Our next project this year was designing and building a hybrid car. The car had to have an alternative energy, meaning that the energy could not be chemical or nuclear. We then had to create a persuasive presentation to help sell our prototype to Hyundai. The requirements for the car were that it had to go 5 meters, carry 250 grams, and have an alternative energy.
My group decided to power our car with a rubber band. The car gets it's energy from the rubber band wrapping around the back axle. When wrapping around the axle, tension is created, which causes the car to move forward.
Concepts
Spring Constant (k): The measure of how easily a spring is compressed and expanded, measured in Newtons per meter (N/M).
Kinetic Energy: Energy due to motion, measured in joules (J).
Spring Potential Energy: Energy stored by the compression or expansion of a spring, measured in Joules (J).
Thermal Energy: Energy that comes from heat, measured in joules (J).
Power: The rate of work, measured in Watts (W) or horsepower (hp).
Energy Graph: This graph shows the car's different types of energy. The car starts with lots of potential energy, but as the rubber bands unwind, the car looses it's potential energy. The car started out with no kinetic energy, but as it continued to move and gain speed, it got more kinetic energy. The car started out with no thermal energy, but while it's wheels rubbed along the ground while moving, it gained more thermal energy. The total energy stays the same.
Distance vs. Time Graph: The car gained speed at first three meters, but slowly lost momentum when the rubber bands fell of the back axle.
Reflection
My group and I worked really well together when building our hybrid car. Though my grouped worked well, there were still problems that occurred during our construction. We had a difficult time figuring out the correct materials to use for our car. We started off using cardboard for the wheels and body of the car, but soon figured out it was not durable enough. Because of this, we had to rebuild our car halfway through the project. One way we could fix this is by researching what materials would be best before constructing our prototype. One issue I personally should work on is listening to and incorporating other people's ideas. One person in my group contributed ideas that were good, but ignored. In the end, we used her ideas halfway through the project. If we listened to her at the beginning of the project, we could have saved ourselves a lot of time and hassle.