A group of UT students from the American Society of Mechanical Engineers and Pi Tau Sigma visited the Museum to show kids how to make their own catapults out of popsicle sticks, rubber bands, and a bottle cap!

Want to build your own catapult and experiment with tension? Click here to download the instructions in a PDF file.

When you press the arm of the catapult down with your finger and hold it in place, you’re stretching the rubber bands. The stretching creates a force called tension. Then, when you let go, all that tension is released—causing the arm of the catapult to fly forward!

Another example of tension is when you play tug-of-war. When the two teams are pulling on the rope in opposite directions, the stretching causes a lot of tension in the rope. That’s why if one team lets go, the tension released has enough force to make the other team stumble!

How far does a ping pong ball fly if you press the catapult arm all the way down? How far does it fly if you press the arm down only a little bit?