The Water Cycle - Evaporation

Water on the ground isn’t just in oceans, lakes, and rivers. Water is in almost everything - in fact, around 70 per cent of the adult human body is water. 

This means that it isn’t just the ocean that contributes to this stage of the water cycle, it’s everything. The ocean might be the biggest contributor, covering 70 per cent of the world’s surface, but water is becoming vapour everywhere.

Evaporation means turning from liquid into gas - or vapour. This is what happens when the sun heats up liquid water. Research has observed that almost 90 percent of water in the atmosphere comes from the ocean and other bodies of water such as seas, rivers, and lakes. 

What about the other 10 per cent? Almost all of this comes from trees. 

Trees go through a process that is similar to our own breathing, and just like we breathe out water vapour, trees do the same. We call this process transpiration. 

Make it happen

You can see the results of transpiration by tying a clear plastic bag around the leaves of a plant near your house. Leave it for a while and you’ll find water inside the bag. This is all from transpiration of the water in the leaves.
Don’t forget to take the bag back off.
Transpiration
Water cycle

 

Did you know? It is also possible for water to turn straight from solid ice into a gas? We see this a lot on glaciers, and call this process sublimation.

Anatomy of a Glacier

Evaporation is a great way to purify water. When the sun evaporates ocean water, the salt doesn't travel with it, which means it's fresh when that water returns to the earth via precipitation.

 

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