Explosive reactions occur when a chemical reaction releases a large amount of energy in a very short time, resulting in a rapid expansion of gases. This can create shock waves and high temperatures, often leading to an explosion. Common examples include the combustion of fuels and the reactions of certain chemicals like dynamite or gunpowder. These reactions can be classified into two main types: physical explosions, which involve a change in state, and chemical explosions, which involve a change in chemical composition. Safety measures are crucial when handling materials that can undergo explosive reactions to prevent accidents and injuries.