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Activity (Hands-On)Grades 7 - 9

Trebuchet Design & Build Challenge

A drawing of a wooden trebuchet as it launches its payload.A diagram of how a trebuchet launches its payload

In this activity, students explore how trebuchets were used during the Middle Ages to launch projectiles over or through castle walls as well as how they are used today in events such as Punkin’ Chunkin’. Students work as teams of engineers and research how to design and build their own trebuchets from scratch while following a select number of constraints. They test their trebuchets, evaluate their results through several quantitative analyses, and present their results and design process to the class.

The trebuchet is a classic example of ancient engineering design. Not only is it a compound machine (a device that uses a number of simple machines), it relies on one primary simple machine, the lever, to launch a projectile. Trebuchets were engineered due to an enhanced understanding of gravity, potential energy, and acceleration—each of which is a key concept in engineering today. This design project allows students to use the engineering design process to research, design, and build a trebuchet.  They also rely on their knowledge of algebra and physics to explain their results.

A circular image of the seven steps in the engineering design process, including: ask: identify the need and constraints; research: the problem; imagine: develop possible solutions; plan: select a promising solution; create: build a prototype; test: and evaluate prototype; improve: redesign as needed.The steps of the engineering design process.

After this activity, students should be able to:

  • Design and build a trebuchet with constraints.
  • Test their designs and analyze the results of their tests.
  • Communicate their design process and results.
  • Create instructions on replicating their design.

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