A tealight is lit from a Bunsen burner, until the wax itself burns. Then 3ml of water is sprayed onto the burning wax from a spray bottle. The wax bursts violently into flames almost a metre high.
How does it work?
The wax is heated so much that its temperature, about 280°C, exceeds the self-combustion point. The wax then burns without a wick. When water is sprayed onto the liquid wax it evaporates very rapidly, as the temperature of the wax is also above the boiling point of water (100°C). The resulting stream pulls the wax with it, rising upwards. This causes the surface to air ratio to increase so much that all the tealight wax burns at once.
Safety Tips
The wax burns in a split-second, so the danger of a fire spreading is minimal. During the experiment only our trained presenters are on the stage. Should something unexpected occur, there is always a fire extinguisher available on the stage to easily put out any fire. We also lay a fire blanket beneath the experiment so no hot wax splatters the floor. If in doubt, please contact a trained firefighter to approve the experiment and implement it as safely as possible.
If you wish we can scale this up a little bit...
