Kids’ STEM Workshop: Catapults!

Kids’ STEM Workshop: Catapults!


This has been my most popular STEM program. We had 120 people attend, including about 60 parents/children who I had never seen in the library before!

To prep, I learned as much as I could about catapults. These websites were especially helpful:

Catapult Physics

History of Catapults

Build a Catapult

Little Bins for Little Hands: Catapults 

How to make a catapult for kids (YouTube video) This is very similar to the design that we made, however, we rubber handed a plastic spoon on the catapult where the person in the video is placing a penny, and we used pom-poms to avoid any injuries!

The type of catapult we built is a mangonel. Mangonels are simple machines and first class levers.

To begin the program, I brought all the kids into our programming room and had them sit on the floor. I asked them to tell me what they knew about catapults, and I answered questions or clarified their answers as they kept raising their hands to talk. After about 7 responses, I asked my guest speaker, a local professor of history at our local college to talk about the history of catapults. It is always fun to have a guest, and the parents gave me great comments afterwards that they learned something from his 5 minute history lesson.

Then, I had the kids holdup their right arm, and then grab their elbow with their left hand. I told them this would simulate their catapult. I then asked them to drawwwwwww (being very slow and dramatic) their right hand back as if it was being restricted by a rubber band or a rope. As it was drawing back, it was storing “potential energy”. And what happens to all that energy? It gets released! Then I asked the kids “fire” their catapult, which meant that their right hand reversed the motion of drawing back.

I had this image on my projector, so I did tell the kids all the parts of a catapult. Using their arm, I had them point to where each part would be. (I apologize. I forget the image that I found, although if I do find it, I will upload it ASAP!)

Now for the fun part! I told the kids it was now time to begin building catapults!

For our design you need:

  • 7 Popsicle sticks
  • 2 tongue depressors
  • Rubber bands (I bought a huge bag at the dollar store because they came in all sizes and thicknesses)
  • Plastic spoon
  • Pom-pom

I had all the supplies except for the pom-poms on the table. I also had an example of what a completed catapult looks like at each table. Then, even though there was tons of kids, I was about to talk to the group and give directions, “First you take seven Popsicle sticks and rubber band them together….” and go around to each table to help answer any questions.

When everyone was done making their catapult, I brought them back into our Storytime room (where we had begun) and gave them each one pom-pom. I then gave them 10 minutes to fire off and play. Then, I asked them to line up and fire in a row towards an empty wall (after reminding them that we never fire our catapult off at someone. All the kids listened and followed the rule!). We had about 15 minutes of lining up where I would count down, “Fire in 5, 4, 3, 2, 1!” and then the room would explode in pom-poms! The kids ran to grab their pom-pom when it flew off. Some of the kids lost their pom-pom, so I did give them another one.

This was the most popular STEM activity we have done so far, and it was incredibly fun! It was also very inexpensive, even though we had a large group.



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