The Nearly Unsuccessful Mousetrap Project

Project Overview: For a few weeks, we were given the task of creating a small wooden vehicle that would be propelled by the energy in a mousetrap. We could bring in our own wheels and materials to create unique, more effective designs. We had to select which size dowel rods to use, what size wheels, what diameter axles to use, among other things to design a vehicle that would travel the furthest.

Technological Concepts: At its most basic level, this project was about discovering the most efficient way to transfer the potential energy in a mousetrap into the kinetic energy of the vehicle, while minimizing energy lost to friction. Potential energy is "stored" energy, while kinetic energy is the energy of motion. Friction is two imperfect substances that rub against each other, dispersing energy in the form of heat. We also had to consider the diameter of the wheels (larger wheels take more energy to rotate) and the diameter of the axles, which would determine the wheel-to-axle ratio. Higher wheel-to-axle ratios were harder to rotate.

From the front

Learning Goals: We continued to apply the design process to decide which materials to use, and what size of materials to make the most effective design. However, a main focus of this project was learning how to use tools to speed up construction and improve products. We had to consider what the best tools were and learn the basics of safety for a variety of tools. A greater role of testing was emphasized in this project; often designs would not work very well at first or not at all, and all projects had to test to maximize the distance the vehicle would travel

Mousetrap Design: Our design utilized a single, thin piece of wood with holes bored through it for lightness. Small squares of wood were attached with holes drilled through for axles; records were implemented for the rear wheels with small plastic ones for the front. We attempted to minimize weight while still retaining a high wheel-to-axle ratio.

Positive feedback: Our design managed to go 32 feet, which we were satisfied with. Although it moved slowly, it moved very steadily. We were proud of this fact, considering our design did not even move initially; our testing phase was very effective. We also succeeded in minimizing weight throughout the vehicle.

 Redesign: The main thing we would have changed was the axle system. We found out that wood axles in wood frames created a large amount of friction. If done again, we would have used plastic for both, and then our design would have traveled far further. Furthermore, we could have lowered weight even further in the front wheels, which could have been thinner.

Technological Resources: We used three tools/machines: the belt sander, drill press, and mousetrap. Electrical energy was used to power the two tools. We used records and plastic for wheels, as well as wood for the axles and chassis. George and I created the vehicle, along with the guidance of Dr. Sartori, in the time of nearly three weeks from start to finish. We had to utilize new information on energy and friction, as well as safety precautions to construct the design.

Biggest Challenge: Beyond a doubt, our greatest challenge was fine tuning the length of the dowel rod to supply enough force to even move the vehicle, while still maximizing distance. At first (and for the next six tests) our design moved only five feet and sometimes not at all. To overcome this, we had to continually shorten the length of the dowel rod, and cut out part of the middle of the chassis to minimize weight. It took a long time before we were satisfied with the movement of the vehicle.

What we learned: We discovered how to use several tools to make more polished designs. We also had to apply concepts of energy perhaps even more so than in the previous project; if the science was flawed or ignored, the design would do poorly. We saw this many times from the other designs in the class, as many didn't even considered friction at all. Also, we learned that foresight is important -- once we had our friction generating wood axle implemented, we had no time to fix it.

The Model T extracted potential energy from gasoline, a magical proposition at the time