A CIESE Collaborative Project

The Water Cycle


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What is the water cycle?

In nature everything happens in cycles, the water cycle is just one of many. Lakes, oceans, rivers, streams and reservoirs lose water by means of evaporation. Water is released into the atmosphere by plants, called transpiration ( water is released from plants through little holes on the under-leaf called stoma or right from the leaf's skin, the cuticle). We are also a part of the water cycle. For example, when we water our lawns evaporation takes place releasing moisture into the atmosphere. Simple things like hanging clothes out to dry, splashing water when we go for a swim, or using water pistols contributes to evaporation.

Once water vapor is in the atmosphere it can condense to form clouds or simply stay in the air. When it is about to rain it can be very humid. Humidity is how much water the air around you can hold.

As water vapor accumulates in clouds the tendency to form water droplets is evident. On a humid and cloudy day the clouds are carrying a lot of water. Water droplets form and then fall back to earth as rain or some other form of precipitation. Forms of precipitation include snow, sleet, hail.....can you think of any more?

When it rains the ground absorbs a lot of the water which seeps into lower layers. This water is called ground water and can be used by plants or people who dig wells that tap into ground water. The rain also reaches oceans, rivers, driveways, and lawns and once again evaporation occurs and the water cycle continues. Check out the picture below which is a diagram of the water cycle.