To demonstration the use of catalyst in a combustion of sugar cube.
A catalyst is a substance used in chemistry that facilitates a chemical reaction to take place in its presence, but does not actually itself change during the chemical reaction. The catalyst can be demonstrated with a sugar cube, a small amount of ash, and matches. First try to set fire to the sugar cube with a match. This will be impossible. Then rub a small amount of ash on one side of the cube and set fire again. This time the sugar cube will catch fire and burns steadily. The catalyst is the ash and its presence causes the sugar to ignite. The ash itself is not combustible and remains unchanged throughout the combustion process.