Chalk It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are then consolidated and compressed during diagenesis into chalk rock. Most people first encounter the word "chalk" in school where it refers to blackboard chalk, which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased. Blackboard chalk manufacture now may utilize mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum (calcium sulfate). While gypsum-based blackboard chalk is the lowest cost to
Vezo people catches that men bring them. With what they earn, women buy rice, the staple food, other essential foodstuff and a variety of luxury items. Children go to school in the one village school building, where there are two designated teachers. However, due to the deterioration of public administration in Madagascar, the building and the teachers are hardly ever occupied. Whenever children are in the building, and if the teacher has not run out of chalk, the teaching largely consists in copying letters, numbers, and short sentences from the blackboard onto the child's own A5 size blackboard. Understandably, the many children