Trebuchet Project Description

Goal: Build a trebuchet.

This project is to build a classic trebuchet. (A trebuchet is a catapult that uses weights to launch the object as opposed to a compressed spring.) Before you will be allowed to start this project you need to:
  1. Get permission for a place to build and launch your trebuchet.
  2. Understand that I cannot help you fund your device.
  3. Realize that anytime a big lever is throwing things in the air there is a level of danger.
  4. Have the parental permission slip on moodle signed by one of your parents or guardians.  (Print out and have your parents sign the one that's on the moodle site.)

All steps of this process should be documented in you blog and pictures taken along the way and posted there as well.


Week 1:

  1. Research trebuchets on the internet. Record your findings in your notebook/blog.
  2. Design a model of your trebuchet that has a base no more than 1 square meter and is no more than 1.5 meters high.

Week 2:

  1. Come up with the question you want to ask and turn it in to the green folder.  (See Grading Rubric #4 for more information.)
  2. Test your model trebuchet. Things that you need to learn before you build your large trebuchet are:
    • Where is the best place to put your axle through your arm?
    • What is the best pin design for releasing your sling?
    • What is the best type of sling?
    • What is the best length of sling?
    • Any other questions that you may run into are fair game, test them!

Make sure to record how you tested the items above and what you found from your experiments. Include at least one picture of your model in your notebook/blog.

Weeks 3, 4 & 5:
Build your final trebuchet. Each time you work on it document it with digital pictures. Use a video camera or a digital camera in video mode to record two launches and get them them to Mr. Falk in one of your posts or an email.

Your final trebuchet must fit these parameters:

  • You must be able to safely and legally transport your trebuchet to school.
  • It must be designed to launch a tennis ball or a baseball.
  • On the day of the test you must tell Mr. Falk a 15m range that you can accurately land the ball in. For example, between 10 meters and 25 meters. He will choose 2 numbers inside that range. You must produce a graph and data to determine how much counterweight will launch your projectile to each of those distances. You will get three trials to hit each distance and your final product grade will take into account the percent error of your launches.  Your test with Mr. Falk will probably have to be done during lunch or after school.
  • Your trebuchet must be designed with redundant (2) safety systems that are always engages when someone is working in the path of the loaded trebuchet.  In other words, there should be two things that prevent your trebuchet from firing.