The Water Cycle

1. The Water Cycle

2. Activity • What happens to make rain fall from the sky? • I will now demonstrate a model of what happens when it rains. • Measure 250ml of water and pour it into the kettle or pot. • This is the water in a lake, river and the ground.

3. What do you think happens to water in these places as the Sun shines on Earth. • The warmth from the Sun heats water. • Heat water in the pot or kettle to simulate this process. • What do you observe?

4. What is happening to the heated water? • Evaporation is when water changes from a liquid to a gas when it is heated. • The water vapour rises because it is lighter than liquid water.

5. This is what happens to water in rivers and lakes when it is heated by the Sun. • The water evaporates and rises into the sky. • What do you think the temperature is like far up in the sky? • Is it very hot or very cold?

6. Temperature above land is cold since the heat from the Sun is absorbed and reflected off the land, warming the areas closest to the ground. • Place the pie plate of ice cubes above the evaporating water.

7. Observe the bottom of the pie plate. • What do you notice on the bottom of the pie plate? • Where are these water droplets coming from? • What is happening to the droplets as they get bigger?

8. The water vapour is cooled by ice cubes in the plate, it condenses into liquid form, or water droplets. • When these droplets run into one another, they join together and get bigger and heavier, eventually falling from the pie plate. • This is what happens to water vapour in the sky.

9. The water vapour cools, condenses, and forms droplets that fall to the ground as rain. • This whole process is called the water cycle. • Picture on 4.3.1 • 4.3.2 Activity sheet-Label the water cycle.