The Sun and gravity keep water moving
Water is always on the move. The water cycle moves water between reservoirs: oceans, lakes, rivers, ice, soil, living things and the air. It follows five steps. Evaporation turns liquid water into vapour. Condensation turns the vapour into tiny droplets, which form clouds. Precipitation is rain, snow or hail falling from the clouds. Collection happens when the water gathers in the sea, lakes, rivers and ground. Runoff is water flowing over the land to join rivers and the sea. Two things drive this: energy from the Sun lifts the water into the air, and gravity pulls the rain down and makes water flow downhill. The cycle never ends and no water is lost.
| Step | What happens | Driven by |
|---|---|---|
| evaporation | liquid becomes vapour | the Sun |
| condensation | vapour becomes droplets | cooling air |
| precipitation | rain or snow falls | gravity |
| runoff | water flows over land | gravity |
Cycle cards. With a grown-up, write the five steps on cards and put them in order in a circle with arrows. Add a card for each reservoir. Then tell a family member the journey of a drop from the sea to a river. Do not draw a landscape: cards and arrows are enough.