What exactly is a watt? Can you feel it? If you remember from your last physics class, you could say it is a unit of power, one Joule per second, or a rate of energy usage. All of these answers are correct, of course, but what do they mean? How can we relate to a watt? This is the question we asked over a year ago. This question led to the development of an educational tool that would demonstrate — in a very physical way — power and energy. It was the start of our bicycle powered generators project.
I am an engineering student because I enjoy solving problems, especially in a hands-on way, but I also love sharing this experience with anyone who finds it interesting, which is why the educational element of the bicycle-powered generators project is what made me so excited about being involved. Our product was going to educate individuals about power and energy, which are two concepts that perpetually affect the world, yet are often quite mysterious.
With the hope of providing a little clarity, a group of engineering students and I have designed and constructed a bicycle-powered charging station. This is a stationary bicycle that generates electricity and uses the electricity to charge your cell phones or iPods.
The beauty of the charging station, though, is that it also displays in real time the amount of power that you are generating while you pedal, and it shows you the total amount of energy that you generated when you are done. It shows you how much power is being used to charge your phone, and the nearby display shows how much power several common devices use. Can you pedal fast enough to light a lightbulb? Definitely. An Xbox? Most likely. A blow dryer? Definitely not.
The charging station is now on display in the engineering building here on the Northern Arizona University (NAU) campus. My hopes are these:
First, that the users will internalize a little bit of knowledge about power and energy. I hope that the project will make them begin to think about how much energy they use, and consider how they might reduce it.
Second, that this project will motivate students to accomplish projects outside of class. I hope that they will get involved with an organization such as Wind for Schools or work with university organizations like the Green Fund (both of which were integral parts of this project) to gain support for their own ideas.
About the Author: Matthew Petney is a senior studying mechanical engineering at Northern Arizona University. This year, Matt is supporting the USDA/NRCS-funded solar-powered irrigation system on the Navajo Reservation, and he also helps with a Wind for Schools program that works with middle and high school students to construct bicycle-powered generators and bicycle-powered blenders. He is currently pursuing the Fulbright scholarship, among others, in order to continue work with a prosthetics clinic in Bolivia for the year after graduating from NAU.