Science at key stages 1 and 2    (Year 5)

• Remind children what happens to puddles in the playground when it stops raining and to wet washing when it is put out to dry. If it seems appropriate, make wet hand prints on a surface eg blackboard and watch them disappear. Show children what happens to water in a saucepan as it is heated, noting both water level and the connection between evaporation and heating and use this as a stimulus to discuss ideas about evaporation and where they encounter evaporation.

• Demonstrate using eg nail varnish, correction fluid, that other liquids evaporate. Ask children to explain why they can smell eg perfume, aftershave, natural gas from a distance.

• Talk with children about how they could investigate a question related to evaporation eg What makes a difference to how quickly washing dries? What affects how fast a puddle dries up and how can we turn it into a form that could be tested? Discuss possible relevant factors eg temperature, wind, amount (volume) of water surface area and how these might be investigated. Help children to plan a fair test to investigate their question eg keeping volume of water and surface area the same while temperature is changed and to decide what evidence to collect eg depth, volume of water in containers kept at different temperatures over a period of days.

• Discuss results with the children and help them to present them as a graph. Compare results from different investigations and ask children what the results show about the factors affecting evaporation, to make generalisations and to try to explain eg the warmer the place, the faster it evaporates; washing dries better on a windy day, I know this because the water evaporated faster by the open window than in other places.

• Show pictures of appliances eg hairdryers, tumble dryers, rotary clothes line and ask children to explain how these help to make things 'dry' more quickly. Record explanations in writing eg in an advertisement for a particular sort of appliance.

• Demonstrate an example of condensation eg steam from a kettle hitting a cold surface and discuss with children what happens to water vapour when it cools down. Discuss with children where in their homes they see water collecting on surfaces eg in the kitchen, bathroom. Introduce the words 'condense' and 'condensation'. Demonstrate what happens when ice cubes are placed in the centre of cling film covering a container of hot/warm water. Ask children to feel the cling film to see how warm it is in different places and to observe the size of the droplets. Ask children to illustrate in diagrams and annotate to explain what happens.

• Show children examples of condensation where there is no obvious source of water vapour eg breathing on a cold window pane, droplets of water collecting on a metal glass containing mixture of ice and water, droplets of water collecting on a can of soft drink from the freezer. Ask children where they think the water came from and to record in a drawing with annotation.

• Show children a chart or graph of the temperature of a container of water as it is being heated eg temperature rising 5 degrees every minute from 20°C to 45°C and ask them to predict what the next five readings will be. Then show them similar results from 90°C and ask them to make similar predictions. Using an IT sensor (or a suitable thermometer), carry out the experiment and compare results with predictions or use results already obtained. Talk with the children about what the results show about boiling.

• Use an IT sensor to take the temperature of a mixture of ice and water at five minute intervals over a period of two or three hours. Discuss what the data shows about the melting temperatures of ice and the temperature of the room. Ask children to predict what the data would show if the room was ten degrees hotter.

• Review work on changing state by presenting children with pictures or descriptions of simple situations eg breathing on a mirror, a picture of a kettle boiling, clouds forming, wax running down the side of a lighted candle, a wet hand print on a suitable surface eg blackboard, molten lava from a volcano solidifying, leaving an ice cube in a warm room and asking them to link the situation to the process involved. Re-introduce the terms 'state' and 'changes of state'.

• Ask children a question about our water eg Where does our bath water come from? Visit a water works or use secondary sources eg video, CD-ROM, reference books to show where our water supply comes from. Help children to see the relationship to earlier work on evaporation and condensation, and to work on rocks and soils, and to use what they know to build up the water cycle from first principles.