## Science and Engineering Blogpost #4

Reflection

Elastic potential energy is stored when the elastic band is wrapped around the axle. The more times the elastic band is wrapped around the axle the more potential energy there is. The axel is turned when the car is pulled backward. When released, the elastic band unwinds, thus making the axle and the wheels attached to the axle move as well. As the wheels move, most of the energy is transformed into kinetic energy, a very minute amount of the energy is transformed into thermal energy because of friction that is created when the axles and wheels turn. Once the elastic band has fully unwound, there is still momentum in the wheels as it carries further, so the car -itself- turns the axel in the opposite direction. When the car momentarily stops, as it catches itself, is the last part of where the potential energy is higher than the kinetic energy. The wheels catch themselves as the band won’t wrap itself any more around the axle. Thus the car is pulled back a little bit by the leftover kinetic energy.

I was successful in creating a product that is very effective, simple, and light. In the final product, there was almost no unnecessary weight to drag the car down. The cardboard in the final product is very light but very sturdy. There could possibly be more distance gained when the car moves, by the change in the length or type of elastic band chosen. An issue that arose while I made different prototypes was the rebound the car had; the car would go back after going forwards. In the final model, I was able to almost eliminate this through the usage of an elastic band rather than a rubber band.

There are some areas where I could improve this model. One is that the back left wheel (at the beginning of the video, the wheel that is fully in view in the top right corner) is wobbly, and not well connected. The connection between the wheels and the car should be stronger. A stronger base would probably be better too, as it would deduct the possibility of being broken. More time to hopefully be able to take out the rebound would have been better to make this product more efficient. I could have also made a top for this car, so it looks better and visual aesthetic for children.

If it were to be sold to a child though, it wouldn’t be as cool, flashy, or as small as other toy cars. But if it were in a pack in which the child would create the car I think it would do better, as it is very simple and straight forward. I believe that a child would also take more care of a toy and enjoy the toy longer, especially if they made it themselves, this is speaking from my own experience as a child.

Environmentally this would probably be sustainable, there are all kinds of different options one can choose to use to replace certain parts of the car. Most of the parts are very common and can be from recycled items. Also, this car doesn’t use any electrical energy, thus not producing any unwanted pollution. I would say though, that the wheels used to create the car, would be the hardest part for one to replace or use, as bottle caps aren’t very good as wheels. Overall this car is very versatile with the parts that are used to create it is very unique.

If this product was to be further I think that it would have a positive impact on the clients as when they begin building the cart, they would probably try out different methods and see how it changes the results of the cart. Along with the fact that the basic design is very simple, a lot of creativity is allowed for the kids to add on what they want. Overall I think that this would be a very good and fun opportunity for young children to try out and play around with the car.

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