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Trebuchet by Angus and Jonathon

We're Angus and Jonathon, and we're into really old-school stuff: medieval history! When we're not building castles, playing joust, or reading about knights, we're engineering stuff. Our most recent invention is called a trebuchet, a slingshot-like tool dating back to medieval days that is useful for transporting materials (translation: flinging stuff) long distances. We want to throw out this DragonflyTV question: What trebuchet design will allow us to throw things the farthest?

What did we do?
Working with Lansing, Michigan's Impression 5 Science Center, we engineered five trebuchet models. We were specifically trying to discover which combination of sling length and counterweight throws the farthest.

What did we find out?
We learned that the model with the medium sling length and the heaviest counterweight worked the best for transporting materials (translation: flinging stuff!) long distances. So we built a functional, life-sized trebuchet based on this best model design, and used it for the very important tasks of, well, hurling piñatas, water balloons, and giant cans of pudding down a football field!

What can you do?
  • Do a quick investigation of how to fling things, using a meter stick. Hold the meterstick onto a table top, with 10 centimeters over the edge. Set a penny on the end, and try to give it a "twang". How far does the penny fly? Repeat this, with 15 cm of the stick hanging over the edge, then with 20 cm, 25 cm, etc. Do the pennies fly higher as you extend more of the stick off the edge of the table? Do they fly farther?
  • Find a water balloon slingshot at a toy store, and do an investigation of things that hurl! Make all the water balloons the same size (as much as possible), and try different investigations, How far do the balloons fly as you change the angle of launch? You can also use a stopwatch to record time of flight with different angles. Challenge yourself to come up with a launch strategy to make a balloon hit a certain target.
  • Use this technology investigation as a science fair project idea for your elementary or middle school science fair! Then tell us about it!
more resources
Go to the DFTV Boards, and tell us about your science investigation.
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