Extreme Science: Inertia Sticks

Lift a weight using centrifugal force

What you will need:

  • Drinking straw
  • String (about 2 feet in length)
  • 2 film canisters – or - several handfuls of Lego’s
  • water
  • Adult supervision

Procedure:

1) Feed string through your drinking straw.

If using film canisters:

a) tie a knot in each end of the string.

b) insert one end into a film canister with the knot inside the canister and place the lid on . the canister to hold the string in place.

c) fill the other canister with water, place the end of the string with the knot inside the . canister and place the lid on the canister to hold the string in place.

If using Lego’s:

a) tie one end of your string around a single Lego.

b) build a stack of ten Lego’s and tie the other end of the string around the Lego’s.

2) Hold the straw in one had vertically so that the end with the empty film canister (or the single Lego) is towards the top.

3) Carefully begin to twirl the straw causing the object on top to swing in a circular pattern.

What is going on?

The spinning weight on top of your straw tries to travel away from the end of the straw, but the weight on the other end of the string is holding it back so that it moves in a circle. The more you twist the straw, the faster the object spins around. When the pull of the spinning object is stronger than the downward pull of gravity on the hanging weight, the lighter object on top lifts the heavier hanging object.

Try this:

How much weight can you actually lift by spinning an empty film canister or a single Lego? Try adding more weight but be careful to make sure that everything is secure and no objects go flying off the string. We don’t want anybody to get hurt!

Radical Rick

Extreme Science

www.extremesciencefun.com