Convection Tube

This is a 3-foot long hollow glass tube that is bent into a square shape with a funnel-shaped opening on one side. The tube is filled with water and a pinch of potassium permanganate or a drop of food coloring is added to the opening. The tube is then heated in the corner and, as the heat is transferred from the glass to the water, the water starts to expand and rise. This pushes the dye around the tube, demonstrating the nature of a convection current. Great demo, very good visual, and everyone loves the magenta color of the potassium permanganate

Find the Lesson Plan Here