Does the Sun's Angle Affect the Output of a Solar Cell?
Talk It Over
A solar cell changes energy from the sun into electrical energy. Does the angle of the sun striking the solar cell affect how much electricity the cell puts out? How can you find out?
- Piece of cardboard, about 8½ in. x 11 in.
- Solar cell*
- Electrical tape
- Electrical tester* (with a 0-250mA DC range)
- Sunny day
- Modeling clay
- Drawing materials
- Glue the solar cell to the cardboard, black side down.
- Attach the red wire from the solar cell to the red lead from the electrical tester. Secure with electrical tape.
- Tape the black wire from the solar cell to the cardboard, with its bare end exposed. Make sure you can touch the bare wire with the tip of the black lead from the electrical tester.
- Outside on a sunny day, turn the solar cell toward the sun. Put a book under an end of the cardboard. Using the protractor, find a propping position that will put your solar cell at a 10° angle to the table or ground. If necessary, stabilize the cardboard with a lump of modeling clay.
- Turn on the electrical tester and set it to read in the 0–250mA DC range. Touch the black lead from the tester to the black wire from the solar cell. Read and record the number on the electrical tester.
- Reposition the solar cell at 20° and test again. Repeat for 30°, 40°, and so on until your cell is perpendicular to the ground at 90°.
Never look at the sun. It can blind you. Wear sunscreen, hat, and protective clothing whenever you are in the sun. The sun's radiation causes wrinkling, spotting, and skin cancer.
Get an adult's help with setting up the cell, using the protractor, and reading the tester. Test your solar cell at 30°, 60°, and 90° only.
The angle of incidence is only one of many factors that affect the output of a solar, or photovoltaic, cell. (It is not the angle of the cell in relation to the ground that we used in this experiment, but the angle of the sun's rays falling on the solar cell.)
Design and carry out experiments to determine how other variables, such as air temperature, clouds, shade, reflective surfaces, and compass direction, change the output of your solar cell.
Show Your Results
Put your electrical tester readings in a data table like this for "Go Easy":
|Angle||Output (in mA)|
For "Go," add rows for the other angles you tried. For both "Go Easy" and "Go," make a bar or line graph that shows how the solar cell's output (on the vertical axis) changes with the angle (on the horizontal axis). Write a few sentences summarizing any differences you observed and explaining the reasons for them.
For "Go Far," make data tables and graphs for the variables you measure. State conclusions about how each factor you studied affects solar cell output.
Tips and Tricks
- This experiment works best on a day without clouds. Find a sunny spot where no obstacles shade your solar cell.
- You'll have better data and a better project if you repeat this procedure several times and average your results.
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.