Calcium sulfate an unusual property: when mixed with water at normal (ambient) temperatures, it quickly reverts chemically to the preferred dihydrate form, while physically "setting" to form a rigid and relatively strong gypsum crystal lattice: This reaction is exothermic and is responsible for the ease with which gypsum can be cast into various shapes including sheets (for drywall), sticks (for blackboard chalk), and molds (to immobilize broken bones, or for metal casting). Mixed with polymers, it has been used as a bone repair cement. Small amounts of calcined gypsum are added to earth to create strong structures directly from cast earth, an
What Are Little Boys Made Of? many variant forms. For example, other versions may describe boys as being made of "snaps", "frogs", "snakes", or "slugs", rather than "snips" as above. In the earliest known versions, the first ingredient for boys is either "snips" or "snigs", the latter being a Cumbrian dialect word for a small eel. The rhyme sometimes appears as part of a larger work called "What Folks Are Made Of" or "What All the World Is Made Of". Other stanzas describe what babies, young men, young women, sailors, soldiers, nurses, fathers, mothers, old men, old women, and all folks are made of. According to