Easy catapult blueprints include ways to build the simple machines using household items such as pencils, clothes pins, Popsicle sticks and rubber bands. These designs demonstrate simple machines to curious children.Continue Reading
Using a Popsicle stick model, create a square base with four sticks secured at the corners with rubber bands. Make two v-shaped pieces and attach them to the inside corners of the base by wrapping bands at two ends on each side. Attach two crosspieces, the first one-quarter of the way up the front of the structure and the other at the top across the v-pieces. Finally, using one stick with a bottle cap glued to one end, attach the throwing arm to the center of the front crosspiece with the cap end threaded under the top piece of the structure. The rubber bands provide the torque for the catapult, while the top cross-member acts to stop the throwing arm, propelling objects forward.
Another design requires two pencils, a tissue box, rubber bands, a pipe cleaner and a bottle top. Remove the top from the tissue box and punch three holes in it; place two in the sides of the box, 2 inches from the end and one-quarter of the way down. Punch the third hole in center of the other end, 1/2 inch from the bottom. Insert a pencil crossways between the two side holes, and attach the second pencil with the cap glued to one end across the first with rubber bands, so that it is in the center of the box with room to swing freely at the bottom. Lastly, string a rubber band from the lower end of the throwing arm through the hole on the far end, and loop it around the pipe cleaner on the outside to create tension.Learn more about Building Materials