Black powder, or gunpowder, consists of sulfur as well as a fuel and an oxidizer. In the past, charcoal was always used as the fuel, while the oxidizer was potassium nitrate, also known as saltpeter. In 2014, sugar is used as the fuel in certain applications, such as in fireworks.
Black powder has been around for thousands of years, as it was first discovered by alchemists in China sometime during the ninth century A.D. The charcoal that was used as the fuel source was normally from the willow tree, but charcoals from a wide variety of other woods work as well.
Making gunpowder involves finely grinding each of the ingredients and then mixing them together. The resulting powder is extremely reactive and explodes at the slightest touch of fire. In this reaction, the sulfur acts as a stabilizing agent, while the saltpeter provides extra oxygen to allow the carbon in the charcoal to burn hotly.
When the three compounds burn together, they form carbon dioxide and nitrogen. It is the force of these gases rapidly expanding that is responsible for shooting a bullet from a gun or launching fireworks into the air. In addition to the gas, burning gunpowder also produces a large cloud of smoke. The amount of smoke depends on the ratio of the three ingredients.