Slingshot Cars

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Introduction: Slingshot Cars

About: I'm a writer, maker, and educator who's on a mission to better the world through hands-on engineering projects. Check out my work: www.stem-inventions.com/

The slingshot car is an excellent introductory project to illustrate how potential energy is converted into kinetic energy, and the importance of low friction. Just be sure to watch your feet as cars go racing across the floor!

You can find the lesson plan, 1-page project sheet, and more project ideas at STEM-Inventions.com

Project Goal: Students build cars that are rapidly propelled across the floor at least 10 feet.

Design Variables

  • Axle width
  • Number of wheels

Key Concepts

  • Wheel Alignment means all the wheels all point in one direction
  • Energy transformation is when one kind of energy turns into a different form

Prep: Bend paperclips into hooks (1 per student)

Safety: Launch cars only horizontally across the floor. Designate a launching area and direction when students begin to test.

Step 1: Materials

Please message me to report broken links. All of these materials are used in my other Instructables for kids, so your purchases can be used across multiple projects.

8 Craft sticks
4 Wheels
2 Straws
1/8" dowels
1 rubber band
Masking Tape

Hot glue with safety nozzle
Craft cubes (for extra modifications)
Plastic cups (for stackable crash targets)

Step 2: The Basic Frame

The frame can be just about any shape and size. I use a rectangular frame for my example because it has about the same proportions as a real car and it's easy to build.

Step 3: Adding Wheels

Create the wheels by putting a dowel into a straw, then put the plastic wheels onto the ends of the dowel. Wrap a small piece of tape around the ends of the dowel to prevent the wheels from falling off.

Step 4: Attach the Rubber Band

Use 2-3 layers of masking tape to attach a rubber band onto one end of the frame. This step completes the essential car frame!

Step 5: Optional: Customize the Car

It's fun to make the car personalized. Use craft cubes and sticks to give it a cool profile.

Step 6: Set Up the Launcher

Tape a pencil to the floor. Make sure to layer and crosshatch the tape to keep the pencil secure to the floor.

Step 7: Launching the Cars

  1. Place the car on a smooth, flat surface with the rubber band pointing in the direction that the car will be traveling.
  2. Hook the rubber band onto the pencil eraser.
  3. Pinch the back center of the car frame, pull back, and release!

Step 8: Safety, Tips and Troubleshooting

  • Don't allow your students to fling the cars directly at each other.
  • Some students will want to crash their cars into things. Bring plastic cups and stack them into pyramids to make some dramatic and appealing targets.
  • If the car is spinning out, make sure the wheels can spin freely, and that the wheels are aligned.

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    6 Discussions

    0
    ElenaL6
    ElenaL6

    4 years ago

    We made this project, but cannot get the cars the ride on the floor... The shoot out, turn over, fly off, but do not drive. Would you please offer us an advice? Thank you.

    0
    LanceMakes
    LanceMakes

    Reply 4 years ago

    Hi - Make sure you're following the launching technique correctly. It's important that the rubber band is parallel with the floor when you're stretching it out.

    If you launch it with too much energy, it will always skid out of control. Try using small amounts of energy at first, then increase it until you've found the right balance.

    It's also important to use long rubber bands and wide-set wheels. Good luck!

    0
    T0BY
    T0BY

    5 years ago

    Great project idea!

    0
    ESOL_Teacher
    ESOL_Teacher

    5 years ago

    I cannot wait to try this with a group of Beginning English Learners!