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Machines That Perform Tasks

The Catapult

A Science Project in Physics


Problem: Design and build a size/mass restricted catapult that can propel a large egg over a one-meter tall wall being placed one and one-half meters from the wall.

Objective: To perform a task using simple machine principles in the construction of a catapult.

Project Restrictions

Catapult dimensions / Restrictions

    1. Mass of your catapult may not exceed more than 1 kilogram (2.206 lbs.)
    2. Height of the catapult may not exceed 0.5 meter in any direction
    3. Your catapult must be based on a sling shot or third class lever mechanism

Project Requirements

Group Work and Project Contract

The catapult project will be done within groups of 2 or 3 students, depending on how many students are in each science class. Students will choose their partner and both the student and parents must sign a "contract" to allow the group to proceed.


Each individual will be required to keep an accurate, up to date journal during the duration of this project. Each journal entry must be dated. The following Journal entries are required.

bulletDrawings of each step and redesign of your catapult
bulletResearch notes on your project
bulletData collection tables
bulletThoughts and ideas detailing how you change your design or the collection of new data.
bulletMaterials list
bulletPictures of each step in your design process


Web Page / Power Point Presentation

During the course of this project you must keep accurate data, notes and pictures/drawings that you can then use to build a web page or Power Point Presentation. Place your web page or Power Point Presentation onto a floppy disk.

Project Contest

A contest will be conducted on an assigned date to demonstrate your groupís ability to solve all the design problems associated with this project. A preliminary testing date will be set to practice your catapults abilities and a final testing date will be set to determine your final project grade. The contest will be run twice, a practice day and a final day. Both scores will be added together to determine the class ranking.

Scoring of Contest

bulletPropel an egg over a one meter wall safely (20 points)
bulletFor each centimeter that the egg travels past the wall, the group will score one additional point.
bulletIf your egg lands safely without breaking, a bonus of 50 points will be awarded to your team.
bulletWinning and runner-up teams in each class will be rewarded with a pizza party. Losing teams in each class will be required to clean up the mess from the fractured poultry bombs.

Grading of Project

The Catapult project will be graded with a scoring rubric which is attached. Points earned in the contest will be utilized as part of the studentís final grade as will the journal, and class participation.

Preliminary Contest Day (indoors using golf balls):

Final Project Testing Date:

Developed and designed by Dave Crosby 11/14/00