The Water Cycle
One of the reasons why the planet earth can sustain life is because it has water. Almost all living things need water in one way or another. The earth is in fact covered in 70% of ocean water. That's a lot of water! Plus that percentage does not include the water found on land, in the earth, and the water trapped in the ice caps. All in all, the earth has about 326 million trillion gallons of water!
So what happens to all this water? Well, it goes around in what could very be one of the most ancient cycles on the planet, the water cycle. The water cycle consists of four stages which basically takes water up from the earth, stores them in the air, and then allows the water to come back down to the earth in different areas. Studying the water cycle is one of the easiest home science experiments for kids, and there are actually many ways you can recreate the cycle!
The first stage of the cycle is evaporation. This is when the water from the earth is turned into water vapor or steam due to the heat of the sun. Sometimes, the heat of the earth which allows steam to come up from the earth also contributes to the water cycle. The water we see is not the only water that the heat can “collect” though. When we humans sweat, our sweat can evaporate and join the water cycle. Plants, which store water in their leaves, can transpirate their water stores and this water can join the water cycle as well. Transpiration is one of the ways the water from deep within the earth (what plants and tress drink) can be harvested for the cycle.
The second stage of the cycle is called condensation. When the water vapor in the air condenses together, it forms clouds. Condensation turns the water vapor back into liquid, but within the clouds. You can conduct one of the home science experiments for kids everyday by studying the process of condensation. When you get a cold soda from the refrigerator, you are used to seeing water droplets form around the glass or container of the soda. The water came from the air! The air around your soda is warmer than the soda itself, so the water vapor in the air condenses back into liquid in the cooler areas, which is around your soda bottle. This is also what happens in the clouds. Since it's much cooler up there, the water turns back to liquid.
The third stage of the water cycle is precipitation. You are probably familiar with this term from studying the weather. Precipitation is when the water in the clouds gets too heavy and it falls down like rain, snow, sleet, or hail. By now, the clouds have probably been moved by the wind, and place where the water falls like rain is not necessarily where the cycle had begun its evaporation! As a result, water circulates around the earth. Now that's amazing!
Finally, the fourth stage of the water cycle is the collection of water back into the earth's oceans, bodies of water, and ground. In the projects section of the site, you will find one of the easiest home science experiments for kids that will give you a good idea of exactly what happens in the water cycle!