So your science teacher gives you a class assignment to build a “mousetrap car,” which is to build and design a small vehicle that gets power from the snapping motion of a mousetrap so that the car can move as far as possible. If you want to outperform your classmates, you have to make your car as efficient as possible so that it will cover the furthest distance. With the right approach, you can draw detailed car designs to achieve maximum distance using only simple tools at home.
Step
Method 1 of 3: Optimizing Your Vehicle Wheels
Step 1. Use a large rear wheel
Large wheels have greater rotational inertia than small wheels. In practical terms, once the wheels start turning, they will have a harder time stopping. So the bigger wheels are perfect for distance contests - theoretically, they will accelerate more slowly than the smaller wheels, but spin longer and will cover longer distances. So, for maximum clearance, place the very large wheel on the steering axle (which is where the mousetrap is attached, which is usually the rear)
The front wheel doesn't really matter - it can be big or small. To make it look like a race car, you may want to put the big wheels on the back and the smaller ones on the front
Step 2. Use a thin and light wheel
Don't put weight on the wheels - unnecessary loads will definitely slow down the car or cause friction. In addition, wide wheels can have a negative effect on the towing of the car due to air resistance. Therefore, you are better off using the thinnest and lightest wheels for the car.
- Old CDs or DVDs work well enough for this purpose - big, thin and very light. In terms of compatibility, pipe plugs can be used to reduce the size of the hole in the center of the CD (to fit the axle).
- If you have vinyl records, you can use them too, although they may be too heavy for a very small mousetrap.
Step 3. Use a small rear axle
Assume your car is a car that relies on rear wheels. Every time the rear axle rotates, the rear wheel also rotates. If the rear axle is very thin, your mousetrap car will be able to move faster for the same distance than if the rear axle was wider. When the rear wheel rotates more, the distance traveled will also be further. So, it is quite wise if you make the axle from the thinnest material but still can withstand the weight of the frame and wheels.
Small dowels are a pretty good choice and are easy to get. If you have metal ingots, even better - when lubricated, metal bars usually don't rub very easily
Step 4. Create traction by adding edges to the wheel
If the wheel slips while the trap is snapping, energy will be wasted - the mousetrap works to make the wheel spin. However, due to skidding, your car does not reach the desired distance. Therefore, adding a friction-inducing material to the rear wheel will reduce the risk of slipping. In order not to put too much weight on, use as much induction material as necessary to give a little grip, and nothing more. These ingredients are:
- Electric adhesive
- Rubber
- The rubber balloon that has burst
- In addition, placing sandpaper under the wheels at the start of the motion will reduce the risk of slipping when the car starts to move (i.e. when the risk of slipping is frequent).
Method 2 of 3: Adjusting the Car's Frame
Step 1. Make the frame as light as possible
Most importantly, your car should be light. The less mass your car has, the better - every gram or milligram you can remove from your car's frame, will make your car go further and further. Try not to add any frame material other than that required by the existing mousetrap and axle. If you see a piece that isn't useful, try removing it, or if possible, punch a hole in it with a drill to reduce the weight. You can also use the lightest material for the vehicle frame. The following are suitable materials:
- Balsa wood
- Hard Plastic Sheet
- Thin and light metal plate (aluminum, zinc roofing material, etc.)
- Building toys (K'NEX, Lego, etc.)
Step 2. Make a long and small frame
Ideally, you want the car to have an aerodynamic shape - meaning, the car will have the least surface area on the part against which it is traveling. Like an arrow, longboat, plane or spear, a vehicle designed for maximum efficiency will always have a long, thin shape to minimize sliding against air resistance. For a mousetrap car, you'll need to build the car frame to be small (although it will be difficult to make a smaller frame than the mousetrap itself), as well as vertically slim.
Remember, in order to minimize sliding, you should try to make your car's profile as slim and small as possible. Try placing your car on the ground and looking at your car from the front to get a clearer view of the large looking parts of the car
Step 3. Use glue instead of nails wherever possible
If possible, apply glue to your car's design instead of using nails, glue sticks, or other heavy objects. For example, you only need to use a small amount of glue to glue the mousetrap to the frame. In general, glue will work just as well as nails, while nails will put unnecessary weight on it.
Another advantage of glue is that it usually doesn't affect the vehicle's wind resistance. Meanwhile, if the tip of the nail pops out of the car frame, this will cause a minor effect
Step 4. Always keep in mind the structural integrity of the car frame
The only limiting factor when it comes to building a lightweight and thin car frame is its fragility - if the frame is too light, the frame will be so brittle that a snap from a mousetrap will damage the car. Accuracy in balancing efficiency to achieve maximum distance with stabilizing the car will be quite difficult. However, don't be afraid to experiment. The mousetrap itself rarely breaks, so as long as you have plenty of frame material, you have the freedom to make mistakes.
