Classroom Catapult

thingiverse

This is built with 8mm (5/16") wooden dowel sticks If you want to see more and how I create prints and 3D designs like this check out my YouTube channel. https://www.youtube.com/channel/UCSHUc93NXGwBacoIDDqPU2w Standards NGSS CCSS Overview and Background Functional and easy to assemble Catapult This project was created for my daughter to build a catapult for the Grade 6 D&T class. The design was done to be easy to assemble as per the picture provided. She can assemble this herself in about 10 minutes. The bucket will hold something around the size of an marshmallow. It is designed to be adjustable to find which angles will give the best trajectory and distance. Accuracy is consistent to within about 60cm at a distance of 10-15m. An adult may be needed to assist with initial assembly as depending on your printer, holes may need to be drilled out. By moving the 3 cross braces tension can be increased without adding more elastic bands. The one we built could easily take 4 thick elastics, but became hard to pull back and 2 worked fine. The top brace can be changed to adjust the release angle. Between 30 and 45 degrees. Lesson Plan and Activity The catapult can be assembled in class with no more difficulty than building a Lego structure. For teachers, I am happy to send you the FreeCAD source files if you want to make changes, as long as all changes are shared freely as per this license. Materials Needed Print all parts. You will need the 4 feet, left and right are different but as long as assembled the same will work. You will need 6 cross-brace pieces printed. You will need the 2 upper arm mounts, the bucket elastic holder, and pivot. The dowel stick needs to be: 4 x 220mm diagonal arms (Green) 2 x 350mm lower rods (Blue) 7 x 125mm foot cross-braces and lower elastic holder. (Brown) 3 x 100mm pivot and arms for release stop and elastic tensioner. (Red) 2 x 260mm for the arm (Orange)