We also saw in class that an ordinary piece of platinum foil can act as a heterogeneous or contact catalyst to speed up the oxidation of methane. Heating the platinum in the burner flame is necessary to get the reaction to persist, but once the metal is hot enough, the gas to the burner is briefly interrupted and then allowed to flow again. The flame goes out, but the platinum continues to glow from the heat of the reaction. Methane is still being converted into water vapor and carbon dioxide by reaction with oxygen from the air, but the reaction now takes place exclusively on the surface of the platinum, not in a flame.