Erika Kahn
Science Fair Backboard Paper
Title: Solar Panels- distance and wavelength
Problem Statement: How does the distance from a light source and different
wavelengths of light affect the voltage output of a solar panel?
Hypothesis: I predict that the further away the solar panel is from the light source, the
lower the voltage output will be. Therefore, when the solar panel is 20 cm away from the
light source, it will produce the most voltage, and from 30 cm, it will produce the least. I
also predict that the red wavelength will produce the most voltage, and the blue
wavelength will produce the least.
Abstract: My experiment was performed to determine how different wavelengths
(colors) of light and the distance from the light source affect the voltage output of a solar
panel. My experiment included testing different distances between the solar panel and the
light source, and testing different colored filters on the solar panel to see how it affected
the voltage output. By performing this experiment, I found out that the farther away a
solar panel is from the light source, the lower its voltage output. I also found out that the
yellow filter (wavelength) proved to provide the highest voltage output, and the green
filter (wavelength) provided the least voltage output. My results have great importance
because they can help scientists understand the relationship between the distance the solar
panel is from the light source (sun), and how much voltage (electricity) it can produce. It
can also help scientists understand that different wavelengths (colors) produce different
amounts of energy.
Materials:
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1 large piece of green cellophane
1 large piece of blue cellophane
1 large piece of yellow cellophane
1 large piece of red cellophane
Scotch tape
1 portable work lamp
1 digital voltmeter
2 plugs for voltmeter
2 mini wires with ring terminals (these came with a kit)
2 long wires with ring terminals and alligator clips***
1 plastic solar panel stand (this came with a kit)
1 silicon mini solar panel (this came with a kit)
1 incandescent light bulb (100 watts)
Card table
Ruler
Work ladder
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4 cardboard design frames
*** These were constructed prior to my experiment
Procedure:
STEP 1: Set up a card table inside, preferably where there aren’t many windows.
STEP 2: Cut a colored piece of cellophane that is about 16 x 64 ½ cm. Fold this over on
itself two times, and then take one frame and tape the piece to it so that the whole middle
of the frame is covered. Trim with scissors when necessary. Repeat for the remaining
three colors of cellophane.
STEP 3: Take two mini wires, and use those to hook up the solar cells within the solar
panel. Connect one wire from post 2 to 3, and the other wire from post 4 to 5.
STEP 4: Take the two longer wires, and connect the ends that have the ring terminals to
posts 1 and 6, leaving the ends with the alligator clips hanging freely.
STEP 5: Set the solar panel up on its plastic stand. Then, grab a protractor and make sure
the solar panel is at a 45 degree angle.
STEP 6: Attach the ends of the two wires with the alligator clips to the two wires from
the voltmeter. Then, plug the voltmeter wires into the voltmeter.
STEP 7: Turn the voltmeter to the Vdc setting of 20.
STEP 8: Take a medium sized work ladder, and set the portable lamp up on it. The lamp
light should shine in the middle of the table. Then adjust the lamp and the solar panel so
the tip of the bulb and the middle line on the solar panel are exactly 20 cm apart.
STEP 9: Turn the lamp on.
STEP 10: Hold up the red, yellow, green, and blue filters against the solar panel one at a
time, making sure that the cardboard on the frame is not covering the solar cells. Record
the voltmeter readings for each color.
STEP 11: Readjust the lamp so that the tip of the bulb and the middle of the solar panel
are now 25 cm apart.
STEP 12: Hold up the red, yellow, green, and blue filters against the solar panel one at a
time, making sure that the cardboard on the frame is not covering the solar cells. Record
the voltmeter readings for each color.
STEP 13: Readjust the lamp so that the tip of the bulb and the middle line of the solar
panel are now 30 cm apart.
STEP 14: Hold up the red, yellow, green, and blue filters against the solar panel one at a
time, making sure that the cardboard on the frame is not covering the solar cells. Record
the voltmeter readings for each color.
STEP 15: Repeat the experiment ten more times (Repeat steps 7- 13)
Graph:
Conclusion:
After performing my experiment, and analyzing my data, I found out that the
smaller the distance between a solar panel and its light source, the higher the voltage. In
my experiment, the 20 centimeter distance produced the highest voltage average with
4.81 volts, 25 centimeters with an average of 4.47, and 30 centimeters with the lowest
voltage average of 4.21. I also found out that the yellow filter of light produced the
highest voltage output with an average of 4.52 volts, and that the green filter produced
the least voltage output with an average of 4.48 volts.
In my experiment, I have proven that the closer a solar panel is to its light source, the
higher its voltage output will be. I received these results because when the solar panel is
closer to the light bulb, the light given off is more concentrated, and the solar panel is in a
direct path of the light. But, when the solar panel is farther away from the light bulb, the
light becomes more spread out, and the solar panel is no longer in an exactly direct path
from the light bulb. My results prove this because at 20 centimeters away, the voltage
was higher (4.81 volts), and when the solar panel was 30 centimeters away from the light
source, the voltage was much lower (4.21).
In my experiment, I have found out that different colored filters also have an impact
on a solar panels voltage output. I have proven that a yellow colored filter (wavelength)
provides the highest voltage output (4.52 volts) and that the green filter (wavelength)
provides the least amount of voltage (4.48 volts). But, although these filters do have an
impact on a solar panels voltage output, this affect is very, very minimal. I believe I got
the results that I did because differently colored cellophane has different pigments, and
certain pigments can absorb more wavelengths (color) of light , and this caused certain
colored cellophane to absorb more colors of light that were produced by the light bulb.
To support this conclusion, my yellow cellophane had the highest average voltage output
of 4.52 volts, while the red and blue filters had an average voltage output of 4.50 volts,
and green had 4.48 volts. This leads me to believe that the yellow filter had a pigment
that was capable of absorbing more colors than the other colors of cellophane.
In conclusion, I have realized that my hypothesis was only partially proven. I
proved myself correct that the closer a solar panel is to its light source, the greater its
voltage output, and that the farther away a solar panel is from its light source, the lower
its voltage output. But, I proved myself incorrect that the red filter would produce the
greatest voltage output, and that the blue filter would produce the lowest voltage output.
My findings can help scientists, and just regular people, understand the relationship
between the distance from the light source and the solar panel, and also understand how
the wavelength (color) of light affects the output of a solar panel.