Life has always depended on energy, but until just a few hundred years ago that energy was mostly low level, unorganized, passive energy in the form of sunlight which is essential in plant growth. Sunlight is still one of the best sources of energy on the planet, but we no longer rely on the passive use of it. Now we collect it. You can try the solar energy experiments below to see how this is done.
The sun sends far more energy at us than we could use even in our most wild dreams. Energy is not in shortage in this world, only our ability to harness it is lacking. But we’re learning fast and one of the promising areas of development is in photovoltaics, used to capture sunlight energy and turn it into electrical energy. Other uses of solar energy include heating, water purification, and water treatment, plus more.
Solar Energy Experiment 1
You can experiment with solar energy by using photovoltaic cells, which are pretty inexpensive these days and can be purchased from Home Science Tools for about $8. Also purchase a small electric motor and some alligator clips.
- Attach the motor to the solar cell in a complete circular circuit.
- Set it out in the sun and watch the motor run off the sunlight.
If you hook more than one solar cell together in the circuit does that change how fast the motor runs? What if you shade the solar cell? What if you reflect more light at it? You can use a multimeter to test for actual volts, amps and so on coming from your solar cell.
Talk about how the solar cell works. Light is made up of real stuff that we call photons. Scientists aren’t even really sure of what a photon is or does or how it behaves, but we do know it’s there because we can see its effects. The photons hit the solar cell, which is made up of semiconductors (metals that move electrons in a controlled way). The semiconductors use the energy from the photons to move electrons through them. Moving electrons are electricity. If you connect the solar cell to wires then the electricity can flow through those wires to power any device you like. We’re really pretty good at making solar cells, it’s the batteries that get us. Storing that amount of energy in batteries for any length of time requires whole rooms full of batteries. But then a computer used to fill a whole room just a few decades ago and now your iPhone is more powerful than the computer that landed us on the moon . . . so who knows.
Solar Energy Experiment 2
Photovoltaic cells are black. Is this because black is so classic and so always in style or is there another, more practical reason? See if color affects heat absorption.
- Paint several different pop cans with different colors: black, white, pink, orange, and so on.
- Fill the cans 3/4 full of water.
- Place them in the sun and take their temperature using a thermometer. Take their temperature every 10 minutes for the next hour.
What difference does the color of the can make to energy absorption? Add in a black can with mirrors aimed to reflect the sun at it. (Be careful to have nothing flammable nearby; a call to 911 is probably not in the plan for today).
Solar Energy Experiment 3
Now you’re ready to make something work off your solar cell. Try making a car from paper packaging and Lego or K’nex wheels. A straw with a wire or wooden skewer running through it makes a great axle. You need a belt running from your little motor to your axle to make the wheels turn. Let your kids be creative and make up their own moving contraption using the belt and axle principle. It doesn’t necessarily have to do anything useful.
- Build a solar oven.
- Purify water using the power of the sun.
- Home Science Tools has many different kits to help kids learn about solar and other energy sources.
- Make a chart showing several different types of energy such as oil, coal, hydro power, nuclear power, and solar power. Write up the pros and cons of each type of energy after some research. Look at several sources for your information because people get really emotional about energy and are not always honest in their assessments.
- Learn where the sun gets its energy.
- Satellites of all types use solar energy to power them. In space the sun is always “on” and it’s really the only continuous source of energy available out there.
- When you take sunlight and make it into electricity you are converting energy from one form to another. Learn about energy conversion.
- Do this sunlight experiment.
- Some uses of solar energy are perfectly suited and others are more problematic. Is it easier to use solar energy to power a home or a car? Is it practical to power a factory? Is solar energy viable in every part of the world? Discuss the limits of solar energy and how using many different types of energy suited to a particular place and application makes sense.
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