out from the Sun push this gas and dust away. The comet loops around the Sun and then heads back out into deep space.
(a) On the way towards the Sun, in which direction does the comet's tail point? On the way back out, in which direction does the tail point? Explain why.
(b) A friend draws a comet with its tail trailing behind it like smoke behind a car. Explain what is wrong with the drawing and how it should look instead.
(c) A space probe travels from Mars towards Jupiter and passes through the asteroid belt without hitting anything. Even though there are millions of asteroids, explain why the probe can pass through safely.
1. A large iron meteorite strikes a flat desert plain at very high speed. Describe what happens to the ground, and name the feature that is left behind. Use Wolfe Creek Crater (Kandimalal) in your answer.
2. Most meteors burn up before they reach the ground, so very few become meteorites. Explain why we still see many "shooting stars" but rarely find a meteorite.
Wrap Up
In one sentence, what was the main idea of this lesson?