Breaking Pole Paradox: printable worksheets

Choose the sheet for the learner's age. Each prints on a single page. Build the project first, then fill it in together.

Ages 5-7: Draw & tell

Name: ______________________Date: ____________

Homemade Science with Bruce Yeany · Breaking Pole Paradox · Ages 5-7

Snap! Do the Cups Fall?

Watch the spaghetti snap. Look at the cups.

1. Guess first: when the spaghetti snaps, the cups will...

◯ Fall over◯ Stay standing

2. Draw the spaghetti on the two cups before the chop.

3. Draw what happened after the chop. Where did the pieces go?

4. Which made the cups move more?

◯ A slow push◯ A fast chop

5. One word for things that like to stay still:

Ages 8-10: Predict, test & record

Name: ______________________Date: ____________

Homemade Science with Bruce Yeany · Breaking Pole Paradox · Ages 8-10

Predict, test, and record what the cups do.

1. Predict: what will the cups do when a grown-up chops the spaghetti fast? What about a slow push?

2. Record each try.

3. Right after the snap, the outer ends of the pieces...

◯ Pushed down on the cups◯ Flipped up and away

4. What did you find out?

5. Why do you think the fast chop didn't knock the cups over? Use the word inertia.

Ages 11-14: Explain & design your own test

Name: ______________________Date: ____________

Homemade Science with Bruce Yeany · Breaking Pole Paradox · Ages 11-14

Explain the breaking-stick paradox with inertia and center of mass.

1. State Newton's first law in your own words.

2. Use inertia to explain why a fast chop leaves the cups standing but a slow push tips them.

3. After the break, each piece rotates around its own center of mass. Explain why that makes its outer end lift off the cup.

4. In your tests, what did you change, what did you observe, and what did you keep the same?

5. Plan a fair test of one more variable (for example, how far the ends rest on the rims, or the stick's thickness).

6. Bruce's last try failed when the pieces hit the box under a glass. How would you redesign the setup?

7. Where else does inertia keep something still while something underneath moves quickly?

Answer guide for grown-ups

Homemade Science with Bruce Yeany · Breaking Pole Paradox · Answer guide

Any prediction is fine; it gets tested next.
Open answer: look for effort and careful observation.
Flipped up and away
A fast chop snaps the spaghetti and the cups usually stay standing. A slow push drags the ends and can tip or slide the cups.
The ends of the spaghetti have inertia, so they stay still. The chop is so fast that the spaghetti breaks before the ends start moving, so the push never reaches the cups.

An object at rest stays at rest, and an object in motion keeps moving at the same speed and direction, unless an unbalanced force acts on it.
The ends resist a change in motion (inertia). A fast chop snaps the stick in a tiny time, before the ends are accelerated, and once it's broken no force is carried to the cups. A slow push has time to pass the force along the stick to the cups, so they tip.
The downward hit lands on the broken end, off the piece's center of mass, so the piece spins around its center of mass like a seesaw: the broken end goes down and the outer end goes up, away from the rim.
Changed: fast chop vs slow push (or where the strike landed). Observed: whether the spaghetti broke and whether the cups moved. Kept the same: the spaghetti, cups, water level, book height, how far the ends rested on the rims.
Open answer: look for effort and careful observation.
Examples: move the supports so nothing sits in the path of the turning pieces, make the supports narrower than the cups, rest the ends less far onto the rims, or strike exactly in the middle.
Examples: the coin-on-a-card trick, the tablecloth trick, knocking the bottom coin out of a stack, pulling a sheet of paper fast from under a cup, a hammer driving a nail into a heavy block.