Hell in a tube
Nitre (potassium nitrate) is a strong oxidizing agent. The powder mixture with sulfur and charcoal reacts explosively after ignition. An interesting experiment is the reaction of molten nitrate with compact wood Uli powder and sulfur.
The tube is filled to about one third of powdered potassium nitrate and fix it to the terminal rack. Under the tube insert a metal plate with sand (during the reaction may be melting the bottom of the tube). The gas burning gently along the length of the tube heat the nitrate until it is melted and then heating is interrupted.
in the flame of the burner Heat the piece of charcoal and throws him into the tube (working with a shield - a risk of splashing of molten nitrate)) with molten nitrate. Hot coals will burn and hop. After calming the reaction (carbon uz neposkakuje) Pour into a tube small teaspoon of powdered sulfur. The reaction is exotermnější and there is intense devel light.