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Building a KEVA Trebuchet

Over the holidays, Science World volunteer, Steve Ellis received a KEVA Trebuchet as a gift from Science World volunteer, Madeleine Butschler. Once they were done building the project, they did something different with it—they decided to donate the trebuchet to our KEVA Gallery collection. They also shared their detailed project notes, complete with results and ideas for cool experiments!

A trebuchet is a medieval device that was used to besiege a castle or assault an enemy army in war. It’s a marvelous and relatively simple machine that relies on gravity to make it work.

It's essentially a lever—a beam that can pivot around a fulcrum.  On the longer end of the beam, there's a sling which holds the projectile (whatever you want to throw). A heavy weight is attached to the shorter end of the beam.  To load the trebuchet, you pull down the longer end and hold it in place with a trigger. As the longer end is going down, the weight on the shorter end is lifted up. When you release the trigger, the weight drops and the long end of the beam swings upward, pulling the sling after it and launching the projectile toward the target.

An early form of trebuchet may have first appeared in the fourth century. The trebuchet was a prominent weapon throughout Europe, the Middle East and Asia until the 1500s. In recent history, the trebuchet was replaced with more sophisticated weaponry. However, the design is so simple and efficient that it’s been known to show up in a modern battle or two.

Check out some tips, tricks and experiments for the KEVA Trebuchet from Madeleine and Steve.


Have you visited our KEVA Gallery recently? Learn more about KEVA by reading about what it's like being our KEVA Gallery Curator.