Flashlight Lab

In this lab we used mechanically powered flashlights to show how electricity can be generated. The flashlight works like this: along the inside of the handle of the flashlight is a metal coil. Inside of the metal coil is a magnet. When you shake the flashlight the magnet slides back and forth through the coil generating electricity. This is the Faraday Principle of Electromagnetic Energy. The tight coil that the copper wire is wrapped in creates a magnetic field. As the magnet slides through the coil, it induces electron movement in the wire. Electrons change from positive to negative polarity as the magnet passes. As the rate at which the magnet passes increases, the movement of electrons, and therefore the amount of electricity produced also increases. Basically, the faster you shake the flashlight, the more power electricity is generated. The electricity is stored in a capacitor which powers the LED light.

In our experiment we tested different speeds of shaking the flashlight over a fixed period of time and the amounts of energy produced. We connected the flashlight to the computer which took a measurement of the electricity we produced every second. We tested our different speeds as shakes/second for periods of 30 seconds. We recorded the measurement as a single number- the sum of squares of voltages. This allows us to easily compare the measurements from the different rates. First we tested the flashlight held upright without shaking it. The measurement for that trial was .68 volts. Next we tested at a rate of 15 shakes/30 seconds. This resulted in a measurement of .67 volts. This does not seem to make much sense. It is attributed to human error as well as an imperfect experiment. Since the measurement was only taken every 1 second, the computer could be failing to report some of the energy created- basically bad timing. We also shook the flashlight too slowly. Due to other issues we were having with the computer, though, we chose to move on with the lab in order to save time rather than try to correct the mistake. The next test we did was at a rate of 30 shakes/30 seconds (1 shake/second). This resulted in a measurement of 105 volts. Our final test was at a rate of 45 shakes/30 seconds. This resulted in a measurement of 119.67 volts. This can also be seen in the graph below.