Unit 3: States of matter

Evaporation and condensation, the water cycle, boiling and melting, and the story of the temperature scale.

• 3.1 Evaporation – Where does a puddle go when it dries up?
• 3.2 Why evaporation is useful – Dry fish, salt and cool water from a clay pot.
• 3.3 Investigating evaporation – What makes water evaporate faster?
• 3.4 Investigating evaporation from a solution – Evaporate the water and the dissolved solid is left behind.
• 3.5 Condensation – Why do drops appear on a cold glass?
• 3.6 The water cycle – The same water goes round and round, for ever.
• 3.7 Boiling – Bubbles, steam and 100 °C.
• 3.8 Melting – Ice melts at 0 °C – and stays at 0 °C until it has all melted.
• 3.9 Who invented the temperature scale? – Galileo, Fahrenheit and Celsius – the story of measuring hot and cold.