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?