Oil-and-Water Lava Lamp
Colored blobs rise and fall.
Teaching & key ideas
What you do: Add tablet pieces to layered oil/water.
What students see: Colored blobs rise and fall.
Why it works: Gas bubbles carry denser water upward; when bubbles pop, water sinks.
Question to ask: Why do the colored blobs come back down?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: Why do the colored blobs come back down?