Our task for this project was to use an alternate energy source to build a hybrid car, but that's not all. The car had to be able to travel exactly five meters then stop, while carrying an additional 250 grams. We also had to make a 3-5 minute pitch on our cars performance and its perks. After lots of thought we decided to use the elastic energy in rubber bands to make our car go five meters. We designed a frame and then calculated through trial and error how many times we would have to rap our rubber band around the cars axle to get the car to travel five meters and stop. My group enjoyed this project so much that half way through we decided to make another car and we would compare the efficiency of the two in the end. So we sketched up a blueprint for a solar car and started to build. Building and collecting data for two cars was very tricky to do in the time frame that we had so we had to do some work outside of school, but in the end it all payed off and we had two awesome cars that performed there task perfectly.
Here are our two cars working NOVA (solar car) is on the left RAZOR (spring powered car) is on the right
Here is our slide show presentation
Concepts We Used:
Spring Potential Energy- Energy stored in a spring or elastic by pulling or pushing it. We calculated the spring potential energy for the rubber band powering the car. It is calculated by PEe=1/2kx^2. x=distance moved by spring.
Spring Constant - A measure of how much a spring wants to pull back together or the rigidity of the spring. It is calculated by k=F/d. If it is easy to move, it would have a low spring constant, and if it were hard to move, it would have a high spring constant.
Thermal Energy - Energy created by heat, usually because of friction. It is calculated by total energy - KE - PE. On our performance graph, Our car started off with little thermal energy, but gained more as the car went farther, because it lost more and more potential and kinetic energy.
Reflection
During this project I learned that you need to be prepared for changes that might need to happen to make your car better. Our original car was going to have four wheels and be powered by springs, but half way through we decided the car would be more effective if it had three wheels and was powered by rubber bands and this ended up working very well. We fully built our solar car out of wood in the beginning, but then fully rebuilt it out of legos and it was more effective. Overall I learned to be flexible while building something.
Overall I think my group did a very good job with this project. We were able to create two cars that work good and we had a great time working with each other. For me nothing went poorly during this project. I liked how we were able to create two cars and still finish on time. I feel like for this project my group went above and beyond and exceeded our expectations. We all really enjoyed this project and put lots of time in at home as well as at school. We met up of out side of school three times to build, test, and perfect our cars.