- Education and Science
Learn About the Water Cycle for Kids
Two thirds of the Earth's surface is covered in water. That's a lot of water. Yet we can't drink most of it. We need fresh water to drink and bathe. Most water on Earth, like that found in the oceans, is salt water. Only a small amount of water is usable by us. So, how come fresh water doesn't run out even though we use so much of it?
Water doesn't run out because it's constantly renewed by the water cycle. A cycle is something that happens over and over again. Water is continuously being evaporated into the sky and sent back to the ground as precipitation.
These are the steps in the water cycle:
Water Cycle Song
Step 1: Evaporation
Water evaporates from the Earth's surface. This means that it turns into a gas called water vapor and rises into the air. Much of this evaporated water comes from the oceans. It also comes from lakes, rivers, ponds, the soil and even plants.
You might be surprised to see plants on the list of sources of evaporation. But they release water vapor into the air through a process called transpiration. In this process, moisture is carried through plants to small pores on the bottom of the leaves. It changes to water vapor and is released into the atmosphere. So, transpiration is the evaporation of water from a plant's leaves.
Water Cycle Animation
Step 2: Condensation
Condensation is the opposite of evaporation. Water vapor condenses when it turns back into water. Water vapor in the air cools and condenses into tiny droplets. Have you ever seen steam from a shower turn to water droplets on a mirror? The steam condenses or turns into water droplets when it hits the cold mirror. Water vapor in the air condenses and forms clouds.
Step 3: Precipitation
Water from the clouds falls back to Earth as precipitation. Precipitation includes rain, snow, hail and sleet.
When rain falls, some of the water seeps into the ground. This is called groundwater. When it hits rocky layers, it can't go down any further, so it starts to build up and fill all available space. The top is called the water table. Whenever the water table reaches above the surface a lake, pond or stream forms. This usually happens when water fills low lying areas.
Streams flow downhill, often meeting other streams. They become larger until they turn into rivers. Rivers eventually reach the ocean. All these bodies of water become sources of evaporation in the water cycle.