What are materials made of?
              1. Solids, liquids and gases
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Solids, liquids and gases on other planets
Ice, water and steam
Picture 1.12 What happens to water at different temperatures? Notice that, at room temperature, it is a liquid.
We can group the materials around us as solids, liquids or gases. The materials around us are at room temperature. In the United Kingdom this is usually about 15 °C. Water is a liquid at room temperature because 15°C is above its freezing point of 0 °C, but below its boiling point of 100 °C.
Sulphur is a yellow substance produced by volcanoes. It has a melting point of 114 °C, which is well above room temperature, so we classify sulphur as a solid.

Sulphur dioxide is another substance that is produced by volcanoes. It has a boiling point of -10 °C, which is below room temperature. So we classify sulphur dioxide as a gas.

Picture 1.13 Sulphur is a yellow solid. It can be granules, a powder or a solid lump. Photo of different types of sulphur
Venus and Mars cartoon
Picture 1.14 It's hot on Venus and cold on Mars!

And on Mars or Venus?
If you were to visit one of our neighbouring planets, Venus or Mars, room temperature would be very different from what it is here on Earth. Venus is nearer the Sun than the Earth and has a surface temperature of about 477 °C. Mars is further away from the Sun than the Earth and has a surface temperature of -47 °C.
Question 7
The melting points and boiling points of water, sulphur and sulphur dioxide are given in the table. Use the information to decide whether the materials would be solids, liquids or gases on the surface of Venus and Mars.
Material Melting point
/ °C
Boiling point
/ °C
State on Mars
– 47 °C
State on Venus
477 °C
Water 0 100
Sulphur 114 444
Sulphur dioxide -73 -10
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