Rubber Band Powered Car

With this activity students will learn about physics and engineering.

Rubber Band Car

When you stretch a rubber band it stores elastic potential energy—the type of energy stored when a material is deformed. When you release it all, that stored energy is converted into kinetic (motion) energy, and as the rubber band is attached to an axle, it will start rotating.

    Materials:

    • 2 Ice cream Sticks
    • Rubber Band
    • 2 old Batteries or big Screws
    • Drinking Straw
    • Wooden Skewer
    • 8 Bottle Caps
    • Toothpick

    Tools:

    • Scissors
    • Hot Glue Gun
    • Drill

     Activity - Building a Rubber Band Powered Car

    1. Cut in half one of the ice cream sticks and glue it to the other two ice cream sticks leaving a stick distance from their tips. This will be the front of the car.
    2. Cut the straw in two pieces. The length of each piece should be an inch longer the half stick (width of the car).
    3. Using hot-glue, attach both pieces of straw to the front and rear of the car. They should be parallel to each other.
    4. Cut the rear straw in two pieces leaving a distance of one inch between them.
    5. Insert a wooden skewer through each straw. These will be your car’s axles.
    6. Make holes in 4 of the bottle caps. Make sure you make them right in the center of each cap.
    7. Use a scissor to make holes big enough for the skewers to fit in.
    8. Attach the bottle caps to the axles to form wheels, using hot-glue. Align the bottle caps so they are parallel to the body of the car.
    9. Make sure your car can roll smoothly. Put it down on a flat surface and give it a push.
    10. Add some weight to the car by attaching a battery to each of the ice cream sticks on the sides.
    11. Cut the toothpick in two small pieces (1/2 Inch)
    12. Glue one toothpick piece perpendicular to the half ice cream stick, and the other one right in the middle the rear axle on the exposed part of the wooden skewer.
    13. Hook a rubber band to the front toothpick, use hot-glue to fix it to that position.
    14. Hook the loose end to the rear toothpick, stick it as you did with the other end. When the skewer rotates, the rubber band should rotate with it.
    15. Wind up the axle that’s connected to the rubber band, put your car down, release the axle and have fun!!!

     

     

    Does the car move forward? How far does it go?

    If the rubber band didn’t unwind at all, wind it more tightly and try again. Make sure that the rubber band is attached securely enough to the skewer. If the wheels spun but the car didn’t move forward at all, there might not have been enough friction between the bottle caps and the ground, you can put a rubber band around each of the rear wheels to solve this issue.

    Make sure that both front and rear wheels are aligned to the body of the car.

     

      Analyze the results:

      What happens if students use a shorter or a longer rubber band? and if they twist the rubber band more?

      What effect does wheel size have on speed or efficiency?

      What effect does adding weight to your car have on efficiency?

       

      ISTE Standards

      4.c. Students develop, test and refine prototypes as part of a cyclical design process.

      4.d. Students demonstrate perseverance when working with open-ended problems.  

      5.c. Students break down problems into smaller parts, identify key information and propose solutions.

      5.d. Students understand and explore basic concepts related to automation, patterns and algorithmic thinking.

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