DemoKindergarten3 minMeeting 23

Crookes Radiometer Spins in Light

Vanes spin faster in bright light.

Teaching & key ideas

What you do: Move radiometer between dim and bright light. What students see: Vanes spin faster in bright light. Why it works: Temperature differences around vanes and gas molecules create radiometric forces. Question to ask: Is light pushing the black side directly?

Lesson flow

Predict → demonstrate → observe → briefly explain → ask: Is light pushing the black side directly?