Plaster of paris is made when the gypsum consistent of a fine white powder. That is calcium sulphate hemihydrate is quick fixed together all these things together hard when they are kept to dry for a long time. In ancient time it is known that plaster of paris is so called because of its preparation from the abandoned gypsum from near Paris.
Plaster of paris does not shrink or crack after it gets dry properly. It is a very good material through which we can make models and solid statues kind of stuff. It is usually used to hold the parts of ornamental plaster work that is placed on ceilings and cornices. It is also used in the medicine purpose to support the broken bones so that they can get fixed again.
Plaster of paris is prepared by heating calcium sulphate dihydrate for gypsum 212 - 180 degree Celsius that is 248 - 356 degree fahrenheit after it is dry and set it properly it can provide a really good protection to the interior surfaces.