Learn about groundwater and the water cycle with an evaporation project and a water reservoir project.
To see for yourself what happens when water evaporates you will need a glass beaker and a sunny window. Evaporation is an important part of the water cycle.
*You could also use a tall glass if you don't have a beaker.
The water in the beaker seems to disappear the longer you leave it in the sun. This is not a magic trick. It's science! As the sun heated up the water in the cup, some of the water evaporated into a gas called water vapor. You can't see water vapor, but you can tell that the water has changed from a liquid to a gas because there is less liquid in the cup. Right before it rains there is water vapor inside clouds. When the weather is right the water vapor will come together and form raindrops. When the water vapor starts forming tiny drops of water we call it condensation. When condensation falls to earth as rain we call it precipitation. Sometimes the droplets freeze before they get to the ground and become hail, sleet, or snow!
Have you ever heard of groundwater? You can find out what it is by making your own with this project. We used the bottom of a terrarium, but any clear plastic container will work well.
The way you layered pebbles, sand, and soil made it possible for water to be held underground. As you learned in the previous experiment water can evaporate quickly. When it is stored underground water stays put. A reservoir is like a big container for water. Some reservoirs are man-made and the water might be kept there by a dam. Other reservoirs are natural. Water that is contained underground is called groundwater. Groundwater can provide water for a community by using wells. Groundwater might also slowly move through the ground, until it eventually ends up in a lake or river.
You've probably heard that it's good for the earth to recycle and may have even helped in recycling paper or plastic before. Did you know that the earth recycles too? Water that starts in a river or the ocean gets recycled by forming clouds in the sky then coming down as rain. Scientists guess that there is about the same amount of water on Earth today as when it was formed. The way water is continually reused is called the water cycle. The water cycle moves water between the earth and the air in constant circle or cycle. When water moves from the earth to the sky it is called evaporation. As the sun warms water, some of it will turn into a gas called water vapor. You can't see water vapor because it is too small.
Before it rains, there is water vapor inside clouds. The vapor collects inside the cloud and forms a raindrop. This is called condensation. You can sometimes see condensation on the top of a glass of ice water. When the weather is right, water drops will fall from the sky as rain. When water comes back to the earth like this it is called precipitation. Precipitation can also mean snow, sleet, or hail. The last step of the water cycle is transpiration, where water vapor is put into the air by humans that breathe it out, or by plants. Plants and animals give water back to the air. So do rivers, lakes, and oceans. Even though we can't see water vapor, there is always a little bit in the air around us. Every stream runs into a bigger stream, which runs into a river, which will eventually run to the ocean. All of these different bodies of water evaporate slowly, just like water in a cup that you've set out in the sun. Most water vapor comes from the ocean, since oceans cover so much of Earth.
What is Groundwater?
How do you think water gets from the ground after its rained to the rivers and oceans? Water that is stored in the ground is called groundwater. Have you ever heard of someone digging a well very deep in the ground until they get water? This is groundwater. Groundwater flows through the earth very slowly until it runs into a stream or other type of water (ponds, lakes, rivers). Because the water cycle is always moving water from one place to another, it can even carry water from one side of the world to the other. The water you drank today could have fallen as rain on China last year!
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