Q: (Initially posted on January 22, 2003) FROM MENTEE SHANNON L. IN NJ
In my Women in Engineering class, we are participating in a mousetrap car
derby, in which we are suppose to design a car that is powered only by a
mouse trap. We will get points on its straightness and its distance. Could
someone please send some ideas that would help us design a vehicle powered
by the spring of a mousetrap? I am specifically interested in how the mousetrap can power a car.

January 27, 2003
A: FROM MENTOR BARBARA KONTOGIANNIS IN CO
You may also want to consider extending the mechanism - like adding a
longer lever arm to the moving part of the mousetrap. You can get the
drive energy over a longer period of time this way, and the length helps
stablize the car. Same principles as already described - the lever pulls a
string wrapped around the back axel of the car. A long lightweight car can
work. I made one of these in high school, using balsa wood and small wheels
from a toy car and set the speed record for my class! There are multiple
solutions - have fun with it.
Janurary 24, 2003
A: FROM MENTOR DEBORAH GRUBBE IN DE
Use the mousetrap lever spring as the main propulsion mechanism. Wrap a
string around the drive axle of your car, making sure that the axle spins
freely and without a lot of friction. Attach the other end of the string
to the lever arm of the mouse trap, and set it so it releases slowly. To
reduce friction, look for a way to loosely hold the axle and its wheels in
place.
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A: FROM MENTOR JACQUELYN JURGA IN MA
Hi Shannon-
The mousetrap as the excelerator for a car sounds like a fun challenge.
Were you given a mouse trap or do you need to purchase one? My first
advice if you can purchase your own is to find a style that is strong, and
has a good spring. The assignment says it can only be powered by a mouse
trap.... so one of the main features of your car could be very good ball
bearing wheels that will take off quickly and stay turning after the
initial 'snap' of the spring. That should satisfy the distance challenge.
Those wheels should not be the type that swivel. Install them so they are
straight on the car so it travels only straight for the next part of the
assignment. If you can get your hands on an old fashioned rollerskate (the
kind with 4 wheels, two in front and two in back)it would be a great start
to making your car. Those old skates are heavy enough to withstand that
initial snap of the mouse trap. A lightweight car might flip over. I am
writing this without knowing what your mousetrap looks like... but I think
it should be attached to the back of your car so it gives a good 'push'
when you snap the trap. Be aware that the trap has moving parts that can
get in the way of the cars traction. Install the trap in such a way that
when it snaps the spring parts do not interfere with the travel. In other
words, that the bar that moves does not get in the way of the wheels or
touches the floor which would slow the car down. Mouse traps can be
unpredictable. If there is a way to place channels or guards to make it
snap the same way every time - you will be better off. If you can find a
skate, making the top part of the car might be as easy as using an old used
toy car that you take the wheels off and glue onto the skate. With regard
to how the mousetrap will power the car is that it will give the car a
'push' when you snap the trap. Your wheels will have to do the rest. Now,
that also poses a question to your teacher. Ask how many times you can
snap the trap? Only once? Or shall the design get more detailed in as much
as having opposing springs to keep it going? If your car wants to flip
when the trap snaps, consider making a starting block for the car to send
it on its way safely. That starting block might be like a ramp to give the
car more chance for distance. I do not know if that would be allowed, so
ask your teacher first. Try not to forget the details like giving it a
custom paint job to distinguish yours from anyone else's. I hope my
rambling has been of some help. Enjoy the assignment - it sounds like so
much fun. Good Luck.