Boiling water with a Bunsen burner. The Bunsen burner is fuelled by hydrocarbon gases to produce a flame. It is used in the laboratory as a heat source, here to boil the water in the beaker. The Bunsen burner vent is in its open position, drawing air into the combustion mixture, leading to a stronger, hotter, blue flame. The gauze provides support for what is being heated, and also helps to spread the heat evenly. Pure water boils at a temperature of 100 degrees Celsius at standard atmospheric pressure.