What It's All About
Energy is invisible, but you can see all of the wonderful things energy makes possible. From making your body move to powering computers, energy is life!
Energy, Energy, Everywhere
Sources of energy are all around us. In fact, almost everything has hidden energy potential, and the different forms of energy serve different purposes. Energy for a person is different than energy for an automobile. Can you think of some sources of energy? Here are some examples:
The light from the sun is pure energy, and many other sources of energy originally got their energy from the sun. For example, plants turn sunlight into leaves, flowers, and fruits. Animals eat the plants, changing the energy in the leaves and fruits into body mass. When animals die, they decompose; after a very, very long time, their energy turns into oil, coal, or natural gas. That's why these sources of energy are called fossil fuels. Sunlight is also used to charge solar cells. These panels are like batteries that are charged by sunlight.
Food gets its energy from the sun, but then people eat it to get their own energy. Food is digested and then the energy in it is used to make the heart beat and the blood pump, which keeps the whole body working.
Where does wood come from? It comes from trees, which are big plants that have absorbed energy from the sun. When wood is burned, it releases its energy as heat.
Coal, oil, and natural gas are the most common sources of energy. All of them are burned to create heat, electricity, or fuel for vehicles. But they take thousands of years to create. People are using them much faster than they can naturally form. Consequently, they are limited in supply and are running out. These fuels can also be hard to find or mine, and they cause a lot of pollution.
Water is used to create energy. The flow of water is used to push turbines that create electricity. This is called hydroelectric power.
Wind can be used to turn windmills, which generate electricity.
Nuclear power comes from a radioactive ore called uranium. Radioactive materials store more energy than any other source, but radioactive waste is extremely dangerous. Exposure to radioactive materials can result in mutations, illness, or even death.
Garbage can be burned at waste-to-energy facilities. The fire warms pipes of water, which create steam to generate electricity.
Chemical reactions can create energy. For example, batteries create energy through chemical reactions, but after a while the reactions stop and the battery dies.
Since people are using energy all the time, it easily goes unnoticed. Try to get your students thinking about when they use energy. Even when you are done with your energy unit, you may want to sprinkle in energy awareness and energy conservation tips throughout the year.
Almost everything has energy or can be used to help create it. It's just hard to get the energy out and put it to work. Explore energy sources even more by making a potato battery. You will need:
One low-voltage LED clock
Two zinc-coated galvanized nails
One large potato, halved
Two short pieces of copper wire or two pennies
Three long pieces of insulated copper wire
Here is how you generate power from the potato:
Remove the battery from the clock.
Poke a nail into each half of the potato.
Poke a piece of copper wire (or penny) into each potato. The wire and nail should not touch.
Use a long piece of wire to connect the copper wire of one potato to the positive (+) terminal of the clock's battery compartment.
Use another wire to connect the nail in the other potato to the negative (–) terminal in the clock's battery compartment.
Use the third wire to connect the nail in one potato to the copper wire in the other potato.
Voilà! Set your clock. Try the experiment with other foods like lemons or pickles. Can you light a light bulb? What else could you try to power?
The kind of energy the human body runs on is called caloric energy. How many calories a day do you need to be healthy? Can you find where calories are listed on food packaging? Can you keep track for one day and see if you are eating too much or too little?
Energy Alphabet
Depending on the grade level you teach, you may already have a science unit on energy as a part of your annual curriculum. If so, try to integrate concepts of energy conservation and renewable energy into your existing curriculum. If not, try this crash course in energy. Select several books about energy to read with your class. Some fun options include Charlie Brown's Encyclopedia of Energy by Charles Schulz, Dorling Kindersley's Eyewitness Books: Electricity, Dorling Kindersley's Eyewitness Books: Energy, Why Should I Save Energy by Jen Green and Mike Gordon, and Energy and Power by Rosie Harlow and Sally Morgan.
Have your students write an ABC book that can be shared with other classes and kept in your school library. First, have the class brainstorm energy-related words or concepts for each letter of the alphabet. For example, A is for alternative energy, B is for battery, C is for circuit. You may need to provide examples for some of the harder letters. Q could be for quit wasting energy, and Z could be for zap. Assign one page for each student. They should first draft the text and show it to you for editing. Each page should include the letter and what it stands for, as well as an explanation of the word or concept. Once you have approved what they have written, they can write it on their page along with a colorful drawing illustrating the word or concept.
