Chalkboard goes clear back, nearly, to the first organized school classroom. For sure, many 100’s of years back. Before that, they used a charcoal stick and drew using whatever smooth surface usable. The difficulty was, charcoal isn’t erasable, so a clean writing surface was required quite often. Before they needed chalk boards, somebody had to invent chalk for the chalk boards. It was learned ground up limestone produced a white powder that could be compressed into a soft white stick that would produce a white line as compared to the black that a burnt stick left. The really good part was that it wiped off of a smooth stone face. (continue reading…)