Transcription
About 71% of Earth's surface is covered with water. Most of this water is in the oceans. Some is in rivers, streams, lakes, glaciers, and even plants and animals. Without water, living things could not survive on Earth.
Earth's water can move from place to place through a process called the water cycle. In this process, water rises up into the air to form clouds, then it falls back to Earth's surface again to start the cycle.
Water must change from a liquid into a gas so that it can rise up into the sky. This is called evaporation or transpiration. Like most processes on Earth, the water cycle begins with heat from the Sun. The sun's heat warms up the water on Earth's surface. When this happens, the water changes from a liquid into a gas called water vapor.
You can watch this same process when you boil water on a stove. When the water heats up, you begin to see steam rising up. If you continued heating the water, eventually there would be none left in the pot. It would all rise into the air as steam. Steam is water vapor.
Evaporation happens when water collected in rivers, lakes, streams, ponds, oceans, and even puddles is heated into water vapor. The vapor rises into the air to form clouds. Evaporation of bodies of water is where most of the water vapor in the atmosphere comes from.
Transpiration is similar to evaporation, but the water comes from the leaves of plants. Plants absorb water through their roots. However, they only use a little bit of this water to grow and live. The rest of the unused water makes its way to the leaves. There, it is heated by the Sun and becomes water vapor. The water vapor rises into the air to later form clouds.
Evaporation and transpiration are both ways that water makes its way from Earth's surface into the atmosphere. This water vapor will form clouds. Eventually, the water will fall back to Earth. This water will run into bodies of water and be reabsorbed by plants. In this way, we are constantly recycling Earth's precious water supply. Without it, nothing could survive.
This video was created by La Fontaine of Knowledge. Click the link in the description for lesson materials that go along with the video and subscribe to my channel for more videos like this.