A brief explanation of the projects:
The science behind the catapult is based on energy transfers. The elastic potential energy stored in the rubber band transfers into kinetic energy to the arm which in its turn transfers energy into the payload. The more elastic potential energy the rubber band stores, by pulling the rubber band back as far as possible, the farther the payload and ammunition travels.
By Pablo R
" What I really like about catapults is that people think of them as old, forgotten weapons when really they were a very important revolutionary advance and dramatically reduced the high mortality of the offenders.
What is a catapult: A catapult is a ballistic device. They were, and still are, fantastic war machines. Mainly used during the Middle Ages, they allow ammunition (projectiles) to be launched without any type of propellants, like gunpowder, and to hit a target such as castle walls during attacks and sieges.
How did I do it?: So first, to make the catapult we needed a few tools and materials including popsicles elastic bands and hot glue. We did not really need hot glue but it was a good addition to make the structure more stable. You would also need some sort of open container to be able to hold the projectile while it wasn’t being fired."
"Over the half-term for Science we had to make a catapult and this was our result. I made it out of wooden sticks that are stuck together by silicon glue."
"This is a catapult which I made for a Science project, during the half-term holiday. I made it using sticks, rubber bands and glue. Firstly I made a rectangle platform with the sticks. After, I made two triangles and I stuck them to each long side of the rectangle, then I added half a stick across the two triangles to rest the arm on. After, I finished the body of the catapult, I then started to make the arm; a long thin rectangle. Then I made a small box in which you will place the object (ammunition) to fire. Finally I stuck the box to the long rectangle, joined the arm to the body of the catapult with rubber bands, and at the end of the arm, I added rubber bands.
To use it you have to pull the arm down from the box, and when you are ready, release!"