Summary
This engineering challenge is based on an internal competition designed by employees at Fluor Corporation.
Overview
Add a twist to a traditional "build a catapult" engineering project with this fun lesson plan based on the 2018 Engineering Challenge. Your students must build a device to launch a ball as far as possible—but they also have to build another device to catch it! With detailed rules and guidelines for a class-wide competition, this lesson is a great way to teach your students about the engineering design process.
Learning Objectives
- Design and build a ball-launching device and receiver based on specified criteria.
- Iteratively test, redesign, and modify the devices to improve their performance.
NGSS Alignment
This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:- MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
- MS-ETS1-4. 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.
Science & Engineering Practices | Disciplinary Core Ideas | Crosscutting Concepts | |||
Science & Engineering Practices | Engaging in Argument from Evidence.
Evaluate competing design solutions based on jointly developed and agreed-upon design criteria. |
Disciplinary Core Ideas | ETS1.B: Developing Possible Solutions.
A solution needs to be tested, and then modified on the basis of the test results, in order to improve it.
There are systematic processes for evaluating solutions with respect to how well they meet the criteria and constraints of a problem. ETS1.C: Optimizing the Design Solution. The iterative process of testing the most promising solutions and modifying what is proposed on the basis of the test results leads to greater refinement and ultimately to an optimal solution. |
Crosscutting Concepts | Structure and Function.
Structures can be designed to serve particular functions by taking into account properties of different materials, and how materials can be shaped and used. |
Materials

Each group will need the following materials:
- Corrugated cardboard base (max size 12"x12" or 30x30 cm)
- Large paper or plastic cups (16–18 oz, or about 450–500 mL)
- Wooden ruler or paint stirrer (12"/30 cm)
- Paper (printer/copier paper, not construction paper or cardstock; letter or A4 size)
- Wooden pencils (circular or hexagonal cross-section, approx. 7–8" or 18–20 cm length)
- Rubber bands (size 32, 3" long unstretched and 1/8" wide)
- Large paper clips (approx. 2" or 50 mm length)
- Roll of clear adhesive tape (Scotch® tape or equivalent, 1/2" or 3/4" width, max length 500")
- Sheet of aluminum foil (12"x12" or 30x30 cm), crumpled into a ball
- Scissors
- Tape measure (can be shared among several groups)
Background Information for Teachers
This section contains a quick review for teachers of the science and concepts covered in this lesson.In this lesson, your students will use readily available craft/office supplies to build a device that can launch a ball and a receiver to catch it (Figure 1). Detailed rules and scoring guidelines are provided so you can hold a class-wide competition and compare your class's scores to those submitted by other students around the world during the 2018 Engineering Challenge.

Two catapults are made from pencils, plastic cups, tape and a ruler and are pictured on the left of the image. Two receivers are made from paper, a plastic cup, tape and pencils pictured on the right.
Figure 1. Different designs for launching (left) and receiving (right) devices.
This challenge gives you the opportunity to explore some interesting topics in physics and engineering. Rather than explaining each topic in detail, this background section will give you a brief overview of each one, and you can decide which, if any, to address with your students. Explanations of each topic can be found in the Additional Background Links section.
- Simple machines: use the project to learn about simple machines like the lever and inclined plane. How can simple machines be combined to form a more complex machine that can launch a ball?
- Projectile motion is a classic topic in physics classes. How do the initial and launch angle of the ball affect its range?
- Energy is another classic physics topic. The ball needs kinetic energy, the energy of motion, to fly through the air. Where will that energy come from? It could come from elastic potential energy, the energy stored in a stretched material, like a rubber band. It could come from gravitational potential energy, the energy stored in an object that is raised up off the ground. Or, the energy could come from work that you do with your hand by exerting a force.
- Engineering design: you can also use this project to walk your students through the engineering design process. They probably will not build a perfect machine on their first try. Instead, they will need to iteratively test and redesign their launcher/receiver in order to improve the design.