Catapult design is a great way to engage kids in catapults (because CATAPULTS!) and also teach the engineering and design process. We created our catapults in the winter to toss ‘snowballs’ aka cotton balls around. This can be a great activity to pair with the creation of fake snow too.

You won’t need much in materials for this kids catapult project. By keeping the supply list simple, we are actually making the project very difficult. It will challenge kids to think outside of the box when they have to make a catapult with nothing but wood sticks and rubber bands (or maybe you allow them hot glue).

Project Ingredients:

• Wood craft sticks (Dollar Store is a great place to get these)
• Rubber bands (again, the Dollar Store is the place to go for these)

What is a catapult?

The catapult is a device, invented in medieval times, used to launch heavy objects. The catapult uses the accumulation of tension to create the force of launch. That tension can be stored in the bending of our wood sticks, the stretching of rubber bands, or some combination of both.

Catapult design for kids

Here are a few things to think about while designing your catapult.

What is the strongest base structure?

If we want to be able to fling our snowballs as far as possible, we will need to be able to accumulate a lot of tension in the system just before launch. This, however, can pose a problem. If your system accumulates too much tension it might not put all that energy into launching your snowball, but instead into breaking your catapult.

When designing your catapult you will want to think about how you can create a strong base structure. Does that mean stacking lots of wood sticks together? Arranging them in a particular three-dimensional shape? bracing the structure in specific ways? These are all things to think about and plan for while creating your catapult.

What will make your catapult fling?

The catapult has to be able to store tension and release it when we want to launch our snowball. But where will you accumulate that tension? There are lots of ways to do this, and no right answer, so again, experimenting with different types is the best way to optimize. You can make it so the rubber band stretches linearly (like when you fire a rubber band gun) and that release of tension fires your snowball. You can also make it so the rubber band stores energy torsionally (in a rotational manner) so that the fling is like a pitchers arm flinging the snowball in an arc. You can make it so the force comes from pushing down on a see-saw like piece of wood. Again, there are a lot of options here, and a lot of ways to play with your catapult design.

What will make your catapult cool?

Technically this is an unnecessary step in catapult design, but let’s be honest, who doesn’t want a cool catapult? Maybe you need laser wires, serious spikes, gruesome eyeballs, an area to stockpile snowballs… The list can go on and on. What will make your catapult design stand apart from the rest?