Project Outline

• 1. Design a mousetrap powered car with the materials available.

  2. Standard sized mousetrap, approx 1 week timeline.

Research

The main goal of the mousetrap car is to travel the longest distance possible. There are many things which can affect the performance of the car.

Tip: This was learned the hard way: make your mousetrap car as light as possible. Do not use metal parts, instead, Balsa wood is recommended.

The most important part of the car is the mousetrap. Since the mousetrap offers a limited source of power, and it can only be wound once, it is important to harness as much mechanical energy as possible from the springs located inside.

To do this, The spring lever should be extended as far back as possible, while keeping it within the 40.5cm length regulation. This will allow the power source (mousetrap) to accelerate the vehicle over a longer period of time, as it will provide more resistance to the trap’s initial motion. The mousetrap should also be placed closer to the front of the vehicle, so the lever used can be as long as possible.

The second largest challenge will be reducing the car’s overall friction, which includes designing two axles which allow the car to move freely. Friction is a force which resists the lateral motion of a surface. Lubricating the car’s axle will result in less resistance, allowing the car to move farther.

In an attempt to minimize the surface area between the wheels and the ground, my mousetrap car was designed with three wheels, each as thin as possible. The back axle was also created with metal (aluminum) bushings, since they provide less friction and can be lubricated. The back axle itself was created with wood, as it is a light weight material. The front axle was made of metal (see warning below), again because it provides less friction against the wheel and can be easily lubricated.

Warning: The metal axle was too heavy, therefore either use aluminum or wooden axles, while avoiding heavier metals.

To increase the traveling distance, a few other techniques can be used. These include:

• Large drive wheel to axle ratio

The larger the ratio the farther the car will travel, since one axle rotation is equal to one wheel rotation.

Warning: If it's too large, the car wont move. Experiment with this aspect to find the perfect ratio.

• Using smooth wheels

Smooth wheels are more efficient and allow a mousetrap car to travel further than knobby tires, even if they have less traction with the ground. If the ground was uneven and rough, knobby tires would be a great choice. In this competition the tires would use up too much of the limited energy source available.

Tip: CDs work well.