Experiments for children about energy can involve kinetic energy, thermal energy, electrical energy and solar energy. Many projects can be developed using ordinary household objects or objects that can be found at a department or hardware store. And a few can be carried out with toys.
Kinetic energy is energy that occurs when an object is moved or is set in motion. When your child lifts an object, she is using kinetic energy to move it. You can demonstrate the way kinetic energy transfers from one object to another by using balls or toy cars. To demonstrate transfer of kinetic energy using balls, first drop a large ball and a small ball together. Check how high each will bounce on their own. Then place the small ball atop the big ball, and drop them together with the small ball on top. Record how high the small ball bounces. Place a toy car on a track. Roll a second car down the track, and record how far it knocks the first car. Discuss how the energy from one object is transferred to the other.
Thermal energy can be used in many ways. To demonstrate how hot water can be made to do work, fill a Tupperware container about half full of water, and put a lid on the container. Ask your child to notice how the lid is flat across. Place the container in a microwave oven for one minute. Take it out, and discuss how the lid is now dome shaped. Next, place the container in a tub of ice. Discuss how the lid now turns into a shallow bowl shape.
Making a potato or lemon battery is an enjoyable way to learn about electrical energy. You'll need a potato or lemon, some salt, galvanized nails and some copper wire or pieces of copper scrap, two alligator clips and wire units, and a flashlight battery. To make a potato battery, stick a nail in one end of the potato and a piece of copper in the other end of the battery. Attach one alligator clip to the nail and the other one to the copper. Touch the other ends of the two clips and wire assemblies to the bottom of a flashlight battery to make it light up. The lemon battery works in much the same way, except that you cut the lemon in half, and sprinkle salt on it before inserting the two pieces of metal.
Heat and light from the sun can be used in many ways. One way solar energy is used is to make plants grow. Plants convert light into chlorophyll using photosynthesis. People can use solar rays to heat a cooker or their homes to make electrical energy. Your child can create a simple solar cooker by using a pair of scissors to cut a hole in the side of an aluminum can. Place a hot dog inside of it, and place the can on the hood of a car or on a metal slide on a sunny day. Have some fun with solar electricity by buying a small solar charger from a hardware or electronics store. You can use it to power a flashlight bulb by attaching an alligator and wire clip assembly to the solar cell and then to the bulb.