How to make a mousetrap car with cds

Engineering Design Project

MATERIALS

1. Four wooden wheels

2. 6 paper clips

3. Corrugated cardboard

4. One wooden dowel

5. 12” length of 3/16” steel rod

6. 8 ½” times 11” piece of corrugated cardboard

7. 2’ piece of fishing line

8. 4 eye hooks

9. Masking or duct tape 2 6” pieces

Procedure

1. Cut a piece of cardboard so that it is slightly bigger than mousetrap by about ½” on every side.

2. Use duct tape to attach mousetrap to the base, care not to cover up spring in the middle of the trap

3. Screw the four eye hooks onto the bottom of the cardboard chasis, one in each corner. Ensure they are aligned with each other

4. Insert one wooden dowel into the front eye hooks to act as the front axle. This is the set of eye hooks directly under the mousetrap.

5. Insert the metal rod into the back eye hooks to act as the back axle. This will be the axle rotating the wheels with link to the mouse trap.

6. Put wheels and hold them into place using paper clips to tighten them in.

7. Tie fishing line tightly to snapper arm and to the back axle of the racer, opposite the snapper arm tightly again. This is done when the mousetrap snapper is fully stretched.

8. The mousetrap snapper is then stretched to a desired degree then the back axle is wound until all hanging fishing line is tightly wound around the back axle.

9. Step 8 is then repeated at that given angle three times to get accuracy before moving to a different angle.

REPORT

OBJECTIVE

The objective of this project is to make a mousetrap racer which travels and stays in a designated area. The objective emphasizes on accuracy of the racer to stop after a constant distance is covered. The project will utilize potential energy in form of torsional energy in the wound spring of a mousetrap then convert it to kinetic energy in the wheel axle until friction causes it to stop. The experiment measures the accuracy of our racer in a given angle of release therefore its accuracy.

While varying the degree of wounding the project can also go on to investigate effect of change in mousetrap lever arm to distance travelled by the racer. The degree of lever arm is changed then racer distance is measured, this is then compared to a bigger degree of lever arm release increasing the degrees constantly then comparing it to distance moved by the racer. This will give an indication of the relationship between lever arm degree and energy output.

DESIGN CRITERIA AND BACKGROUND

The design used is meant to be simple and stable at the same time. In some designs a piece of rod was added to the link between mousetrap and wheel axle, this provided much power to the racer than in our model. Our objective was however not for power but for accuracy which the rod would not improve on. This design utilizes materials used to create an accurate racer.

The materials chosen had a specific reason as to why. I chose a wooden wheel rather than using a lighter CD because wood will offer more traction as opposed to plastic. Traction is important for it to move especially on tile floor. To ensure constant distance travelled by the racer I used a fishing line which is stronger than a simple string, the distance travelled will also be constant therefore accurate because during winding only a specific length of the line can be wound therefore making distance travelled to be same and accurate.

The constrain realized was that wind continuous winding the mousetrap losses some of its potential energy stored in the spring so with time the distance travelled will lessen therefore making it less accurate. The general principle used in this project is minimizing weight and creating stable racer. This is proven by the removal of the elongated lever arm while at the same time creating a balance between the need to reduce weight and need to increase stability. This made us come to the conclusion that as much as CDs reduce weight the need for stability provided by wooden wheels is far important. The team also tried to increase friction by using wooden wheels instead of CDs so as to increase traction creating movement of the racer.

Previously there were three models which were not implemented. The first model was made of CDs in all wheels. This model was not working well because the wheels offered little friction, it just skidded over the floor. CDs were also not stable they would move sideways a lot, the problem was solved by using wooden wheels. The second model only the back wheels were wooden the front had CDs. This model was aimed at providing both stability (wooden wheels) and lighter weight/ more speed (CDs). However on the actual model was clumsier than the one originally made of only CDs. The third model had only wooden dowels in all axles which resulted in a relatively slower racer, when this was changed to a metal rod which was slimmer the racer moved faster. This was aimed at reducing friction during its rolling; the small circumference spun by the string also propels the racer a much greater distance with small amounts of energy.

DESIGN

This was the team’s initial sketch on a piece of paper. The side view illustrates what the racer will look like as it is racing. It has direction of the tires as a result of the snapping of the mousetrap.

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RREFFERENCES

Aden .J. (2012). Mousetrap Cars: Propulsion. Retrieved from http://www.docfizzix.com/topics/design-basics/MouseTrap-Cars/mousetrap-propulsion.shtml

Ideas-Inspire (2016). Mousetrap cars. Retrieved from http://ideas-inspire.com/mousetrap-cars/

Instructables (n.d). Mousetrap Car. Retrieved from http://www.instructables.com/id/Mouse-Trap-car/