Name of Activity



Kara Miranda


design, challenge, build catapult, launch, LEGO, not classroom tested, k-3, 4-6, 7-9, prototype, Engineering Design Process, lever, fulcrum, force, load


Simple Machines, LEGO Building

Grade Level

K, 1, 2, 3, 4, 5, 6, 7, 8, 9+


2 Hours Total

Brief Description

An design challenge in which students will design and build a catapult and see which design will launch an object the furthest. This activity can use either Lego or non-Lego pieces. *This activity is not classroom tested.*

Lesson Objectives:

To apply building techniques and knowledge about levers to an activity challenge.

Materials Needed:

Simple Machine or RCX kits

Example photos of catapults

Assortment of extra LEGO pieces, especially beams

Engineer’s Planning Sheet

Plastic spoons

Rubber bands

Tongue depressors



Ruler (yardstick or tape measure)

Preparation and Set Up:

Collect necessary materials

Photocopy worksheets Arrange students into groups of 2

Decide how you will distribute extra pieces and other materials

Write design requirements on the board

Find a section of the floor at least 15 feet long and put tape down on one side. Students will place their finished catapults on this line and launch the object from there, and the teacher can measure how far it has gone.

Necessary Background

Review three different classes of levers.

Vocabulary: Prototype Engineering Design Process


Lever (first, second, and third class)





  • Tell students that in this challenge they will be making a catapult. Explain to them what a catapult is, making sure to go into levers and its three different classes. A catapult can mean any machine that hurls a projectile. Students can use either Legos or non-Lego materials to create their catapult.
  • Show students different pictures and/or videos of catapults, explaining what they do and how they work. Explain the engineering design process.
  • Tell them the requirements for their catapults. Examples of requirements are:
  •       Must be six inches tall
  •       Must launch a ball at least 6 feet
  • Allow the class to brainstorm different ideas for their catapult design. Have them plan out and draw their design on the engineering planning sheet.

  • Distribute materials and have students start building.
    • After students finish building their catapults, have them place their catapult on the line and launch an object (preferably something that will not roll, perhaps a Lego piece). Measure how far the catapult launched the object.

  • After the students finish, review the activity with the class. Have them share their ideas, ask groups to explain what the hardest part of the challenge was, etc.
  • Extensions:

    Have students redesign their catapult to make it launch objects even further.

    Have a class-wide competition to see whose catapult launches the furthest.

    Reference 1

    Reference 2

    Reference 3

    2 comments on this post.
    1. Grace Reilly:

      We did this activity in our eighth grade classroom and it was a success. We used popsicle sticks, tape, rubber bands, and plastic spoons in building a catapult to launch ping-pong balls. The students did not have any requirements to meet in height of length of throw; we instead had a competition to see which group was able to launch their ball the farthest.

    2. Daniela Torres:

      This was the most exciting activity that we did with our 5th graders. It followed up greatly after the levers activity (also on the activity page). Seeing things fly really got our students hyped up. It is especially important to go around and pay attention to each group. Some groups don’t get it right away (either mixing up two lever classes or having an unsteady fulcrum) and frustration can come on quickly especially if they see their other class mates’ catapults whipping cotton balls around the room. It is important to slow down and remind them that the lever classes need to be followed carefully! I saw some neat designs including some that used elastic (rubber bands) energy to shoot their catapult.

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