4B20.10 • Convection: Convection Tube with Water

Location: Cabinet 10

Photo of University of Texas at Austin's Demonstration

Instructions / Notes:

• Note: Do not place tube over bunsen without water! If you do on accident, let it cool down completely before adding water. It WILL crack if you don't.
• A circle made with glass tubing is filled to the top with water.
• A gas torch is used below the tubing to heat either the right or left side.
• Convection begins within a few seconds of heating the water within the tube.
• Add a few drops of colored water to the top opening to enable students to see the effect.

Concept Conveyed:

• The water on the side with the gas torch expands and rises as it heats up.
• The water from the other side fills in the space as the hot water rises, resulting in a circular convection pattern.

Demo Staff:

• Water does not come colored. Include small beaker with water and dye SEPARATELY.

Last updated on April 27, 2026