Homemade Catapult

As a kid, I always loved creating engineering projects in school. One of my favorites was making a homemade catapult. Creating something to launch tiny projectiles at your siblings is every kids dream! This project is perfect for younger children, especially those in middle school. This project is a great way to teach about forces and how mass and acceleration can effect objects. These directions outline how to build your own catapult from items found at home, however students are encouraged to improve the design or use materials not listed.

Objective: Students will construct a catapult out of materials easily found at home

The following STEL's will be incorporated into the project through a hands-on design process where students construct their own catapult and are free to make changes as they see fit.

Core Disciplinary Standards:

• Core Concepts of Technology and Engineering
• Design in Technology and Engineering

• Integration of Knowledge, Technologies, and Practices

Practices:

• Systems thinking

• Creativity

• Making and Doing

• Critical Thinking

• Optimism

Contexts:

• Material Conversion and Processing
• Energy and Power
• The Built Environment

• Quarter Inch square wooden rods
• Tape or Glue
• Rubber Bands
• Scissors or Box Cutter
• Plastic Spoon

After gathering all required materials, the first step is to assemble the base of the catapult. Create a square with the wooden rods laying flat on the table. Attach the rods at each corner using tape or glue. Students can layer multiple rods on each side for added strength.

Our catapult is essential a lever and in order for it to work there must be a pivot point. To create this, students will cut 9 equal length pieces of wood. I chose to make mine 3 inches, but students can use any length that works. Once the 9 pieces are cut, attach them in the form of a square, creating a thicker wooden rod. This will act as our pivot point.

To attach the pivot point to the base, students will use two wooden rods going across the top of the base. The can determine how far forward or back on the base these pieces go. Once the pieces are attached, the pivot point will fit securely between them. Additional tape or glue around this area is recommended to help keep it in place.

In this step, students will connect the spoon to the base. Rest the spoon on the pivot point and wrap a rubber band around the end to secure it. Using multiple rubber bands will increase the force the spoon will rise with, however they will become increasingly difficult to put on the more you add.

Now that the catapult is complete, students may add their own supports or design elements to improve their catapults. Optimization ideas can include altering the length of the spoon, adding more rubber bands, or changing the height of the base. Once these additions are complete, students are free to test their catapults and launch projectiles across the room! Before testing, I recommend taping the base of the catapult to whatever surface it is sitting on. The catapults can be tested for distance, height, or accuracy during their final evaluations.