Solar Energy and Photovoltaics Background & Overview
When you think of solar power, you are probably thinking about photovoltaic
power, which uses special panels to directly turn sunlight into electricity.
There are many different ways to use the Sun’s energy but this is one of the
most common.
For this exercise you will be using a solar cell. When light hits the cell, the
energy it contains is transferred to electrons in the cell. Because of the way
the cell is constructed, the electrons can only move one direction. Together
they form an electrical current, which can be used to power devices such as
electric lights, motors, or computers. The amount of power generated by the
cell is proportional to the amount of power contained in the light, and this is
what you will be investigating today, using a device called an ammeter. This
device can measure the amount of current generated by the cell.
For this experiment, you will be measure the current generated by exposing
the cell to several different light sources:
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Incandescent light bulb
Compact fluorescent light bulb
“Blacklight” bulb
Colored light bulb
Full sunlight
Partial sunlight
You will be given a solar cell and an ammeter to take your measurements. For
each light source, you will measure the current generated using the meter
and record its value. When you have collected all of your data, make a graph
of the data and use it in your analysis.
Before you begin: Think about what is going to happen. What light source do
you think will generate the most power? What light source do you think will
generate the least? Write down how you think the different light sources
will rank in terms of the power they will generate, from highest to lowest.
Procedure
1. Prepare a table to record your data similar to the one shown below.
LIGHT SOURCE
Incandescent Bulb
Compact Fluorescent Bulb
Blacklight Bulb
Colored Light Bulb
Full Sunlight
Partial Sunlight
CURRENT (mA)
2. Get your solar cell and ammeter from your teacher.
3. Use the ammeter to measure current from each of the different
artificial light sources and write them down in your table.
4. Visit the teacher to make sure your ammeter is on the proper setting
for measuring full sunlight.
5. Go outside and use your ammeter to measure current from full sun and
partial sun, and write these down in your table.
Analysis
Make a graph of your current measurements to show the difference in
current generated by the different light sources. What are the independent
variable and dependent variable in this case?
Conclusions
Compare your measurements to your initial predictions. Were they correct?
If not, how close were you? What else do you notice about your results?
© 2010 John Bush, Colorado School of Mines GK-12 Learning Partnership, http://inside.mines.edu/~jobush/gk12
Support for this work is provided by the National Science Foundation’s Graduate Education, NSF, DGE-0638719
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free
Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no
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