Windmills harness wind power to generate electricity, pump water and grind grain. Test how a model windmill reacts to wind from different directions. Follow the instructions at the Science Buddies website for building a model windmill. Modify the experiment to determine the smallest amount of wind required to turn the blades. Change the types of materials used to make the blades to determine how this affects the energy generated. Test the windmill to determine the fastest wind possible before the windmill is damaged. Research different types of windmills and wind generators to determine the most efficient shape and style for local conditions. Investigate the historical uses of windmills and how designs have changed over time.
Build a model hydroelectric generator to illustrate the use of water to create electricity. Directions for a simple model are available at the Re-Energy California website. Vary the speed of the water used to generate electricity to determine the effect. Change the density of the water by adding sugar according to the directions at the California State Science Fair Project website. Determine if this change in density affects the wattage output of the generator. Test a variety of non-soluble substances such as sand and mud to determine the effect on the electricity produced. Research the different ways to use water to generate electricity. Include micro hydro electricity, wave power, tidal power and blue energy. Information is available at the Julian Trubin website.
The sun creates power daily that can be used in both passive and active energy systems. Build a solar oven with the directions at the Energyquest website. Test the power of the sun to heat the inside of a car by checking the temperature hourly from early in the morning to late in the afternoon. Research the effect these temperatures have on items left in a car. Investigate active solar heating sources and design a home that uses active and passive solar power. Older students can design a home that uses several alternative energy sources to eliminate the need for commercial electricity.