Crushing Can by Air Pressure
Can suddenly collapses.
Teaching & key ideas
What you do: Heat a little water in can beforehand, invert into ice water.
What students see: Can suddenly collapses.
Why it works: Steam condenses rapidly, lowering internal pressure so outside air crushes the can.
Question to ask: Is the water pulling the can inward?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: Is the water pulling the can inward?