One excellent idea is to create a miniature "hybrid" renewable energy power plant. This could be accomplished by combining solar cells and a small windmill kit. Such an idea could graphically demonstrate the complementary nature of these two free power sources.

cience Fairs are a great time for kids to learn about the scientific method and to try their hand at creating interesting projects. Often the projects end up being the same ones you and I probably did when we were kids (the ubiquitous bubbling volcano, anyone?)

Why not do something more original-and more green! Renewable energy sources such as solar power, wind power, geothermal, and hydro are chock full of cutting edge science ideas that make perfect projects.

Solar energy can also provide many science fair ideas. These range from solar ovens and solar stovetops to solar photovoltaic (PV) cells that produce electricity. Once again, some simple searches on the Internet can yield free plans and inexpensive sources of parts for such experiments. An example of a good solar electricity experiment would be to connect PV cells in series or in parallel and measure voltage and current under different sunlight intensities (for a more controlled experiment a bright lamp could be used). You will find that some combinations yield the optimal output in lower light and others are optimal in stronger light conditions. Another idea would be to graph the power output at different angles. For this you simply need a plastic protractor to measure the angle of the cell relative to the light source.

One excellent idea is to create a miniature "hybrid" renewable energy power plant. This could be accomplished by combining solar cells and a small windmill kit. Such an idea could graphically demonstrate the complementary nature of these two free power sources. For example, the sun is less intense during winter, yet in most places wind is more intense in the cold season, because air is denser and weather patterns favor wind. The sun does not shine during storms, but often wind is very strong during stormy weather. A combination of solar and wind may yield more consistent energy output… Sounds like a good hypothesis for a science fair project!

Another interesting line of research involves a device called the thermoelectric generator (TEG). A TEG converts heat directly into electricity without moving parts. Such devices are currently used to power deep space missions and provide power for teams exploring remote areas of the earth. While not as efficient as mechanical generators, the lack of moving parts, low weight, and high reliability of these devices makes them ideal for these applications. TEG devices can be built from scratch simply by twisting pairs of certain types of wire together (try nichrome and copper), or can be bought commercially for only a few dollars (look for "Peltier" modules). A small heat source such as a candle can generate a significant voltage. (But be sure to check with the school first before using a source of fire, adult supervision is mandatory). One example of a winning science fair idea would be to construct a TEG and "fuel" it with solar energy, and to compare this to a traditional solar cell. To be effective, the solar energy must be concentrated using either a solar cooker type reflector or a fresnel lens (but be careful not to overheat a commercial TEG-don't focus the solar energy to a tiny dot but keep it somewhat diffused). Another project idea is to show how waste heat in a house or factory could be captured and put to good use by a TEG, offsetting fossil fuel usage.

Some other forms of renewable energy might be harder to construct for an average science fair student, but for advanced students may be possible. Examples would include small wave power and geothermal energy projects. Some of the kits mentioned earlier could be used in these projects with suitable modifications. For example, the small windmill kit has an alternator that could be slightly modified to be powered from water power. A TEG could be used to illustrate geothermal energy production, perhaps by placing it inside a pyrex beaker filled with sand and heating the bottom of the beaker to simulate the heat deep within the earth.

So, banish the clay volcanoes this year and make your next science fair project interesting, topical, and green. You might just power your way to a first prize!

About the Author

J. Stephen Pendergrast is the founder of Picoturbine.com, a web site devoted to renewable energy educational materials, including free plans with science fair and science project ideas.