Dancing Raisins
Raisins repeatedly rise and sink.
Teaching & key ideas
What you do: Drop raisins into fresh carbonated water.
What students see: Raisins repeatedly rise and sink.
Why it works: Gas bubbles attach, lower average density, then pop at the top.
Question to ask: What is making the raisins go up?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: What is making the raisins go up?