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Minor Versionm

by Suhail Ahanger


Using the energy stored in a rubber band, we make a self-propelled bottle boat using ice-cream sticks as the propeller. This shows how ducks swim and how ships propel themselves.

Video Overview

    • Exercise caution when using paper cutter/scissor

  1. Measure the spoke length and mark the midpoints of both the spokes.
    • Measure the spoke length and mark the midpoints of both the spokes.

    • Attach spokes on to the bottle using small size rubber bands.

    • Insert spokes at diametrically opposite ends up to the halfway mark, and keep the bent end towards the cap

    • Make the spokes hold firmly on to the bottle by applying adhesive tape

    • Use glue where ever tape is used to have stronger adhesion.

    • Cut the ice cream stick such that its length is slightly more than the gap between the spokes.

    • Make notches at both ends of the ice cream stick (to fit into the spokes) and stick it to the bottom of the bottle with tape.

    • Use Glue for better adhesion wherever sticking of tape is required

    • Secure a medium or large sized rubber band near the end of the spokes

    • Take 2 ice-cream sticks and measure them such that their length is the diameter of the bottom of the bottle + 2cm, and cut them to that size

    • This is the length of your propeller

    • Glue/tape the sticks together, laterally, to make your propeller.

    • Attach the propeller near the middle of the rubber band to avoid tilting during propulsion.

    • Now twist the rubber band multiple times with the propeller and release it after placing it in water.

    • Water is getting inside the bottle: Check if the bottle cap is tightened properly and if any hole is present along the floating side.

    • Boat not balanced while floating: Check that the spokes are at diametrically opposite ends. Also ensure the propeller is exactly in the middle of the rubber band.

    • Twist the propeller rubber band in both directions and observe the direction of motion.

    • Use a bottle with a sharp bend (90 degrees) at the front. Does it turn on its own? Compare this with a smooth curvature at the front end of boats or big ships.

    • How does twisting the rubber band translate to the forward propulsion of the bottle?

    • Try shifting the spokes towards the propeller and see how that affects the motion/balance. What happens if it is heavy near the cap of the bottle or near the propeller end of the bottle?

    • Use thread instead of rubber band to hold the propeller. With the same number of twists as in the rubber band, compare the motion of the bottle.

    • Try with bottles of different size

    • Length of spokes or other parts used instead of spokes may vary depending on the size of the bottle used

    • Binding wire or nylon thread or adhesive tape can be used instead of rubber bands to hold the spokes on to the bottle.

    • Propeller material can be of plastic or a thin wooden sheet, cut out in a rectangular shape.

Finish Line

Suhail Ahanger

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