Does the angle at which the Sun's rays fall on a solar cell affect the power that's produced?

How to Maximize Solar Energy

Hypothesis	I think that if the solar cell is placed perpendicular to the sun's rays, the power going to the cell will be maximized.
Abstract	When I was assigned this project, I decided to investigate whether solar power was really a feasible alternative to other sources of energy. I wanted to see if solar power could be used to charge batteries for other purposes, or to heat water, or operate machinery. As I considered these options, I wondered how I could maximize the efficiency of the sun and its rays. So, I decided this could be my experiment. So, the purpose of my experiment was to find the best way to maximize the efficiency of solar power. Once I had decided the purpose of my experiment, the next step was to formulate my hypothesis and choose how to test it in my experiment. My hypothesis then became, "If the sun is at a 90° angle with the solar cell, the amount of voltage received will be greater than if the sun is at any other angle with the solar cell." To then test this hypothesis, I created a set-up that allowed me to measure the voltage going to a solar cell when the sun was placed at different angles to the cell. When I finished conducting the experiment, I examined the data I had collected. I found that with my set-up, my hypothesis had not been correct. With the cell at a right angle to the ground, the energy was 4/5 volts. When it was at a right angle to the sun, however, it measured 3/5 volts. At other angles, it measured from 0 to 4/5 volts. Given this data, my conclusion is that my hypothesis is not accurate, and if I ever build a full scale solar cell, I will move the solar cell so that it is at right angles to the ground.
Materials	A solar cell, mounted using Three boards A fan Voltage Meter String Two Screws Protractor
Procedure	First, mount a fan and a solar cell on top of a board, which has been hinged to two other boards about 1/3 of the size of that. Next, bring them out on a sunny day. Move the third board so that it is at different angles with the sun. Measure the angle it is at with the ground. Use a votage meter to pick up hmuch energy you are receiving. Jot this down. Repeat the previous step as many timess necessary. Calculate for eah entry you have the angle with the sun's rays. Record which one was the most efficient, and which was least efficient. See if you can figure out why. Did it match your hypothesis?
Results	My results are listed in the table below.
Conclusion	I think the results of my experiment arenít logical. My hypothesis was that if the cell was perpendicular to the sun, the voltage would be maximized. The results, however, showed that when the cell was perpendicular to the ground, the voltage was maximized. Either my hypothesis had been false, or my experiment had been flawed. Itís not obvious, however, which of the two is true. The experiment could be improved by conducting it several different times on several days. It would have made my experiment more accurate by providing more results from which I could then compare. Even though my experiment proved my hypothesis wrong, it did prove that different angles collect different amounts of electricity.
Bibliography & Links	Dashefsky, H. Steven. Envonmental Science. TAB Books, Blue Ridge Summit, PA, 1994. Fredericks, Anthony D. Simple Nature Experiments with Everyday Materials. Sterling Publishing Co., NYC, NY, 1995. National Renewable Energy Labs. http://www.renewable.org/SUN.HTML. Last updated November 18, 1997.

Angle with Ground	Angle with Sun	Voltage
40°	-7°	0
60°	13°	3/5
70°	33°	3/5
90°	43°	4/5
110°	63°	3/5
120°	73°	2/5
140°	93°	3/5
180°	133°	3/5

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