What is Energy?
Energy does things for us. It moves cars along the road and boats on the water. It bakes a cake in the oven and keeps ice frozen in the freezer. Energy makes our bodies grow and allows our minds to think. Energy is a doing, moving, working thing. Energy is the ability to do work. Here are a few forms of energy.
- Forms of Energy:
- Kinetic-- energy in motion
- Chemical-- energy stored in food, wood, coal, petroleum and other fuels.
- Electrical-- energy of moving electrons
- Radiant-- light
- Thermal-- heat
- Nuclear-- energy locked in the nucleus of the atom.
Sources of Energy:
Energy sources are classified into two groups: Renewable and Nonrenewable.
In the United States most of our energy comes from nonrenewable energy sources. Coal, petroleum, natural gas, propane, and uranium are nonrenewable because their supplies are limited. Renewable energy sources include biomass (trees), geothermal (heat from the earth), hydropower (water), solar (sun) and wind (air). They are called renewable energy sources because they are replenished in a short time.
- Biomass is any organic matter (anything that was once alive) that can be used as an energy source. Wood, crops, yard, and animal waste are examples of biomass. People have used biomass longer than any other energy source. For thousands of years, people have burned wood to heat their homes and cook their food. Biomass gets its energy from the sun. Plants absorb sunlight in a process called photosynthesis. Biomass is called a renewable energy source because we can grow more in a short period of time.
- Geothermal comes from the Greek word geo (earth) and thermal (heat). Geothermal energy is heat inside the earth. The inside of the earth is very hot. Sometimes this heat comes near the surface. We can use this heat to warm our homes. We can make electricity with it. Geothermal energy is everywhere under the ground. Geothermal energy is clean energy. No fuel is burned, so there is no pollution. We won’t run out of geothermal energy. It is a renewable.
- Hydro means water. Hydropower is energy we make with moving water. Moving water has a lot of energy. We use that energy to make electricity. The water on earth will always be there. We won’t run out of it. That’s why we call hydropower a renewable energy source. Hydropower is a clean source of energy.
- Solar energy is the energy from the sun. Solar energy is free and clean. There is enough for everyone. And we will never run out of it. Solar energy is renewable. The sun will keep making energy for millions of years.
- Wind is moving air. We can use the energy in wind to do work. As long as the sun shines, there will be winds on the earth. We will never run out of wind energy It is a renewable energy source. It is also free. We can use the wind energy to make electricity.