Pyrotechnics is the science and craft of creating fireworks, but also includes safety matches, oxygen candles, explosive bolts, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. This trade relies upon self-contained and self-sustained exothermic chemical reactions to make heat, light, gas, smoke and/or sound. The name comes from the Greek words pyr and technikós.