The objective: The goal is achieve the optimal amount of efficiency from harnessing solar radiation by altering which wavelengths of light in the electromagnetic spectrum are allowed to pass through the filters-therefore being absorbed by the solar cell and converted to clean, usable electricity.
Materials: 4 floppy disks, 5 Educational Solar Energy Kits (model 689), cellophane wrap in the colors primary blue, red, yellow, and clear, protractor, 2 Vernier LabQuest devices with portable chargers, 5 differential voltage probes, and a table with the height of 47 cm.
Make a series of silicon solar cells to form 5 panels composed of 4 cells each. Cover all with 2 filters that are specified from cell to cell that allow only certain light through to be absorbed.
The independent variable is the type of filter: red and blue to let through yellow light, clear-clear to be the control, floppy-disk filters to only let infrared through, yellow-blue to let wavelengths that make up red light, and red-yellow to allow blue light to pass through by reflecting red and yellow light.
The panels are wired to differential voltage probes to measure the direct current (DC) of the conversion of solar energy to electrical measured in volts (the dependent variable).
On a sunny day, the experimenters took measurements for about two hours in 75 degrees Fahrenheit weather.
Multiple sample trials were taken, prior to the experiment run consisting of 32 trials, to test if the solar panels are active.
Then record the statistical mean for each of the 5 solar panels for 32 one min. intervals.
Panel A covered by two clear filters results in the largest voltage output.
Panel F covered by red and blue filters was the next highes, and
Panel B, covered by yellow and red filters follow suit.
The fourth best was Panel E, covered by yellow and blue filters.
Panel D, covered by and infrared filter and a clear filter, had the least electrical output.
The hypothesis is invalid possibly because the filters were too thick and varied in density, the solar cells were not sensitive enough or were too old, or the exclusion of other forms of radiation decreases the absorption of solar energy therefore decreasing electrical output.
The Infrared, clear, and colored filters were used to determine if excluding certain wavelengths of light increase silicon solar cell efficiency.
Science Fair Project done By Veronica Murashige