About Scitech
Scitech is a not-for-profit organisation proudly supported by the Western Australian Government through the Department of Jobs, Tourism, Science and Innovation
How does it work?
Catapults work by converting energy from one type to another and transferring this from object to object.
This simple pom-pom catapult uses elastic potential energy stored in a wooden stick as you bend it. When you let go, this stored energy is released, converted into kinetic energy. The kinetic energy is transferred to the missile (the launched pom-pom!), which then flies through the air.
What you’ll need
- 6 or more pop-sticks
- 5 or more elastic bands
- 1 plastic spoon
- A pom-pom or ball of paper.
What you’ll do
- Stack 4 or more pop-sticks together and join them with an elastic band at each end.
- Take 2 more pop-sticks and join them together at one end, creating a ‘V’ shape.
- Place the 2 pop-sticks on top of the 4 stacked pop-sticks, like a plus sign.
- Strengthen the centre of your catapult using an elastic band to hold the pop-sticks in place.
- Attach a spoon to the top pop-stick to hold your pom-pom projectile.
- Place the pom-pom in the spoon, pull it back, and watch it fly!
Refine your design
Now it’s time to tinker and try to refine the design.
- Try moving the 4 pop-sticks closer to the end.
- Add more pop-sticks to the stack of 4.
- Make the pop-stick holding the spoon longer.
- What works best? What happened to the pompom? Did it fly? Did it go high or low? Where did it land?
- You can also set up targets such as a group of cups to test accuracy as well as distance.
For an extra challenge
- What do you expect will happen when you push the projectile farther down? Will this make it fly higher, farther, both? Will it take the same path and go faster?
- Does your pom-pom land farther or nearer when you push a lot compared to a little?
- In which scenario did you have to exert more effort/work? When you pushed a little or a lot?
- Did you get similar results with each variation? Is what you observed what you expected?
Can you explain why? - How did your changes affect the pom-pom’s flight path?
