Using the sun's energy directly is one way to use smaller amounts of fuels that can pollute our air and water. You can use the sun's rays to heat water, for example. Perhaps you've seen solar hot-water panels in your neighbors' backyards or on top of their houses. In this experiment, you can build a model solar collector and see how quickly the sun can warm an evening bath!
A shoe box with lid
Black crayon, magic marker, or spray paint
Clear plastic food wrap
Empty food or soup can
One or two thermometers
One or two magnifying makeup mirrors
Use a spoon to press down any jagged metal around the edge of the opened can. Then cover the rim with two layers of tape.
1. Using crayon, marker, or paint, color the outside of the shoebox and lid black. Do the same to the can. Then line the inside of the box and lid with foil (shiny side out) and fasten the foil with tape. Set one end of the lid into one end of the box as shown, then fasten with tape.
2. Fill the food can halfway with room- temperature water. Cover the can's top with plastic wrap and fasten it with the rubber band. Make a slit in the plastic wrap and insert the thermometer through it. Gently tape the slit shut around the thermometer.
Place the can inside the box as shown and add another thermometer if you'd like to measure the air temperature inside the solar collector. Then cover the front and sides of the collector with plastic wrap and fasten with tape.
4. Use a piece of graph paper to chart how quickly the water temperature and air temperatue rise over time. Later, you can use the magnifying makeup mirrors to reflect sunlight into the solar collector to see what effect they have on how hot it gets and how fast it heats up.
* r This working model solar collector is part of a series of science projects in WonderScience, published by the American Chemical Society and the American Institute of Physics. For more information, call 1-800-333-9511.