A shake flashlight, which utilizes a magnet traveling between coiled copper wire to create an electric current, was the basis for our experiment.
Background/Purpose
In our electricity generator lab, we were tasked with studying the effects of one of the most important physical laws regarding electricity: Faraday’s Law. The law states that, “changing magnetic fluxes through coiled wires generates electricity (currents and voltage). The greater the change in magnetic flux, the greater are the currents and voltages.” The purpose of this lab was to see how Faraday’s Law affected the electricity generated by increasing the magnetic flux in a shake flashlight. It was hypothesized that as the flux was increased (by increasing the rate of shaking the flashlight), the electricity generated would also increase.
Materials
The NXT robot, a modified shake flashlight that channeled its electric current through two wires rather than to a light bulb, and alligator clips on a cord that can be plugged into NXT. A Labview program and Excel spreadsheet was already set up for us before class to record all of our data automatically with each test.
Procedure
- Hook up the shake flashlight’s wires to the alligator clips
- Hook up the clips to the NXT, hook up the NXT to the computer
- Open the Labview program that will track the voltage generated by the shaking flashlight over a set period of time
- Perform three tests: Once without shaking the flashlight, once shaking it 25 times (slower rate of shaking), and lastly by shaking it 50 times (fast rate of shaking)
- Calculate the sum squared of voltages produced with Excel and graph the results
Results
As seen in the screenshot above, the results confirmed our hypothesis. Negligible electricity was produced when the flashlight was left static. Any electricity created from this control test can be chalked up to residual charge left within the magnet and coil. The next test was a light to medium shaking rate of 25 shakes in the allotted testing time. The results of the sum of voltages squared showed this increase of activity really created a huge jump in the amount of electricity produced. Finally, in our final trial, shaking the flashlight 50 times at a constant and fast rate produced by far the most electricity. This experiment helped demonstrate that Faraday’s Law is just that, scientific law. It is experiments like this one that brought about my blog’s name: science, it works.