Ever wonder what walls are made of? Join twins Brayden and Kaleb as they discover that the walls of BK Playhouse are actually made out of a mineral called gypsum! First, they will need to go mine for gypsum and other minerals and rocks just like a real geologist! Then once back at BK Playhouse, they will smash the gypsum with hammers, mix it with water and create their own Plaster of Paris to make dry wall with! Why is it called Plaster of “Paris”? Watch and see!