STEM (Science, Technology, Engineering, and Math) Education challenges kids to use tools from various learning disciplines to gain new knowledge through critical thinking. The acorn catapult building lesson is an inquiry and solution-based challenge that is fun for kids, but it also provides the opportunity for kids to gain knowledge that can be carried beyond the classroom (or home) to solve problems encountered in the larger community.

Fall STEM Challenge for Kids:  Building an Acorn Catapult

Fall STEM Challenge for Kids: Building an Acorn Catapult

This lesson plan is designed for kids in 3rd-5th grades although it can be explored with younger children. If using the lesson plan with younger kids, be sure to explain how a catapult functions and experiment with potential designs together before inviting the kids to engineer a catapult independently.

Background Information for Parents and Teachers: Catapults were originally designed for use during wars and battles. With the rise in technology, advanced catapult engineering is used today to launch planes from aircraft carriers. Catapults use force to put a projectile in motion. The lesson plan below will use an acorn as the projectile. Students will be invited to construct a catapult using simple supplies that will propel the acorn through air to cover a distance.

STEM Skills Presented:
Science – kids will use skills within the scientific method (observing, communicating, comparing, organizing, and relating) while planning, constructing, and documenting learning in the catapult challenge. Kids will learn how force affects the motion of a projectile.
Technology – kids will view a catapult in action through the video below.
Engineering – kids will engineer a catapult using only the allowed supplies.
Math – kids will explore lines, angles, shapes, measurement, and mathematical relationships as they work to plan and engineer the catapult.

Engineering an Acorn Catapult

Information for Students: Ask the kids if they know what a catapult is? Show the kids the following video by Bill Nye (the Science Guy) on simple machines (including a catapult).

Discuss various kinds of catapults the kids have had experience with (such as a slingshot or shooting various projectiles from a simple spoon catapult). Use the following demonstration to show kids how a basic spoon catapult works to project an acorn into the air.

Materials needed:

  • One spoon
  • One small (cut piece) of Wikki Stix
  • One Acorn

Set the spoon on a table. Press a small piece of Wikki Stix to the top part of the spoon and then place the acorn on top of the Wikki Stix. Don’t press the acorn firmly to the Wikki Stix, but use just enough pressure to stabilize the acorn on the end of the spoon (see photo). Invite a student to use their hand on the opposite end of the spoon to project the acorn through the air. Discuss what happens to the acorn when more force is applied to the spoon. What happens when less force is applied to the spoon? The greater the force applied to the spoon, the farther and faster the projectile (acorn) will travel through air.

STEM Acorn Catapult Building Challenge

Invite the kids to engineer an acorn catapult from simple supplies. The building challenge can be completed individually, with a partner, or in teams.
Materials needed:

Kids must plan and build an acorn catapult using only the allowed supplies. Students DO NOT have to use all of the materials, but no additional supplies should be given. The time limit to plan and create is 25 minutes.

After the catapults are created, come together to test the catapults. Each student (or team) should measure and record the distance the acorn travels from the front of the catapult on each of two attempts. If the kids have access to digital technology, take videos of the catapults in action. Depending on the angles of the designed catapults, some of the acorns will travel primarily vertically or horizontally. Invite the kids to observe each of the catapult constructions and open discussion to consider why some designs were more successful than others.

Sample Catapult Construction Designs
The catapult construction (see right photo) was created by a 4th grade student. The initial design looked good, but upon execution, the catapult failed to launch the acorn as the wrapped end wasn’t secured well. The student improved the design by adding additional Wikki Stix to secure the catapult. With the improved design, the projectile (acorn) was successfully launched.

Another acorn catapult design (see photo on the right) was engineered by a 5th grade team. The team designed a base and mounted the arrow catapult construction to the top. By pressing downward on the center craft stick, the acorn was propelled through the air when the force was released.

Wrap-Up for the STEM Acorn Catapult Challenge
Download and print the Acorn Challenge Response Questions here. (download the pdf file of Acorn Challenge Responses here). Invite the kids to share the responses from the questionnaire and discuss improvements that could be make to basic catapult designs.

Planning and engineering an acorn catapult is a FUN way to incorporate STEM into daily learning! In providing opportunities for inquiry and solution-based learning at home or in the classroom, kids gain important skills to solve problems they do (and will) encounter in their everyday world.

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Simple Spoon Catapult

Simple Spoon Catapult

STEM Acorn Catapult Building Challenge Directions

Initial Catapult Design

Initial Catapult Design

Improved Acorn Catapult Design

Improved Catapult Design

STEM Challenge Acorn Catapult Design

STEM Challenge Acorn Catapult Design

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