Who would have thought there was so much science in a cake of soap?! The soap in this kit can be melted and moulded to make almost any solid shape. Whipping the soap creates a stable foam that can be piped onto soap cakes to make any sweet creation you can imagine. The clear glycerine soap allows light to pass through, but when the soap is whipped with air, it becomes an opaque, white foam! Adding white pigment or colour to the clear soap changes how the soap looks because it changes which colours of light are absorbed or by the soap.