What is the water cycle?
The water on our planet is constantly moving between the hydrosphere, the atmosphere and the geosphere. This movement is called the water cycle. As the water moves, it changes state (liquid, gas or solid) because its temperature goes up or down. There are four processes:
- 1☀️ Evaporation
The Sun heats the water in oceans, rivers and lakes, and some of it turns into water vapour and goes up.
- 2☁️ Condensation
The water vapour rises, cools down and condenses into tiny droplets that form clouds.
- 3🌧️ Precipitation
The droplets in the clouds get heavy and fall as rain, snow, hail or sleet.
- 4🏞️ Collection
The water collects in rivers, lakes, oceans and aquifers. Then the cycle starts again!
Pour water and a few drops of food dye into a large bowl. Put a small empty container in the middle. Cover the bowl with transparent film and put a small heavy object on the film, just above the container. Leave it in a sunny place for two hours. What happens to the film? Drops of water appear (condensation) and drip into the small container (precipitation and collection). The water in the container is clear, because the dye does not evaporate!
To ask about experiences we use the present perfect: Have you ever seen a waterfall?· Have you ever swum in the sea? · Have you ever drunk water from a well? Answer: Yes, I have. / No, I haven't.