How to make your own mini catapult

How can you build a catapult with pencils?

Safe­ty pre­cau­tions

Warn­ing! Only un­der adult su­per­vi­sion.


  • 5 pen­cils;
  • 1 plas­tic spoon;
  • 8 rub­ber bands;
  • sty­ro­foam ball.

Step-by-step in­struc­tions

Use rub­ber bands to fas­ten 3 pen­cils in the shape of a tri­an­gle. At­tach 2 more pen­cils to one side of the tri­an­gle as shown in the video. Make a small gap be­tween two of the pen­cils on the “for­ti­fied” side and pass a plas­tic spoon through it. Just at­tach the spoon with an­oth­er rub­ber band, and the cat­a­pult is ready!

Process de­scrip­tion

Cat­a­pults op­er­ate by ac­cu­mu­lat­ing po­ten­tial en­er­gy and con­vert­ing it into the ki­net­ic en­er­gy of a pro­jec­tile. When the spoon is pulled back­wards, the rub­ber band stretch­es and po­ten­tial en­er­gy is stored in it. When the spoon is re­leased, elas­tic force re­turns the band and spoon to their orig­i­nal states. Part of the stored en­er­gy is con­vert­ed into the ki­net­ic en­er­gy of the pro­jec­tile, launch­ing it into the air! The branch of sci­ence that stud­ies the launch, be­hav­ior, and im­pact of pro­jec­tiles is called bal­lis­tics.

Even more ed­u­ca­tion­al ex­per­i­ments await you in the MEL Chem­istry sub­scrip­tion!