Blackboard ‘chalk’ are produced especially for use with blackboards in white and also in various colours. White chalk sticks are made mainly from calcium carbonate derived from mineral chalk rock or limestone, while colored or pastel chalks are made from calcium sulfate in its dihydrate form, CaSO·2HO, derived from gypsum. Chalk sticks containing calcium carbonate typically contain 40–60% of CaCO (calcite). As compared to whiteboards, blackboards still have a variety of advantages: On the other hand, chalk produces dust, the amount depending on the quality of chalk used. Some people find this uncomfortable or may be allergic to it, and according
Simon in the Land of Chalk Drawings Simon in the Land of Chalk Drawings Simon in the Land of Chalk Drawings is a British children's animated series about the adventures of a young child named Simon, who has a magic blackboard. Things that Simon draws on the chalkboard become real in the Land of Chalk Drawings, which Simon can enter by climbing over a fence near his home with a ladder. The stories often revolve around the unintended effects that Simon's drawings have on the Land of Chalk Drawings, such as when an upset Simon draws a picture of his angry self, which goes on a rampage.