What quantity did you change?
Labs / Physics
Spinning Skater
Give the skater a spin, then slide the arms in toward the body and back out. Because angular momentum L = I × ω is conserved, shrinking the moment of inertia I makes the spin rate ω shoot up — no push required. Add weights to the hands to make the effect even stronger.
Labs / Physics / Spinning Skater
Spinning Skater
Give the skater a spin, then slide the arms in toward the body and back out. Because angular momentum L = I × ω is conserved, shrinking the moment of inertia I makes the spin rate ω shoot up — no push required. Add weights to the hands to make the effect even stronger.
Why it matters
Why explore this?
Physics explains how changes in forces, energy, motion, and matter produce results we can measure. This model lets you test one part of that relationship at a time.
Explore
Try the model
I 0.00 kg·m²ω 0.00 rad/sL 0.00 kg·m²/s
Investigate
Questions to test
Predict first, try it in the model, then use what you observe to answer.
What to try
- Pull the arms all the way in. Does the spin speed up or slow down, and by how much?
- Watch the L readout as you move the arm slider. Why does it stay put while ω changes?
- Load 5 kg into each hand and extend the arms. What happens to the spin rate now?
- With weights out, tuck the arms in fast. Can you make the skater spin faster than any push you gave it?
- If the moment of inertia doubles, what has to happen to ω to keep L the same?
Explain
Make sense of what happened
Name the quantity you changed, the quantity that responded, and the physical rule connecting them. Use a readout or visible change as evidence.
Check
Before you leave
What measurable result changed?
Which physical idea connects them?
If you can answer all three using evidence from the model, you understand the main idea. If not, return to Explore and change one setting at a time.