Shake, Shake, Shake, Shake Your Flashlight

Any one who has a dad like mine, has already seen self-powered flashlights for a long time.  I mean, my dad is one of those that lives, I mean lives, at Home Depot or Lowes. And becuase he has that disturbing relationship with a store, like make of us girls do with our respective stores, I have seen every type of tool, old or new in my 21 years.  This includes that flashlight that you shake a little and, Voila! It lights up the room like you have 4 of those big circle batteries ( C or D) in it.  What a snazy little concept engineers in the world have thought of, an everyday product that we can all use without having to ruin the environment even more.

Okay so, the point of that little blurb was just to get you into the topic a little..  Now we get to the juicy stuff of generating electricity simpley by shaking a flashlight.. or having a turbine’s blades spin.  In class we did a lab that revolved around this concept of generating energy without having to harming the environment like with coal.  In the lab we had a flashlight that generated energy by shaking it back and forth.  We took the flashlight and attached it to the NXT ‘brain’ and that to the computer so that we could read the energy output from the flashlight.  Once we had everything hooked up we had to shake the light at 4 different paces, from no shaking, to slow, to fast.  With this we can see the difference that the pace and amount of shakes will make in creating energy.

During class we learned that the Faraday’s Law states that changing magnetic fluxes through coiled wires generate electricity (currents and voltage).  With running the laband creating the below spreadsheet and graph, we see that the more time we shook it in that 30 second interval of the NXT reading, the more energy we created.  This occurs because the more times the magnet within the flashlight passes the coil that is also in the flashlight, the more times the magnetic field has changed (or the polarity), and thus energy is created.  So if you shake the light 10 times in the 30 second interval, not much energy would be created becuase the magnet passes the coil only 10 times, but when you do it 70 times, the sum of the square of the shakes (becuase some numbers ended up negative, it was necessary to square it) is 112, a much higher voltage than with the lower amount of shakes.  The increasing motion of the trendline shows all of this in a simple visual.