Which is the major component of blackboard chalk?
A soft, chalky stick used to write on blackboards by students and teachers since the early 1800s. Blackboard chalk originally contained Calcium carbonate typically bound with kaolin clay, Oleic acid, and Sodium hydroxide. A wide variety of formulations are now used, most of which are made from calcium sulfate hemihydratex, which reacts with water to form Gypsum. Dry pigments may be added for increased whiteness or coloration.
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cameo.mfa.org
What are your thoughts on this subject?
10 Comments
earlepg
If you've ever used chalk to write on a blackboard, please raise your hand.
Chip Combs
Seriously Lilly, thanks for a decent question w decent answers.
Edie Koller
When I was a kid back in the early 1950's I had a job of clapping the eraser outside after class.
Richard D. Boyle
Blackboard Jungle 1948-1952.
Roslyn Russell
earlepg, too right - teaching in schools in New South Wales, Australia in the 1970s.
Mary McAvinew Bowles
getting picked by your teacher to take the erasers outside, to "clap" them.
Julie Allen
krkyates, Question should read what used to be the major component of blackboard chalk?
Chip Combs
Whatever happened to "An Actor" as one of the choices???
Noella Ross
earlepg, all through primary and high school, and beyond.
Nickey Welsh
earlepg, Thousands of times ! From 1964 to 2000,