Fire is the rapid oxidation of a material in the exothermic chemical process of combustion,releasing heat,light,and various reaction products.When a fire break out we should leave the scence of the fire as soon as possible.If there is thick smoke we must find a wet towel to cover our mouths to prevent from smathering.When a fire breaks out in a building we must follow the escape sign to get out the building as soon as we can.