This 2 x 4 cm calibrated silicon solar cell is rated to produce a specific open-circuit voltage and short-circuit current in 1 Peak Sun (1000W per square meter) of solar insolation. For silicon solar cells, the current output is almost linear to the amount of light. So, for example, a calibrated cell rated to produce 200 mA in 1 Peak Sun will produce about 100 mA in 1/2 Peak Sun, and about 50 mA in 1/4 Peak Sun.
You can take your solar science project to another level by using this calibrated cell to measure the actual level of light during your experiment! Measure how fast a motor can lift a weight in different levels of sunlight! Or, compare two different solar panels in the same level of sunlight. You can also learn how the level of sunlight varies with the angle of the solar panel. Have fun!