This project was especially challenging and took a lot of trail and error. Having to come up with a simple, easy energy source was difficult and communication was key. My group especially had a tough time trying to communicate about what alternative energy we wanted to use. We first wanted to use solar power but realized none of us were skilled enough to power a car using that energy. Discussing more ides led us to our final energy source which in this case was rubber bands. We created three prototypes in total modifying each one as we continued to realize what would and wouldn't work. Our final product consisted of a wood, two axels, four wheels with rubber tires, screws, and a rubber band. Knowing how far the car must go and figuring out how much we spin the rubber band around the axle to reach that distance was difficult. Our group went through over one hundred rubber bands all of different length, thickness, and elasticity. CONCEPTS Velocity: is the rate of change of an object Momentum: is the product of the mass and velocity of an object Thermal Energy: is the part of the total potential energy and kinetic energy of an object Potential Energy: is stored energy Kinetic Energy: is energy that is in motion I believe my group worked really well together. We had really good ideas and tried to make all of them work but compromised if our plan did come out as we thought. Building took about a day in class and cost under ten dollars. My group could have worked on communication when it came to who was doing what and when. We were kind of all over the place trying to help with everything which didn't really help in the long run. We should have assigned people to certain tasks which they do best and could benefit the whole car or presentation. But overall we had very good time and our end product reached our goal.