Mousetrap Propulsion
Student Sheet(s)

Materials

Materials can vary; this list is just an example of what your group may need:
·  Mousetrap
·  Body of the car: wood scraps, balsa wood, craft sticks, foam, coat hanger wire
·  Car axles: dowel rods, metal tubes, coat hangar wire
·  Wheels: various metal lids, wheels from old toys, CD’s
·  Pull cord: String, fishing line
·  Tools: pliers, hammers, handsaws, drills
·  Super glue
·  Hot glue gun and glue sticks
·  Old ball bearings (from old roller blades or skates)
·  Rubber bands
·  Various kinds of tape (transparent, masking, duct)

Procedure

1.  Your group will be creating a car that is propelled by a mousetrap.
2.  Before you begin construction of your car, discuss some of the following aspects of your car with your group. Create a sketch of the design you decide on.
a.  Propulsion: Transferring energy is quite simple. You can start by attaching a dowel rod to the arm of the mousetrap. Tie a string to the end of the dowel and then wrap the other end around one of the car’s axles. When the mousetrap is released, it pulls the string and propels the car. Try varying the length of the rod to increase speed or distance.
b.  Chassis: The chassis is the body of your car. It will hold the mousetrap and the axles. You need to decide on a shape that is aerodynamic and lightweight. You must decide what the chassis will be made out of and how you will shape it.
c.  Axles: The axles of your car should be lightweight, but strong. To make them turn freely, use bearings that are attached to the chassis of your car. Be careful not to get any glue on the face of the ball bearing!
d.  Wheels: Old CDs make great wheels. Try stretching a rubber band around the edge to give them added traction.
e.  Pullcord: Your pullcord must be strong so the force put on it by the mousetrap does not break it.
f.  Alignment: If your mousetrap car steers to one side, your speeds and distances won’t be very good. Be sure your wheels remain aligned.
3.  Once your group has a sketch, show it to your teacher and explain how your car will work. Listen to any suggestions your teacher may have, and if necessary, modify your design. Sketches are due Friday May 9, 2008.
4.  Begin construction of your car! Be especially careful with the tools and glue!
5.  Once your car is complete, fill in the pre-race data sheet.
6.  When time and your teacher permits, do three trial runs with your mousetrap car. Fill in the Test Day Data Sheet. If possible, make changes to your car. Note them on the Data Sheet.
7.  When you have completed the construction and testing of your mousetrap car, complete the Mousetrap Car Question sheet.
8.  On race day, compete against the other teams in your class. Good Luck!
Mousetrap Car Example
This mousetrap car was built for a distance competition.


Pre-Race Data Sheet

Group members’ names:______
______
Name of mousetrap car: ______
Materials used:
Sketch of finished car:

Test Day Data Sheet

Group members’ names:______
______
Distance Table

Distance

Trial 1
Trial 2
Trial 3
What problems did your car experience?
What can be done to improve your mousetrap car’s performance?
Mousetrap Car Questions
1.  Your mousetrap car uses potential energy. Where is this energy stored? Be specific.
2.  How would a car designed for distance differ from one designed for speed?
3.  Fill in the blanks in the following table:
Distance (meters) / Time (seconds) / Speed (m/s)
Trial 1 / 4.00 / 7.1
Trial 2 / 4.00 / 6.2
Trial 3 / 4.00 / 6.8
Average Speed
4.  What is a momentum of a 325 gram mousetrap car traveling at 1.3 m/s? (Remember to convert mass to kilograms!) (momentum = mass x speed)
5.  If the mousetrap car begins from a stop and reaches 2.5 m/s in 10 seconds, what was the acceleration of the car? (acceleration = change in speed ⁄ time)
6.  How does friction affect the efficiency of a mousetrap car?