Basic desktop catapult design. Customize just about anything on it and see what combination of parameters sends a projectile flying the farthest. Play with the length and thickness of the arm, along with its angle from the ground and the diameter of the bucket. Adjust where the arm will strike the crossbar. Also customize the dimensions of the base, adding supports on the front if using a high armAngle so it doesn't flip over. Make predictions with your class, print what they think will work best, then give it a go!

Note, I don't have a printer and can't do any actual testing so I apologize if this doesn't function quite as planned.

Objectives:
Give students a visual demonstration of projection and how launch angle, spring tension, and having something like the crossbar all effect the horizontal and vertical distance a projectile will cover.

Audiences:
All ages could enjoy this project. It could be a toy or simple, interesting demonstration for younger children or it could be used as an education demo for early high school physics challenges.

Preparation:
Students should have a decent understanding of grade 9 physics regarding energy transfer and projectile trajectory.

Steps:
You have two main options:
-print a couple different designs, show them to your class and let them guess how each will perform, or
-put students in groups, show them the customizer, and let them do some calculations and then choose the parameters they think will give the best results, print, then test

Results:
You could keep it simple and have students choose the parameters that will cause a projectile the farthest, or you could make it a little more complex and add some obstacles. Perhaps have them shoot from under a desk so they can't shoot too high, but also stand up a textbook on the floor so they can't shoot too low either. Another option would be making paper targets and giving students marbles for ammunition.