If we are getting gypsum when POP is mixed with water then why should be gypsum heated to get POP?? Can't we use gypsum itself??

If we are getting gypsum when POP is mixed with water then why should

1.	If we are getting gypsum when POP is mixed with water then why should be gypsum heated to get POP?? Can't we use gypsum itself??
Answer» bcz gypsum is hard SOLID subs.which is totally DIFFERENT from POP