Simple Catapult

Learn how to make a simple catapult with just a few materials.

Supplies

• 6 jumbo popsicle sticks
• 5 rubber bands
• 1 plastic spoon
• Tape
• Puffball/wadded up scrap paper
• Something to launch your payload into or at

Step 1: Build the Base

Your catapult needs to have a strong, tall base. You need to use 4 of the popsicle sticks in a stack & band them together with a rubber band at each end.

Step 2: Make the Basket

The basket is the part of the catapult that your payload (or what you're going to launch) goes inside, it needs to be cupped to hold an object in place. The spoon will act as the basket and needs to be attached to a popsicle stick to make it longer. Place the cupped part of the spoon at the edge of the stick and tape it on with two pieces of tape, one near the top and one near the bottom so that it doesn't shift at all.

Step 3: Make the Spring

The spring gives the catapult it's energy. As you push down on the basket it builds up energy & becomes under tension as it stretches. When the basket is released the spring flies upward and released all of it's stored energy, that's how it flings something into the air. The spring on this catapult is a "v" shape with two sticks that are attached at one end with a rubber band. The top stick, with the basket, is the one that bends and pushes onto the rubber band to build up energy. Attach both sticks together with a rubber band at the empty end- the one where the spoon is not.

Step 4: Assemble the Catapult

Take the "v" part of your catapult and open it up so that you can slide the base into it. The two sides of the "v" will sit around the base. Slide it as close to the "v" rubber band as you can. Next, you need to get your base taller- the taller the base is, the more you can pull back the basket & gather energy for the launch. You can do this by turning the base 90 degrees so the sticks are sitting on their sides (last photo).

Step 5: Test the Catapult

You will need two hands to launch the catapult. One hand will hold down the base and the other hand will add the payload and pull back the basket to get ready for launch. Once the basket is pulled back all of the way, release the basket to send your payload flying! (Important: still hold onto the base of the catapult while you do this, otherwise the stored energy will just get translated into the whole catapult falling over instead of the basket rushing upwards.)

Experiment with your catapult. You can build a castle out of tubes or just empty containers to test your accuracy.

What happens if you pull the basket back only a little bit? What about if you use the table edge to help you pull the basket back a long way? What happens if your payload is very light weight? How about a heavier payload or even two objects as the payload?