How to make an easy mousetrap car for science class that travels over 6 meters, complete with video instructions too.
I thought helping the twins with math would be my downfall, but you guys, 8th-grade science! Last week the kids came home with a project for their science classes. Their project (whether they wanted to do it or not) was to build a mousetrap car that could travel over 4 meters.
They drew up plans, modified them with the teacher’s help, and then last weekend we began constructing cars. They needed to do the work but I stood on the sidelines to help and guide them. We watched YouTube video after YouTube video together and read tutorials on Instructables. It was about 8 pm Sunday night when we finished our second car. They had to turn in their prototype the next morning for evaluation. The car would only spin in circles or flip over and couldn’t move in a straight line. We hoped the teacher would have some suggestions on how to improve it.
Before sharing these instructions you should know that I’m not a science teacher. I don’t pretend to play one online, I’m just a parent who was trying to help my kids with their project and this is what worked for us. If you have suggestions for readers on how to make the car even better I would love for you to share those in the comments. Leave links to your own mousetrap car projects that worked too because being parents is a team effort.
We left it for a day to get over our frustration before tackling the project again from scratch on Tuesday night. Flynn’s teacher had suggested using larger wheels; we’d initially tried using juice and milk bottle caps because they wanted the projects to use as many recycled items as possible. I headed to the store and splurged on blank CD’s and we started again.
Their new car with a new design and new materials traveled about 4 meters on the first try, and then 6 meters on the second (before crashing into the front door). I’ll share below what did and didn’t work for us.
How do you make a good mousetrap car?
I have loads of tips for you, but let’s start with what not to do.
What not to do
- Lighter isn’t better, your car will flip. You need more weight on it (more wood, washers, whatever works).
- Don’t go with a shorter car. A longer car with a longer lever will run further.
- Bottlecap wheels don’t work. I’m not sure what the reason was, but we tried it twice and even with electrical tape on them, it just wouldn’t go. That goes for milk jug wheels too.
Let’s break down some things that we changed when we made our new design and finally got a car that would run in a straight line over 6 meters.
- Wood rectangle (plywood is just fine)
- Popsicle sticks
- Wood dowel rods 1/4″ wide (either one long one you can cut or a couple of pre-cut ones)
- Hot glue
- Washers (make sure the hole fits over the wood dowel rod as snug as possible)
- Cord or rope
- Eye screw
- MORE HOT GLUE – I can’t stress this enough
- Straws – I’ve posted a link at the bottom to what we used that fit perfectly over the wood dowel rod giving it enough space to rotate inside
- Electrical tape
- CD’s or DVD’s
Instructions to make a mousetrap car
I’ve provided a video below so you can see how it worked, but here are images of the top and bottom of the car so that you can see how to assemble it.
One of the issues we faced was getting the axle (the wood dowel on the back wheels) to rotate. The second car we made we had seen a tutorial for a small juice box straw that had a wood skewer running through it. It just didn’t feel strong enough though and when the teacher suggested bigger wheels I knew we had to go bigger everything. This meant finding a larger straw that would fit a dowel rod through it. In the middle of our dining table I spotted it. I keep a rotating tray in the center of our dining table with things such as napkins, honey sticks, salt and pepper, and Milk Magic straws. Drink up kids, we’re using those straws.
These are the products we used (they are Amazon affiliate links, it doesn’t cost you any more to buy through them though).
This is the video I made so that you can see it running. I had to cut the video short because it was going to run into me, but it ran over 6 meters.
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