How Does a Trebuchet Work?

Video Transcript

"Hello, I'm Steve Jones, and I'm going to tell you a little bit about the Trebuchet. Now, this device was known even as far back as the Romans, and was the basic piece of siege artillery that was used at the time. The only purpose of the machine was to throw large objects--heavy pieces of rock to break down walls. And this was usually during sieges. That was the only function it had. The device itself was a heavy frame, and it was a very heavy frame, on which was poised a beam, a long arm, and a short arm of the beam, with a pivot here at the top. It was counterbalanced by this huge counterweight which could be several tons if necessary, and at the other end of the beam was a sling in which the projectile was placed. This is the projectile--as I say, this could be a large rock or some other object. The object operates by releasing the beam--the beam would be attached to the bottom, and then it would be released, and gravity, acting on the counterweight, pulls the counterweight downwards. And as you can see, this is a short distance, this a long distance, so the speed of this is amplified four times or so, and it whips around with the sling pulling the projectile. Obviously, there is a guide shoot here to make sure that the projectile doesn't come out of the sling too soon. As it accelerates, it is then swung in an arc and when it reaches high on the arc, the sling will become slack, then the projectile continues on its own path to the target. This can be adjusted so that the object can be released at different points along this arc. If it is released too soon, it will simply go straight up in the air and come back down on the object itself. If it is released a little bit later, it will have quite a high trajectory and will travel much further. If your--if you want to batter something which is fairly close, then you make it come out much later. But this is adjustable on the trebuchet itself. So this object was the main siege weapon over thousands of years--certainly two thousand years, certainly from the Romans onwards. And it can be seen in pictures of battles and sieges throughout--certainly throughout the Middle Ages as well."