A super-fast, super-cool car that uses the pent-up energy inside a mouse trap spring to propel a homemade car forward. While normally this is reserved for high school physics classes, it really is a fun and inexpensive experiment to do with kids of all ages.
This is a great demonstration of how energy changes form. At first, the energy was stored in the spring of the mousetrap as elastic potential energy, but after the trap is triggered, the energy is transformed into kinetic energy as rotation of the wheels.
Remember with the First Law of Thermodynamics: energy can’t be created or destroyed, but it CAN change forms. And in this case, it goes from elastic potential energy to kinetic energy.
There’s enough variation in design to really see the difference in the performance of your vehicle. If you change the size of the wheels for example, you’ll really see a difference in how far it travels. If you change the size of the wheel axle, your speed is going to change. If you alter the size of the lever arm, both your speed and distance will change. It's fun to play with the different variables to find the best vehicle you can build with your materials!
Here's what you need to do this project:
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Materials:
Since the directions for this project are complex, it’s really best to watch the instructions on the video. Here are the highlights:
1. Tape the dowel to the outside of the wire on the mousetrap car (see image below). When the mousetrap spans closed, the dowel whips through the air along with it in an arc.
2. Attach a length of fishing line to the other end of the dowel. Don’t cut the fishing line yet.
3. Attach one straw near each end of a block of foam using hot glue.
4. Insert a skewer into each straw. Insert a wheel onto each end of the skewer. This is your wheel-axel assembly.
5. The wheels on one side should be close to the straw, the wheels on the other end should have a 1/2” gap.
6. Thread the end of the fishing line around the wheels with the gap as shown in the video.
7. Load the mousetrap car by spinning the back wheels as you set the trap.
8. Trigger the mousetrap with a pen (never use your fingers!). The dowel pulls the fishing line, unrolling it from the axel and spinning the wheels as it opens.
Energy has a number of different forms; kinetic, potential, thermal, chemical, electrical, electrochemical, electromagnetic, sound and nuclear. All of which measure the ability of an object or system to do work on another object or system.
In the physics books, energy is the ability to do work. Work is the exertion of force over a distance. A force is a push or a pull.
So, work is when something gets pushed or pulled over a distance against a force. Mathematically:
Work = Force x Distance or W = F d
Let me give you a few examples: If I was to lift an apple up a flight of stairs, I would be doing work. I would be moving the apple against the force of gravity over a distance. However, if I were to push against a wall with all my might, and if the wall never moved, I would be doing no work because the wall never moved. (There was a force, but no distance.)
Another way to look at this, is to say that work is done if energy is changed. By pushing on the non-moving wall, no energy is changed in the wall. If I lift the apple up a flight of stairs however, the apple now has more potential energy then it had when it started. The apple’s energy has changed, so work has been done.
All the different forms of energy can be broken down into two categories: potential and kinetic energy.
My students have nicknamed potential energy the “could” energy. The battery “could” power the flashlight. The light “could” turn on. I “could” make a sound. That ball “could” fall off the wall. That candy bar “could” give me energy.
Potential energy is the energy that something has that can be released. For example, the battery has the potential energy to light the bulb of the flashlight if the flashlight is turned on and the energy is released from the battery. Your legs have the potential energy to make you hop up and down if you want to release that energy (like you do whenever it’s time to do science!). The fuel in a gas tank has the potential energy to make the car move.
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This is a great demonstration of how energy changes form. At first, the energy was stored in the spring of the mousetrap as elastic potential energy, but after the trap is triggered, the energy is transformed into kinetic energy as rotation of the wheels.
Remember with the First Law of Thermodynamics: energy can’t be created or destroyed, but it CAN change forms. And in this case, it goes from elastic potential energy to kinetic energy.
There’s enough variation in design to really see the difference in the performance of your vehicle. If you change the size of the wheels for example, you’ll really see a difference in how far it travels. If you change the size of the wheel axle, your speed is going to change. If you alter the size of the lever arm, both your speed and distance will change. It's fun to play with the different variables to find the best vehicle you can build with your materials!
Here's what you need to do this project:
[am4show have='p8;p9;p100;' guest_error='Guest error message' user_error='User error message' ]
Materials:
- Mousetrap (NOT a rat trap)
- Foam block or piece of cardboard
- Four old CDs
- Thin string or fishing line
- Wood dowel or long, straight piece from a wire coat hanger (use pliers to straighten it)
- Straw
- Two wood skewers (that fit inside straw)
- Hot glue gun
- Duct tape
- Scissors
- Four caps to water bottles
- Drill
- Razor with adult help
Since the directions for this project are complex, it’s really best to watch the instructions on the video. Here are the highlights:
1. Tape the dowel to the outside of the wire on the mousetrap car (see image below). When the mousetrap spans closed, the dowel whips through the air along with it in an arc.
2. Attach a length of fishing line to the other end of the dowel. Don’t cut the fishing line yet.
3. Attach one straw near each end of a block of foam using hot glue.
4. Insert a skewer into each straw. Insert a wheel onto each end of the skewer. This is your wheel-axel assembly.
5. The wheels on one side should be close to the straw, the wheels on the other end should have a 1/2” gap.
6. Thread the end of the fishing line around the wheels with the gap as shown in the video.
7. Load the mousetrap car by spinning the back wheels as you set the trap.
8. Trigger the mousetrap with a pen (never use your fingers!). The dowel pulls the fishing line, unrolling it from the axel and spinning the wheels as it opens.
What’s Going On?
Energy has a number of different forms; kinetic, potential, thermal, chemical, electrical, electrochemical, electromagnetic, sound and nuclear. All of which measure the ability of an object or system to do work on another object or system.
In the physics books, energy is the ability to do work. Work is the exertion of force over a distance. A force is a push or a pull.
So, work is when something gets pushed or pulled over a distance against a force. Mathematically:
Work = Force x Distance or W = F d
Let me give you a few examples: If I was to lift an apple up a flight of stairs, I would be doing work. I would be moving the apple against the force of gravity over a distance. However, if I were to push against a wall with all my might, and if the wall never moved, I would be doing no work because the wall never moved. (There was a force, but no distance.)
Another way to look at this, is to say that work is done if energy is changed. By pushing on the non-moving wall, no energy is changed in the wall. If I lift the apple up a flight of stairs however, the apple now has more potential energy then it had when it started. The apple’s energy has changed, so work has been done.
All the different forms of energy can be broken down into two categories: potential and kinetic energy.
My students have nicknamed potential energy the “could” energy. The battery “could” power the flashlight. The light “could” turn on. I “could” make a sound. That ball “could” fall off the wall. That candy bar “could” give me energy.
Potential energy is the energy that something has that can be released. For example, the battery has the potential energy to light the bulb of the flashlight if the flashlight is turned on and the energy is released from the battery. Your legs have the potential energy to make you hop up and down if you want to release that energy (like you do whenever it’s time to do science!). The fuel in a gas tank has the potential energy to make the car move.
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If you can’t purchase a mousetrap in your area, you’ll need to order one online.
in vietnam we don’t have mousetraps what will we do