STUDENT SPACE · TOPIC 2
States and changes of state
Describe the three states and use melting and boiling points to predict a state.
The essentials
- Solids have a fixed shape and volume. Liquids have a fixed volume but take the shape of their container. Gases fill their container.
- Melting and boiling require energy; freezing and condensation release energy.
- Evaporation occurs at the surface below the boiling point. Boiling occurs throughout a liquid at its boiling point.
Key vocabulary
| English | Chinese |
|---|---|
| melting | 熔化 |
| freezing | 凝固 |
| boiling | 沸腾 |
| evaporation | 蒸发 |
| condensation | 凝结 |
| sublimation | 升华 |
Quick practice
Water disappears from a wet floor at room temperature. Is this boiling or evaporation? Give one reason.
Need a hint?
Think about where the change occurs and whether the water has reached its boiling point.
Check your reasoning after trying
Evaporation: water escapes from the liquid surface below its boiling point.
For more written practice, use Lesson 2 in your worksheet. Your teacher will discuss those answers in class.
Try it: States of Matter
Compare solid, liquid and gas. Describe the spacing and movement of particles in each.
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