Fab Lab Activity Plan: The Press Fit Catapult

Design and build a working catapult!

1: Stuff you need BEFORE the lesson:

• one computer per student.
• make sure every computer in the Fab Lab has OpenOffice.org Drawing and can send to the
• laser cutter
• make sure there is enough 1/8” plywood or cardboard for everyone to finish a house.
• have a method of showing the Intro and Safety videos: Projector / TV / Computer.

2: Opening Concepts:

• Show the Intro to the Fab Lab video. / Intro to activity.
• Explain what we will be doing today: Making a Press Fit Catapult
• Show Laser Cutter Rules and Safety Video.
• Explain press fit. Show how 2 flat pieces of cardboard can be fit together to make a 3D object.
• Ask the kids what the difference between 2D and 3D is.

3: Focus of the Lesson:

• The focus of this lesson is building a working catapult that is sturdy and can throw a ping pong ball.  

4: Teaching:

• Have everyone design a press fit corner: 2 pieces of cardboard that will press fit together.
• As people successfully create a press fit corner, ask them how they would use this same process to build a catapult.
• Have people who are finished with the press fit corner go on and design a catapult.

5: Wrap up:

• 1: Make sure everyone has cleaned up their area. Programs saved and closed, scrap cardboard thrown away.
• 2: Circle up: Ask various people questions: What should you think about when designing a catapult? Strength, force, rubber band tension, arm length, etc

If everyone finishes early, have additional discussion – get feedback. What can be improved?