Plaster of Paris

Secure some plaster of Paris and mix a small amount with water. It must be worked quickly or it will harden whereas being mixed. Place the mixture in moulds and let it set unless very hard. Study the appearance and properties of the samples. 3 Collections of building materials Collect samples of all the dissimilar types of rock or mineral building materials available in your locality like as marble, granite, slate, limestone, brick, cement, plaster, etc. These may be added to your collection after proper labels have been close to the samples