Science primary 4: Changing State of Water
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Water exists in three states - solid, liquid, and gas - and can change between these states when it gains or loses heat. It freezes into ice at 0°C when it loses heat, melts back into liquid water when it gains heat above 0°C. Water boils into steam at 100°C when sufficient heat is added, and condenses back to a liquid when steam cools below 100°C losing heat. The rate of evaporation depends on factors like wind, temperature difference, and surface area.
Science primary 4: Changing State of Water
- 1. Changing States of Water Water exists in three states Water can changes its state when it becomes colder (loses heat) or hotter (gains heat)
- 2. When water loses heat or gains heat When water is cooled to 0 °C, it changes to ice Water changes from liquid to solid state Freezing loses heat The freezing point of pure water is 0°C
- 3. When ice cube at 0 °C gains heat, it changes to the liquid state Water changes from solid to liquid state Melting gains heat
- 5. When we heat water to a temperature 100 °C, it changes the liquid water to steam Water changes from liquid to gaseous state at 100 °C Boiling The boiling point of pure water is 100°C
- 6. When we heat water at temperature below its boiling point, the liquid water changes into water vapour Water changes from liquid to gaseous state at temperature below 100 °C Evaporation gains heat
- 7. When water vapour and steam are cooled, it condense into liquid water Water changes from gaseous to liquid state Condensation loses heat
- 8. How quickly or slowly evaporation takes place is known as the rate of evaporation The rate of evaporation depends of: - wind - temperature difference - surface area