1-small solar photovoltaic cell (see example)
1-multimeter (see example)
Data sheet (see example)

Students will determine the amount of wattage per square inch using a solar photovoltaic cell.
 

• Students will place a solar cell on a flat surface in direct sunlight.

 
• The experiment must be conducted at solar noon. Solar noon is the midpoint between sunrise and sunset. You can find sunrise and sunset times here.

 
• Hook up a multimeter to the solar cell to measure the voltage and current. Refer to the diagram for an example of how to set up the circuit.

 
• Students will record the voltage (volts)  and current  (amps) from the multimeter. Make sure to convert current into amps. Most solar cell output is measured in milliamps. So you have to divide by 1000. Then calculate the power output for the solar cell in watts. [Volts x Amps = Watts]

 
• Students are to measure the area of the solar cell; only include the actual cell not the casing. Determine the power output of the solar cell in watts per square inch.

 
• Students are to repeat this procedure 10 times each day and determine the mean power output in watts per square inch.
• How much area (square inches) would the solar cells have to cover to provide enough power to a television and a Nintendo system in order to play? (assume the power rating of Nintendo is 19 watts and the power rating of a 19" color television is 300 watts)
• How many solar cells of this type would be needed to play Nintendo on the television?

 
• This step is to be repeated everyday for five days.

 
• Record all of this information along with your latitude and longitude in a spreadsheet and send as an e-mail attachment to solarenergy@netscape.com. You can send either a Clarisworks or Excel spreadsheet. See this data table as an example.

Once all of the data from the collaborating schools is compiled students  should graph the data and answer the following questions:
 

• How does the power output of the solar cells vary with the latitude and longitude?
• How does the number of solar cells needed to play Nintendo vary with latitude and longitude?
• What other factors might influence the results of this experiment?

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