How to Build a Strong Catapult: STEM Learning Activity

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Have you always wanted to learn how to build a catapult? Yes? I thought so… me, too. Making this homemade catapult is really quite easy and is a fun activity for kids of all ages! I can’t wait to show you. DIY Catapults are a classic STEM activity.  But, this one way cooler than those little popsicle stick catapults you have probably seen before! This project is great for older kids and younger kids alike.

A building a catapult is an awesome STEM activity because kids are learning so many things!

Catapult Learning Connections:

Teaching kids how catapults work along with just how to build it is important to make the STEM connections in this activity.

Engineering: You are learning how to build a catapult that will stay together and work well.

Science: This is awesome for a physics lesson on Newton’s laws of motion. You can teach about kinetic energy (energy of motion) and potential energy (stored energy) with the process of pulling back and releasing. When you pull back the cup you are creating potential energy. When the energy is released and you launch a projectile, it is now kinetic energy.

Teach force and velocity. You could change the weight and size of the ball you use to catapult and test to see if it goes a different distance or height.

History: Catapults have been around for thousands of years! There is so much cool history you could delve into here. This type of catapult we are making is closest to a Ballista catapult.

I promise you when I say this is an easy project! With just looking at a picture, I’d bet you most kids (upper elementary on up) could easily make this. (No glue guns required for this one!)

Supplies to Build a Catapult:

6 wooden dowels (ours are 3 ft long) You can get these at Walmart, the craft store or the hardware store.

9 large rubberbands or elastics

Small plastic or paper cup

Single hole punch

Scissors

Small balls, balls of paper, pom poms, or jumbo marshmallows to launch

Let’s start with building the catapult frame, or the base of the catapult. Use three of the wooden dowels and make them into a triangle by attaching the corners with rubber bands.

Then the next three dowels you also attach as a triangle, but standing up like a tepee or a pyramid. Add one at a time going upward from each corner of the first triangle. Then connect them with a rubber band in the center on top. IT needs to have a lot of tension.

Next, take your plastic cup and punch three holes in it- evenly spaced around the top of the cup.

Cut three rubber bands in half and tie them through the holes in the cup. The other ends of the rubber bands need to be tied to the top part of the catapult, and two bottom corners. You’ll need some bigger rubber bands to make this work. If your rubber bands are not long enough (mine were not) tie on three more runner bands to the ends so they can stretch all of the way down the dowels. The cup and rubber bands together create a type of throwing arm.

Shoot the Catapult!

Put a small ball, such as a ping pong ball, into the cup, pull back and let it fly!!! You have now finished building a catapult. Everyone will be impressed. (And you don’t have to tell them how easy it was!) It is seriously so much fun!

We built this catapult years ago and I figured it was due for some updated pictures, but I had to retain a piece of history on the site by keeping this good old original picture! This older picture was with my oldest son. I am now repeating it with my third child. He is SO excited about it and spent forever shooting balls across the yard! I love repeating favorite projects again with my younger kids.

Check out my SCIENCE ART Book!

Looking for more cool STEM engineering projects?  Check out a few of these:

Bubble Blower Machine
Make Paper Hold Up Books
Engineering Building Toys with PVC Pipes 

Here are a couple of other cool catapult projects from some blogging friends:

Popsicle Stick Catapult from Frugal Fun for Boys & Girls
Ice Cream Scoop Catapult from JDaniel4’s Mom
Pencil Catapult from Little Bins for Little Hands

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