Oil-and-Water Lava Lamp

Colored blobs rise and fall. Ask students to predict what will happen. Add tablet pieces to layered oil/water. Key idea: Gas bubbles carry denser water upward; when bubbles pop, water sinks. Ask: Why do the colored blobs come back down? Safety and cleanup: Bottle stays open or loosely capped during reaction. https://www.google.com/search?q=%22Oil-and-Water+Lava+Lamp%22+science+demonstration+experiment