Dancing Charcoal Chemistry Demonstration

Drop a small piece of charcoal into a test tube of melted potassium nitrate and watch the charcoal dance as it burns. This is a fun and simple chemistry demonstration that illutrates decomposition and oxidation (combustion) chemical reactions.

Perform the Dancing Charcoal Chemistry Demonstration

Melt potassium nitrate (KNO₃) in a test tube. Flaming the test tube with a gas burner works well. Decomposition of the potassium nitrate releases oxygen (O₂).

2 KNO₃ → 2 KNO₂ + O₂

Take a piece of charcoal that is small enough to fit inside the test tube. Flame it with the burner to heat it and drop it into the test tube. Rapid combustion of the charcoal will occur as the carbon in the charcoal reacts with the oxygen liberated by the potassium nitrate.

C + O₂ → CO₂

The piece of charcoal will bounce around inside the test tube or 'dance' as it is oxidized.