PLASTER OF PARIS Recipe

Plaster of Paris is a Calcium sulfate semi-hydrate (CaSO₄,½ H₂O) derived from Gypsum, a calcium sulfate di-hydrate (CaSO₄, 2H₂O), by firing this mineral at relatively low temperature and thus reducing it to powder.

CaSO4,  2H2O  + HEAT -------> CaSO4, 1/2 H2O  + 1.5 H2O

In 1700’s, Paris was already the “Capital of plaster” since all the walls of wooden houses were covered with plaster, as a protection against fire. The King of France enforced rule after the big fire in England 1666.

Large Gypsum deposits near Paris ► Mined ► Manufacture of Plaster of Paris

Watch Video on How to make Plaster of Paris Step By Step Guide

Items Needed

(Apparatus) to make plaster of paris with glue

Properties of Plaster Of Paris

• It is fine hygroscopic white powder
• Its melting point is 1630C
• Its density is 2.63 g/cm³
• It sets quickly on mixing with water giving out heat
• Expands slightly on setting

USES of Plaster of Paris

• Because of its property of slight expansion on setting, it is used for filling cracks and holes in plaster
• It is also used for filling cracks and knots in wooden surface before painting polishing
• Plaster of Paris is used in making surgical bandages where movable parts of the body are to be held rigidly in place
• It is used in chalk
• As plaster of Paris has high melting point, it is used for plastering the walls of wooden houses, such as a protection against fire
• It is used for making models and statues

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