For me this was one of the most fun projects that we did all year. Our task was to pick a project that we have did during the year and do it better. My group decided to redesign our hybrid car. For this project the task was to build a car that was energy efficient and use an alternate energy source to power it. We chose to use rubber bands to power our car. Last time we made a three wheeled car with one rubber band, but this time we made a four wheeled car with two rubber bands. Our new car was more aesthetically pleasing, more efficient, and more reliable. Once again to end goal was to make the car drive five meters and have it stop on the five meter mark. We decided that was kind over boring so we build a wall of wooden blocks three meters in and had our car smash through the wall and then stop on the five meter mark. This was a little tricky because we had to calculate how much the car slowed when it hit the wall, and then how much it accelerated after it hit the wall. In the end we got the car to smash through the wall and stop on five meters. This was a super fun twist to the project.
He is our slideshow presentation of our car. (Includes video of it working)
Concepts
Potential Energy (spring): How much energy a spring, or rubber band, is storing. Measures in Joules (J). We used this to calculate how much energy the rubber band car had before we released.
Kinetic Energy: Energy due to motion. Measured in Joules (J). We used this to see how much of our potential energy was converted to movement force.
Thermal Energy: The energy not converted to kinetic, and instead converted to things like sound and friction. Measured in Joules (J). We used this to see how ineffective our cars could be.
Spring Constant: How difficult it is to move a spring. the higher the spring constant, the harder it is to move. We used this to help us find out how difficult, or easy, it was to stretch our rubber bands.
Reflection
I thought that we definitely did this project better then before. It was so much more relaxing because we knew what we were doing and we had more knowledge of all the physics behind our car. In the end our car did something we never expected. We had it smash through a wall and still stop on the five meter mark! This made the project so much more fun and entertaining. Some things that our group did good on were our work ethic and productivity. We were constantly doing something. This time around we had two weeks less then last time to build the car! We knew if we didn't focus we wouldn't finish in time. Our work ethic was also very good. The car was a lot nicer and worked more smoothly then last time. Our slide show was also very clean. One thing that I learned was even if you don't have a whole lot of time to do something, If you buckle down and focus you can get it done. There were not pits during this project. I am very happy with how everything went and I couldn't ask to end the year in a better way!