Gunpowder (huo yao) is another ancient Chinese invention. It was invented by accident. More than 1,000 years ago people experimenting in a pharmacy made the discovery. They found that if sulphur, charcoal and potassium nitrate were mixed together with a certain proportion the mixture would explode.
Gunpowder changed the style of wars. The steel age ended and gunpowder-based weapons are now widely used. More than 600 years ago primitive guns were used in China. Cannon balls were propelled by the thrust of the huo yao explosion.
Now, huo yao is also widely used in fireworks. The splendid fireworks at the Beijing Olympic Games garnered wide acclaim and admiration from the audience.