Tornado in a Bottle
A visible funnel forms.
Teaching & key ideas
What you do: Swirl water strongly before letting it drain.
What students see: A visible funnel forms.
Why it works: Rotating water forms a vortex with lower pressure near the center.
Question to ask: What shape does the spinning water make?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: What shape does the spinning water make?