© Oxford University Press 2011 IP1.5.3 Evaporation and condensation Evaporation and condensation

© Oxford University Press 2011 IP1.5.3 Evaporation and condensation Look at these two saucepans. How will evaporation affect how quickly the contents of the saucepans will heat up?

© Oxford University Press 2011 IP1.5.3 Evaporation and condensation The particles with the most thermal energy will evaporate from the saucepan without a lid.

© Oxford University Press 2011 IP1.5.3 Evaporation and condensation The saucepan with the lid stops these particles escaping and so its contents will heat up quickest.

© Oxford University Press 2011 IP1.5.3 Evaporation and condensation This is why takeaway cups have lids. They are also made of a material which is a good thermal insulator. Both these things help to keep your drink warm and stop your hand burning when you hold it!

© Oxford University Press 2011 IP1.5.3 Evaporation and condensation Look at the window behind this cooker. Can you explain why the glass is covered with condensation?

© Oxford University Press 2011 IP1.5.3 Evaporation and condensation The gas which has evaporated from the saucepan, without the lid, touches the cool surface of the glass. The gas particles lose thermal energy and condense to form a liquid.