I bet you’re wondering how this whole mousetrap car project relates to the wonderful world of physics. Well, chances are that you AREN’T wondering, since you’re Mr. McMahon and you’re supposed to know about all this cool physics stuff, but we’re going to tell you about it anyways! The things that make this car related to physics are energy, friction, mass vs. acceleration, and The Law of Conservation of Energy.
The first thing that we’re going to enlighten you with is the whole role of energy for our car. Obviously without energy, the car wouldn’t have gone anywhere and we would have gotten an F on this project. But since energy is, of course, involved we didn’t fail. J The energy in the car is located in the spring of the mousetrap in the form of potential energy, which is energy capable of having energy, if that makes sense. This potential energy is transformed into kinetic energy, which is energy in motion, by pulling back the metal piece connected to the spring and releasing it. (Be careful because it doesn’t feel so great when you get your finger caught in it.) Once the spring is released, the car moves!
The next way that this wonderful project is related to physics is the whole mass vs. acceleration deal. Obviously, the lighter that the car is the more acceleration it is going to have and the easier it’s going to be to move the car. If you never paid attention to what Mr. McMahon said then you might have made the mistake of making a heavy car, which would have much less acceleration. Think of it this way. Try pushing a mini cooper collector’s toy. Now try pushing an 18 wheeler. See the difference?
Next is friction. How does friction play a role in this crazy assignment? You might ask. Well, first let’s start off by saying that friction is causes by the rubbing together of the surfaces of two objects. Remember when Mr. McMahon tried pushing the heavy file cabinet across the tile? Yeah, friction played a role in that. Now pertaining to the mousetrap car, the friction that we need is the friction between the wheels of the car and the floor. Of course, if we would have learned more about friction BEFORE we tried using tiny dollar store wheels, we would have avoided the problem of our back wheels spinning out completely. But we learned the hard way. Like we learned, if you don’t have enough friction between the wheels and the floor, the wheels will simply spin out and the car will not accelerate anywhere. It’s annoying. Trust me. Another way that friction could affect the movement of the car is the friction between the axel and the wheel. If there was too much friction between the axel and the wheel, then the axel would spin at a slower rate, causing the car to move a shorter distance. Sure this helps solve the problem of the wheels spinning out, but it still doesn’t make the car go anywhere. So all in all, you need just the right amount of friction between the wheels and the floor, the axel and the wheels, and the string and the axel.
And last but certainly not least. The Law of Conservation of Energy, which states that energy cannot be created or destroyed, but that it can be transferred and can change forms. The mousetrap car is the perfect example of this when the potential energy changes to kinetic energy, causing the car to go. Oh, and remember how we told you that one of our problems was that the wheels kept annoyingly spinning out? This was another transformation of energy. The energy was transformed into thermal energy.
So in conclusion, we learned that this car runs on friction, potential and kinetic energy, mass vs. acceleration, and demonstrates the Law of Conservation of Energy. How about that? Maybe we should send this idea to Ford and see what they think of it. Cars that don’t run on fossil fuels and therefore don’t pollute the atmosphere, and therefore stop global warming, cool huh?