If you are using a very fragile material such as balsa wood and are having trouble fitting the frame together, consider adding a stronger material such as metal or plastic to the underside of the side of the frame. By doing this, you have increased the structural strength of the car as well as minimized changes to its air resistance and weight
Method 3 of 3: Maximizing Car Power
Step 1. Give your mousetrap a long “arm” to increase its leverage
Most mousetrap cars work as follows: the mousetrap is “set up”, a rope tied to the trap is carefully wound on one of the axles of the wheel, and, when the device is snapped, the floating trap arm sends power to the axle to turning the wheels. Since the trap arm is quite short, a car that is not carefully constructed will pull on the rope too quickly and cause the wheels to slip and lose power. For a slower, firmer pull, try attaching a long iron to the arm that acts as a lever, and then try tying the end of the rope to this iron instead of tying it to the arm.
Use the right material as leverage. The lever must not bend at all due to the tension of the rope - when this happens, power is wasted. Many guides recommend sturdier balsa construction or balsa supports with added iron for a sturdy but lightweight lever
Step 2. Place the trap as far as possible
Assume that the trap will spin the rear wheel. You want the mousetrap to be located away from the frame so it doesn't touch the front wheels. The farther the distance between the trap and the wheel, the better - the longer the distance means you'll be able to roll more rope around the axle for a slower pull and more power.
Step 3. Ensure minimal friction on moving parts of the car
For maximum distance, you want to use almost 100% of your mousetrap's power. This means you have to reduce the “friction” on the surfaces of the cars sliding against each other. Use a gentle lubricant, such as WD 40, automotive grease or similar products to keep the contact points between the moving parts of the car lubricated so the car “runs” as smoothly as possible.
Many mousetrap car manufacturing manuals identify the axle as the main source of friction in mousetrap cars. To minimize axle friction, apply or spray a small amount of lubricant on each axle attached to the frame. Then, if possible, test the common ground by rolling the wheels back and forth
Step 4. Use the most powerful mousetrap
Most of the time, to make a mousetrap car, all students are required to use a mousetrap of the same size so that each car has the same amount of power. However, if allowed, use traps that have more power than regular traps! Larger traps, such as a sewer mousetrap, provide more power than a regular mousetrap. But this trap also requires a sturdier frame construction. Otherwise, this trap can destroy the car while slinging. You need to strengthen your car's frame and axle to match.
Keep in mind that sewer traps and other large rodent traps can break fingers. So, be careful, even when you are sure that the trap is already attached to the axle and will not snap easily
Tips
- If the rope is wound around the axle, it may be difficult for the car to move. The addition of a large link on the steering wheel can increase traction. In some pictures there is a rubber coil on the axle, which acts as a “gear” and reduces slipping of the rope.
- Use the longer lever to extend the mousetrap arm as far as possible. The end that traverses a longer distance will make it easier for the spool of rope on the wheel to work better. The antenna of a damaged radio can be used as leverage. Anything that is long, light and not very flexible can be used as leverage.
- Reduce friction on the axle by minimizing the support surface area in contact with the steering axle. Axle supports made of thin steel have less friction than holes drilled in wooden blocks.
- Reduce the shock by using a little sponge that acts like a cheese bait. This will reduce the car's jump when the lever arm snaps.
- Adjustment of axle lines and bearings is essential to reduce friction and improve performance.
- Reduce friction by applying Molykote® a powdered lubricant based on molybdenum disulfide to axles, wheels and mousetrap springs.
- Take the CD and axle to the hardware store if you are going to buy stoppers. It "may" help to get the size right the first time.
You can view student efforts on the Mouse Trap Car Challenge website.
- Increase friction by waxing the rope using light wax. By providing wax, the rope has a better pull on the axle.
- Increase friction where needed by using rubber or adhesive tape or apply adhesive around the axle where the rope is wound. The rope will rotate the axle and will not slip.
- Reduce the mass by using light sticks for the body parts of the mobi. Reducing mass will also reduce friction on the axle supports.
Things to Know
- Wheel to axle ratio: For distance, use a large wheel and a small axle. Imagine the rear wheel of a bicycle; Small gears and big wheels.
- Inertia: How much power does it take to run the car? Lighter cars require less power. Lower the mass of your vehicle for the best distance..
- Energy release rate: If energy is released slowly, power is used more efficiently, and the car will move further. One way to slow this release is to lengthen the lever arm. The longer arm travels further and leaves more room for the spool of rope around the axle. The car will move further, but more slowly.
- Friction: Minimize friction on the axle by minimizing the contact area. Brackets made of thin steel are used as an example. Initially, a hole is drilled in the block of wood used to hold the axle. Then, due to the larger surface area, the car uses energy to deal with friction instead of moving.
- pull: This is what is referred to as friction when used as an advantage. Friction should be maximized where it is needed (where the rope is wound around the axle and where the wheel meets the floor). Slipping ropes or wheels will waste power.
Warning
- There is a limit to the amount of power available; ie power per. The car that is exemplified is already an example that achieves almost maximum efficiency. If the levers were longer, or the wheels were bigger, the car “wouldn't move at all!” In this case, the released power can be “turned” by pushing the antenna inward (shortening the lever).
- Mouse traps are quite dangerous. You can break your finger. Ask an adult for help. You can get hurt and you can also break traps!
- Be careful when using tools, chopping wood or when using hazardous materials. You should always ask an adult for help when working.
