Shop bestselling products! ➔

STEM Challenge: Build a Catapult


  • Easy, 100% Secure Checkout
  • Instant PDF or Zipped File Download
  • Create an account to download anytime
    from TeachingScience
secure checkout


Would you like your students to build a catapult? Students will learn about mangonels and trebuchets. Using the design process, students will build a catapult, test it, evaluate it according to the criteria and constraints, compare it with other design solutions, and improve their own design solutions. Students will learn about the mangonel, which uses tension to power the launch and the trebuchet, which uses a counterweight and gravity to launch the projectile. Students will love this engaging STEM activity, and they will love learning about these two mechanisms for launching a projectile.

Students will learn about planning an investigation and identifying independent, dependent, and control variables. Students will evaluate design solutions to see if they meet the criteria and constraints.

This unit includes:

  • A slide show on trebuchets and mangonels
  • Information on planning an investigation
  • Information on criteria and constraints
  • Strategic note-taking guide
  • Follow-up pages

This is a great, engaging engineering unit perfect for upper elementary or middle school science.

Teachers Love this Resource!

Alyssa ⭐️ ⭐️ ⭐️ ⭐️ ⭐️ Extremely Satisfied

My students enjoyed this project so much and learned from their errors! It was awesome to see their problem-solving skills increase throughout! Thank you.

Jennifer ⭐️ ⭐️ ⭐️ ⭐️ ⭐️ Extremely Satisfied I work with students with emotional and behavioral disabilities, and the more interactive I can make a lesson, the more successful it will be. Thanks so much for your hard work!

Standards Addressed:


Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.


Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.


Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved

NGSS MS-ETS1-1 Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions

NGSS MS-ETS1-2.Evaluate competing design solutions

using a systematic process to determine how well they meet the criteria and constraints of the problem.


Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.


Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.

Build a catapult

Build a catapult

Would you like to read more about this resource? Check out my blog post here!

SAVE$$ and buy this unit as part of a bundle!