Name the agent that makes the blackboard black?
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They are made of smooth sheets of black slate stone.
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A blackboard or the chalkboard is made of thin sheets of dark grey or else smooth black slate stone. It's surface can be used for writing, It can be used again and again. People use calcium sulfate or calcium carbonate stick known as chalk to write on it.
It was first used by James Pillans in 1801, who was the headmaster and geography teacher in the Old High School, Edinburgh. He was the one who hung a big piece of slate on the wall in the classroom and used it for teaching for the first time.
The blackboard does not reflect any color and therefore it is black.
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