Hello, engineers! Before the pandemic, I had a chance to compete in a Guinness World Records attempt at the fastest catapult build and launch. And while my 37-second build was impressive, I definitely did not win. But I did have a ton of fun and was reminded how easy catapults are to build, and how great they are at showcasing the process engineers go through when designing something. Today, you can step into the shoes of an engineer to create your own simple catapult.
Did you know: Catapults were first invented roughly 2,500 years ago. They are relatively simple, yet very effective machines. They were created to launch projectiles, like large boulders, stones or spears more than 300 feet! Catapults work by suddenly releasing stored up potential energy to propel projectiles, so these projectiles could tear down walls. Don’t worry — we’ll only be flinging soft pom poms.
Supplies
- Popsicle sticks (about 10)
- Rubber bands (3 or more)
- Pom poms or cotton balls
- Plastic spoon (Or, try hot-gluing a bottle cap to a popsicle stick instead)
- Paper and pencil to record data
- Measuring tape
- Optional: markers and stickers for decorating your catapult
Safety Note: Never put anything hard in your catapult, and always aim your projectiles away from you and others. Your adults will also appreciate it if you try not to aim at breakable things.
Build Your Catapult
- Decorate your popsicle sticks first, if you want to.
- Stack up one or two popsicle sticks, then stack the spoon on top.
- Wrap a rubber band around the end of the stack where the spoon handle is to secure them together.
- Stack a few popsicle sticks together and wrap rubber bands around each end to secure them together.
- Place stacked popsicle sticks in between the spoon and the sticks held together with a rubber band at one end. You may have to wedge it in there!
- Place a pom pom in your spoon and test your catapult by pulling back on the spoon.
- How far did your pom pom (projectile) go?
- Measure the distance and record your data!
What’s Happening?
A catapult works by storing up potential energy when pulling it back to launch. This energy is transferred to the projectile, propelling it out of the catapult and toward the desired target area. A big part of the engineering design process is to both test and improve your design: How many popsicle sticks did you stack and wedge under the spoon? Try adjusting the number of sticks — does anything change? What happens to the pom pom when launched with your new design? What happens if you extend the length of the spoon by rubber banding a popsicle stick to the handle? Which one goes farther? Why do you think that is? What other improvements could you make and test with your design? Remember to record your data!
Want to Learn More?
Want more opportunities to build, test, and tinker? Come visit the Build It exhibit at Arizona Science Center on display now through January 2022. This exhibit allows visitors to activate their inner engineer and practice principles of innovating, designing and constructing. Check it out! For tickets and more information, visit azscience.org
