5 uses of solar energy
Our earth gets most of its energy from the sun. We call this energy solar energy. Sol means sun. Solar energy travels from the sun to the earth in rays. Some are light rays that we can see. Some are rays we can’t see, like x-rays. Energy in rays is called radiant energy. The sun is a giant ball of gas. It sends out huge rays of energy every day.
Most of the rays go off into space. Only a small part reaches the earth. When the rays reach the earth, some bounce off clouds back into space—the rays are reflected. The earth absorbs most of the solar energy and turns it into heat. This heat warms the earth and the air around it—the atmosphere. Without the sun, we couldn’t live on the earth—it would be too cold.
We Use Solar Energy
We use solar energy in many ways. During the day, we use sunlight to see what we are doing and where we are going.
Plants use the light from the sun to grow. Plants absorb (take in) the solar energy and use it to grow. The plants keep some of the solar energy in their roots, fruits, and leaves. They store it as chemical energy. This process is called photosynthesis. The energy stored in plants feeds every living thing on the earth. When we eat plants and food made from plants, we store the energy in our bodies.
We use the energy to grow and move. We use it to pump our blood, think, see, hear, taste, smell and feel. We use energy for everything we do. The energy in the meat that we eat also comes from plants. Animals eat plants to grow. They store the plants’ energy in their bodies.
We also use the energy stored in plants to make heat. We burn wood in campfires and fireplaces. Early humans burned wood to provide light, cook food, scare away wild animals, and keep warm. Solar energy transforms, or changes, into heat when it hits objects.
That’s why we feel warmer in the sun than in the shade. The light from the sun turns into heat when it hits our clothes or our skin. We use the sun’s energy to cook food and dry our clothes.
Solar Energy is Important
People, plants, and animals use solar energy for light, heat, and food. Solar energy is also important to nature.
Solar energy powers the water cycle. The water cycle is how water moves through the atmosphere and the earth’s surface. The sun heats water on the earth. The water evaporates— it turns into a gas called water vapor and rises into the air to form clouds. The air in the atmosphere is cool. The water vapor condenses into liquid water.
The water falls from the clouds as precipitation—rain, sleet, hail or snow. When water falls on high ground, gravity pulls it to lower ground. There is energy in the moving water. We can capture that energy with dams and use it to make electricity.
Solar energy makes the winds that blow over the earth. The sun shines down on the earth. Some parts of the surface heat up faster than others. Land, for example, usually heats more quickly than water. The air over the land gets warm. The warm air rises. The cooler air over the water moves in where the warm air was.
This moving air is wind. Wind turbines can capture the wind’s energy. The wind turbines turn the energy in moving air into electricity. The wind pushes against the blades of the turbine and they begin to spin. A generator inside the turbine changes the motion into electricity.
Coal, oil, and natural gas are called fossil fuels, because they were made from prehistoric plants and animals. The energy in the plants and animals came from the sun. We use the energy in fossil fuels to cook our food, warm our homes, run our cars, and make electricity. Most of the energy we use today comes from fossil fuels.
Solar Energy is Renewable
Solar energy is free and clean. Solar energy is renewable. We will not run out of it. The sun will keep making energy for millions of years. Why don’t we use the sun for all our energy needs? We don’t have the technology to do it yet. The hard part is capturing the sun’s energy. Only a little bit reaches any one place. On a cloudy day, most of the solar energy never reaches the ground at all.
Post time: 06-07-2017