Over View
In class, we had to come up with an alternate energy source to power a car. In groups, we had to brainstorm ideas for what to power the car with. In my group, which was made up of Casey, Jessica, Lara, and me, we decided to use the elastic energy in rubber bands to make our car go five meters. After lots of brainstorming, building, testing, and tweeking, we finally got our car to go exactly five meters. Here is the slide we made to present our car:
In class, we had to come up with an alternate energy source to power a car. In groups, we had to brainstorm ideas for what to power the car with. In my group, which was made up of Casey, Jessica, Lara, and me, we decided to use the elastic energy in rubber bands to make our car go five meters. After lots of brainstorming, building, testing, and tweeking, we finally got our car to go exactly five meters. Here is the slide we made to present our car:
Our car, the tricicar, took a lot of work to get it to where we could let it go at the starting line and have it stop at five meters. At first when we were brainstorming what we could power the car with, we thought we wanted to have it be wind powered with a fan attached to the back of the car and a sail directly in front of it. This proved to be a difficult thing to carry out though because the wind the fan would create might not be strong enough and there was also the issue of getting it to stop at five meters without physically turning off the fan, so in the end, we decided to swithch plans and use the tension of wound up rubber bands to power our car.
My group and I also decided to put only three wheels on the car. This made it more cost efficient yet still stable and fast.
Once we knew our power source and detailed schematics, we started to construct our car. First we got an axle with bearings. Then we cut the board to size and drilled a big hole near the back for the opening for the axle. We cut, sanded, and covered part of the wheels with gaff tape. Next we cut a slit in the wood for the front wheel and filed it down so the wheel could spin smoothly in it. This proved to be more dificult then we thought, but after an hour we did it. We then attached the axle with bearings to the underside of the board and made a long chain of rubber bands. After drilling a nail partially through the axle, we could finally test our car. My group and I placed the rubber band on the nail, tied the other end of the rubber band chain to one spot in the middle of the front of the car, and wound the chain by pulling the car back from the four meter mark. When we let our tricicar go, it fell short of the five meter mark by a meter and a half. We started to adjust our number of winds , but nothing was working. To fix the problem, instead of having the other end of the chain tied to one spot on the front of the board, we changed it to two spots. This added more rubber bands to be wound and there wasn't too much tension in one area of the chain, so it could go faster and farther. This method worked, and we got our car to go five meters. We finally finished our car.
My group and I also decided to put only three wheels on the car. This made it more cost efficient yet still stable and fast.
Once we knew our power source and detailed schematics, we started to construct our car. First we got an axle with bearings. Then we cut the board to size and drilled a big hole near the back for the opening for the axle. We cut, sanded, and covered part of the wheels with gaff tape. Next we cut a slit in the wood for the front wheel and filed it down so the wheel could spin smoothly in it. This proved to be more dificult then we thought, but after an hour we did it. We then attached the axle with bearings to the underside of the board and made a long chain of rubber bands. After drilling a nail partially through the axle, we could finally test our car. My group and I placed the rubber band on the nail, tied the other end of the rubber band chain to one spot in the middle of the front of the car, and wound the chain by pulling the car back from the four meter mark. When we let our tricicar go, it fell short of the five meter mark by a meter and a half. We started to adjust our number of winds , but nothing was working. To fix the problem, instead of having the other end of the chain tied to one spot on the front of the board, we changed it to two spots. This added more rubber bands to be wound and there wasn't too much tension in one area of the chain, so it could go faster and farther. This method worked, and we got our car to go five meters. We finally finished our car.
Concepts
Spring Potential Energy (PEspring)-Energy stored in a spring/ elastic by pulling or pushing it ex. The energy for my group's car was stored in the rubber bands
Kinetic Energy (KE)- Energy due to motion ex. When our car was moving it had Kinetic energy. At the one meter mark, it had a kinetic energy of 0.373 J
spring constant (k)- Measure of how much a spring wants to pull back together. Rigidity of spring. ex. After winding up the car and letting go, the rubber bands wants to pull back together, so it goes around the axle untill it reaches the other ends of the chain.
Thermal Energy (TE)- The energy that comes from heat. ex. the car's wheels against the floor creates friction, which is thermal energy, which causes the car to slow down and eventually stop.
velocity (v)- The rate of covered distance in a direction. To find it you use the equation distance over time.
ex. In one of my group's graphs, we compared distance vs. time, which means that the graph was showing velocity.
Reflection
Pits: I need to stop getting sidetracked and stay focused on my work better. I need to stop having off topic conversations and talk about the work that we do. I also need to work on my leadership skills. I have improved in this area since the begining of the year but I can still improve. I need to make sure everyone is participating in the group discussions, and help anyone if they don't understand what to do.
Peaks: My group worked well together. We all had fun working on the project and it turned out good. Another peak is that we got our car to run consistently . It stopped at five meters every time.
During this project I broke out of my shell a little bit. I am very shy and for this project, I was involved more and contributing more to discussions. I think this mainly because I was working with people I knew from previous classes. I need to work on contributing more to discussions even if I am not in a group with people I know. I also learned that I can do public speaking even if it made me a little nervous to stand in front of an audience. I actually really enjoyed presenting our car.
I had a lot of fun doing this project and learned so much from it. I hope I improve in my leadership skills and stay focused for the next project.