|Show Number 902|
Peggy learns how a solar car is made and follows the General Motors Solar Car Sunrayce.
Solar power comes from the energy of our Sun, a yellow dwarf star located 93 million miles from the Earth. It is a middle-aged, mid-size star compared to the billions of other stars in the universe.
The interior of the Sun is a region very high in temperature and filled with dense gases. The Sun's core is estimated to be approximately 27 million degrees Fahrenheit. Heat and light from the Sun are produced through a process called nuclear fusion.
Sunlight is an excellent energy source and the future of using solar power is very exciting. The Sun's energy can be used to heat and cool buildings, generate electricity, operate communication and navigation systems and even power solar cars, like the ones in the General Motors Solar Car Sunrayce featured in the Newton's Apple segment!
Solar-powered cars all get their fuel from the same place - the Sun. The cars use hundreds of photovoltaic cells to convert sunlight into electricity. Each cell produces about one-half volt of electricity.
When the Sunrayce teams design their electrical systems they have to allow for variations in sunlight. The Sun's energy powers the car's motor and charges a battery for use when the Sun is hidden by a cloud. If a car is designed to put all of its energy toward driving and keeps nothing in reserve, it will stop completely in cloudy weather. If too much energy is diverted to the battery, the engine runs too slowly to keep up in the race.
Engineers and scientists still have many questions and problems to tackle before solar power becomes an efficient and economical way to fuel vehicles. But as the demand on fossil fuel resources increases, research will continue to search for alternative energy sources, including harnessing the Sun's energy to drive a vehicle. The most exciting part of using solar power as an energy source is that it is pollution free and inexhaustible. If research continues, one day solar energy may replace today's combustion engine cars!
Solar--Referring to the Sun.
Solar Collector--An object that gathers the Sun's energy.
Nuclear Fusion--The process by which the Sun produces heat and light.
Fossil Fuels--Coal, oil and natural gas. Substances that have been formed by the decay of the remains of ancient plants and animals - in a sense they are a form of "buried sunshine."
Solar Panel--A device that captures the Sun's energy so it can be used for heating and other purposes.
You can build your own solar powered cars and race them just like in the GM Solar Car Sunrayce!
Build a custom-designed vehicle propelled by photovoltaic cells.
1. Place the solar cells side by side.
2. Connect them in a series by twisting the negative and the positive wire of one cell to the next cell.
3. Attach the motor to the remaining positive and negative wires.
4. Attach the propeller to the motor. Observe how fast it turns.
5. Design a custom body for the car. Compare your's with your classmates'.
6. Try a few time trials to see whoÕs car is fastest. How can you modify your car to make it go faster?
1. What would happen if you used more cells? Does placement of the cells affect the power of the motor?
2. Does the arrangement of the cells affect the design of your car? How could you arrange the cells to make the car more efficient?
3. Do you have any solar-powered items at home? Where else could solar cells be used at home? At school?
*Adapted with permission from materials of the Science Weekly.
Investigate other uses of solar power. Contact your local utility company and ask them about solar heating and cooling systems. Compare the costs of using solar power to natural gas and electricity. Prepare an annual budget and see which energy source is the most economical.
Discover how light and heat can be used as energy. Try filling one pie pan half full with white sand and another half full with dark soil. Insert a thermometer in each pan with the bulb just below the surface. Record the temperatures for both pans. Place pans at an equal distance under a lamp with a 150-watt light bulb. Turn the light on and wait for five minutes. Test the temperature in both pans and record your findings. Are the pans the same temperature? What would happen if the pans were further away from the light? How could scientists use this energy?
A radiometer is an instrument that measures radiant energy. See if your school has one you can use to study light. What happens if it is put in front of a light source? If you block the light with your hand, what happens? What kind of energy do the moving vanes have? Why are the vanes black and white? What powers the radiometer?
Color can change the amount of light and heat that are absorbed. Find out which colors are the most receptive. Paint a few tin cans different colors. Make sure you use matt paints or ones that aren't too shiny. Fill each can with equal amounts of water. Using a thermometer, record the temperature in each can. Allow them to sit in the sun for a few minutes. Test the temperatures in the cans and then arrange them in a rainbow from coolest to hottest. Now that you know which colors are coolest, what colors will you wear in the summer from now on? What about the winter? What color would you pick to paint your house to save energy?
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