Drywall is made primarily from gypsum (CaSO4â¢2H2O). As its chemical formula shows, gypsum contains chemically combined water (approximately 50% by volume). When gypsum panels are exposed to fire, heat is absorbed as a portion of the combined water is driven off as steam. This chemical process is called calcination.
Image copyright Image caption Carol Ann Susi had played the role of Mrs Wolowitz since 2007. The actress best known for playing the unseen role of Howard Wolowitz's mother on The Big Bang Theory has died. Carol Ann Susi died in Los Angeles on Tuesday from cancer at the age of 62.
In 2007, Helberg was cast as Howard Wolowitz, in the CBS comedy series The Big Bang Theory. Helberg married actress Jocelyn Towne on July 15, 2007.