1. Mousetrap Car TIPS View in full slide show mode and use headphones
/earbuds
For this project you and your partner will design and make a mouse trap car that will travel the greatest distance.

2. The magic of the mousetrap
Spring
In a mousetrap car, its motion comes from the spring in the mousetrap. It’s the spring that does the work. When the spring is stretched energy is stored. This is called Potential Energy. When the spring is released and allowed to work it creates Kinetic energy.
Bail Wire

3. Speed or distance
For more speed - Move the mousetrap closer to the drive axle. Make sure that the trap is not too close to the drive axle or the wheels will spin.
For more distance travelled – Move the mousetrap away from the drive axle.
                                                                                                     
Drive Axle
Think about where you will position the mousetrap for the result you want.

4. to the rear axel! This trap placement will give the car more speed.
Notice the trap close
to the rear axel! This trap placement will give the car more speed.
Notice how the position of the mousetrap here create 2 different outcomes.
Notice the trap far from the rear axel! This trap placement will give the car more distance.

5. Ideas for Increasing Distance
Increase Axle-to-Wheel Ratio
1. Use a larger drive wheel. The larger your drive-wheel the greater the distance your mousetrap car will travel per turn of the wheel.
2. Use a smaller drive axle. The larger the ratio of drive wheel(s)-to-axles diameter, the farther you mousetrap car will go for each turn of the wheel and the greater the pulling distance will be.
In this slide read the information and look at the difference in circumference between the wheel and the axle rod

6. Ideas for Increasing Speed Decrease Axle-to-Wheel Ratio
Decrease the axle to wheel ratio by adding tape to the drive axle or using smaller drive wheels.
2. Use a larger drive axle. The smaller the ratio of drive wheel(s)-to-axles diameter, the greater the acceleration that you will experience. Careful, if the ration is too small your vehicle will spin its wheels rather than accelerate.

7. Here are a variety of design ideas have a look at them

8. String & Lever arm Length
1. The string length should be a bit longer than the distance from the lever arm to the drive axle. This will allow the loop to release from the hook, preventing the string from rewinding. Do not permanently attach the string to the drive axle
                                                                                    
The length of the arm will determine the force developed to create motion.
A shorter arm – will have more initial force, give a fast start but not so good over distance.
A long arm – has less initial force and is good over distance. The lever arm can be made from a wood dowel – drill a hole at 1 end to fit the bail wire and glue in.

9. Friction
Friction – Imagine hopping onto your skateboard pushing off with your foot and riding without stopping, without having to push off again. You could ride continually until you decided to stop. Now come back to reality. There is an unseen force against all things that are in motion. Friction – it slows things down and eventually stops them.

10. Two kinds of Friction
• Static friction — the force that prevents motion
from occurring.
• Kinetic friction — the force that impedes a motion.

11. Wheels
If the hole of your wheels is bigger than the 1/8th inch axles you need an adapter. You can use a washer or small wheel hot glued to your wheel.
Wheel size: When designing vehicles for long distance travel you may want to consider larger diameter wheels. You can make wheels from discarded CDs. You can change traction on the wheels by changing the surface of the wheel with things like rubber bands, cut baloon strips or strips of abrasive paper glued to the wheel.

12. Insert the part from the bale in the top of the effort arm.
This is a possible design idea
A little hot glue holds it in.

13. How motion is created

14. Add cable tie to drive axle.
A cable tie can be used to create a string hook so the string can be wrapped around the axle. It is important that the string releases freely during vehicle operation.
Cable tie on axle
Cable tie trimmed to correct length

15. Greater distance can be achieved
Construct a light chassis – frame
Using a longer length lever arm
Have a large axle to large wheel ratio.
Reduce friction
Increase traction

16. What to do. Click on the link to view some long distance cars.
You can see lots of different designs by looking in Google images.
With your partner prepare design drawings for your vehicle. Side view and top view with measurement using pencil. Include a list of materials to be used and discuss with the teacher.