Important Concepts
Spring Potential Energy (PEspring=1/2kx^2)- A measure of how difficult it is to expand and compress the spring. Since we had two springs we hoped to have twice the amount of Spring Potential Energy. Kinetic Energy(KE=1/2mv^2)- Total Energy- The maximum amount of energy something has (potential energy). Velocity(v=change in d/change in t)-the rate of covered distance in a set of time. We use velocity in every project because we always have something moving and it takes time to get to its final destination. Spring Constant(F=kd)- a measure of how difficult it is to expand and compress a spring. Each spring has a unique spring constant even if it looks identical to another spring. Acceleration(a=change in v/change in t)- the change in velocity. Speeding up or slowing down. Our car briefly accelerated and then slowly decelerated as it slide across the ground. Law of Energy Conservation- Energy can not created or destroyed. It can only be transferred into different forms Thermal Energy- Friction creates thermal energy. |
This is our presentation script. Our car name is the Macchina de Corsa:
Z: Welcome and thank you for listening to our presentation. We are here to present our latest car design, the Macchina da corsa I5. D: It has many features that will appeal to buyers. Its sleek design is reminiscent of an italian sports car. In the Macchina da corsa you can feel cool in your everyday vehicle. M. In addition it’s dual power rubberband are made of a special formula only our company can use. The extra strength formula allows you to save money by not having to replace it and lets you get around faster. R: Another futuristic feature of the Macchina da corsa is its’ automatic parking space spotter. You can never find a space right where you need to go, instead of circling around and getting frustrated, the Macchina da corsa stops wherever the closest space is. The GPS is necessary for this feature to operate is not present on the prototype because it is still being developed. Z: The Macchina da corsa is cheap, low maintenance, and has easy to replace parts. SInce it is spring power it is also great for the environment. D: As you can see in our performance graphs, the Macchina da corsa creates high amounts of thermal energy to help it stop. This is also used in our secret and patented parking space spotter. M: Here is a slow motion video of our design in action. Take careful note of the tires and rubber bands unwinding. R: Unlike many other cars in its class, the Macchina da corsa uses a type of rubber like adhesive as a tire unlike a rubber band. This allows the tire to stay fixed into the wheel longer without the risk of breakage from the rubber band. Z: We will include two cartridges of the tire adhesive with each car purchase and it will be available for an affordable price in stores. This allows easy replacement without having to take it to the shop. This will improve customer satisfaction. D: The Macchina da corsa lightweight and flexible plywood body allows for easy portability. M: It also moves quietly and smoothly. R: We suggest investing in this idea now. Thank you for listening. |
For this project we had to engineer a small car using an alternative energy source. We could not use gasoline, nuclear, electric, or chemicals. The car had to roll 5 meters and then stop while carrying a 250g mass. For this project my team brainstormed possible energy sources like rubber bands, springs, baking soda and vinegar, and a wind turbine. After hearing what other groups planned to do and wanting to be different, we decided to use a propeller. We saw several youtube videos on successful designs but we still tried our own concept first. Our design had a plywood base and CD wheels. It was powered by three propeller toys like the ones in this picture. The propeller turned using a rubber band. Although, we eventually got the propellers to move, the car to not. So, we scrapped our initial design and instead used a water bottle as the base. Our second car still used the same propeller system. We hoped that it might work beacuse the second car is lighter than the first. We named it the clown car because it looks like a circus cannon. This car moved three inches. Since the clown car failed we designed a new car. This car was built off the base of a toy car. We still used a propeller but this time it was the propeller piece taken off an electric mini fan. It also used two small rubberbands. We hoped that using a hybrid design would make the car move. This car worked better if we added more weight. However, it only moved a few inches. we ended up also scrapp this design and built our final car. This car used two long rubber band chains to power it instead of a propeller. We modified our first car’s base and reused it in this car. We also used four sets of two CD for the wheels. After trial and error with this car and adjusting the rubber band placement, rubber band attachment, base shape, and wheels our car went four meters. Our final product used two long rubber band chains as the power. The wheels were two CD in the back and toy car wheels in the front. The front wheels did not rotate. We would have adjusted them if we had more time. The back wheels did not have enough traction at first so we added a strip of hot glue around the CD. This ended up being one of our best ideas because it made the car function. I am not pleased with the final product. I felt that if we had used a different energy source from the being instead of wasting our time we could have made our car go 5 meters. One of the most successful energy sources was a pulley. A pulley can be easily adjusted and is reliable. In the presentation we were told to “sell it”. We were supposed to imagine we were pitching our idea to Hyundai engineers. My team sold it by hiding the numbers and making up excuses. You can see our script at the left. I am embarrassed by this because I like being told facts with evidence and I did not do that in this presentation. We did get mostly positive reviews from our classmates though. The pros of this project was one of my teammates. She and I were great partners and are now friends. She also did a good job of keeping me positive. I dreaded our presentation because I felt embarrassed by it but she was not. She gave me some encouraging words of advice. From this project I learned how to quickly solve problems and when to evaluate a design. I also learned that thinking through ideas fully before building can be rewarding. I wish that my team had stopped and thought about the practicality of a propeller before starting to build. I also learned what hot glue can and can’t do. The cons of this project are obviously that it did not complete the task. I was not as positive and open-minded as I should have been and I am afraid that because me and one of my teammates were becoming friends that we left out our other two teammates. Another con is that, because we used so much hot glue in our design, I did not learn how to use materials like the drill and the saw. I did not learn how to work these on the the Rube Goldberg Machines either. Another factor was that Mr. Williams was not in class for most of the project so the timeline and productivity lagged. Although I am not proud of the results, I did learn a great deal about time management and how to thoughtfully layout a design from this project. I hope to apply these ideas in the future to avoid the mistakes made here.
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