Today's water is left over from the time when the earth was created. The earth makes a little bit of new water all the time but she recycles water best. So, you could say the water cycle is the Earth's way of recycling water.
When the earth warms up, the water evaporates. This is kind of like boiling water on your stove. The steam coming from the pot is vapor or gas.
The Earth works the same way. The sun heats up the lakes, streams and oceans. The water gets warm and turns into vapor. The vapors rise into the sky, also called the atmosphere. There the vapor turns into tiny drops. Those drops stick together and form clouds. When the clouds become too heavy they have to let the drops go and they come down and we see it as rain, snow or ice, this is also called precipitation.
To see this cycle in action click here.
When precipitation falls back into the ocean, the sun starts warming it up again, turns into steam and makes clouds. If the rain falls on dirt or streets then it has to find its way to a river or other place where the dirt can suck up the water, much like a sponge. Eventually all the water will make its way back into the air by evaporation.
About 3 trillion tons (2.7 metric tons) of ocean water evaporate every day! That is enough water to fill Chase Field, where the Diamondbacks play, 40,000 times! That's a lot of water!
The answer depends on where the water ends up. If the water ends up high on a mountain top then the snow may take a long time to melt. But the rain could also be sucked up by dirt and go into an underground lake called an aquifer. Then someone has to bring the water back up, so it could take a long, long, long time!
However, water that evaporated yesterday in the Pacific Ocean can make rain in California or Arizona in a few days. A drop might fall right back into the ocean and evaporate again the next day.
Some water pollution can happen through the water cycle process. Air pollution from burning things, or from your family car, can fall back to earth as dirty rain or snow. One source of water pollution can come from you and your family washing dishes, washing the car, washing your clothes and even taking a bath! You need clean dishes, clean clothes and you need to take a bath. But all of these things contain chemicals and they can pollute the water.
Because you, your family, and other families need clean water to drink and use around the house, there are people whose job it is to bring you clean water every day and to help get rid of your used dirty water. As you just learned, water is recycled through evaporation and rainfall, also called precipitation. Clean water collected in rivers, like Arizona's Colorado River, lakes and the underground lakes we call aquifers. All these sources of water are collected by people who work in water treatment plants. It is their job to collect the water that is brought in, clean it and then bring the clean water to the area you live in, including your house. To view the water treatment process click here.
These people who bring your water also check to make sure the water they bring to you is clean and safe to drink and use in cooking. Since we have to use water every day and that makes it dirty, we have experts, like the people who work at the Arizona Department of Environmental Quality, that check your water to make sure you and your family can safely use it.
Click here for a fun experiment you can try with the help of your parents to learn about the role of treatment plants in water filtration.