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A chalkboard is a piece of slate on which to write with chalk and is named after the color "black".
A blackboard is a large flat surface, finished with black slate or a similar material, which can be written upon with chalk and subsequently erased.
A traditional blackboard is typically made of a smooth sheet of slate or a chalkboard paint-coated surface attached to a wooden frame. Slate blackboards are known for their durability and smooth writing surface, while chalkboard paint-coated surfaces allow for easy customization on various materials such as wood or metal.
Pizarra is a grey mineral slate or a blackboard
Blackboards used to be made of black slate, hence the name "blackboard". As technology evolved, most blackboards are now made of green materials like porcelain or laminate, but the original name stuck. The common usage of the term "blackboard" persists even though the color is green.
When I was a student, it was slate. Then "greenboards" came, made of composite material, lighter and more easily maintained. Not much longer until "whiteboarding" economics of scale click in.
The Sanskrit term for blackboard is "कृष्णपट्टिका" (pronounced as krishnapattika). In this compound word, "कृष्ण" (krishna) means black, and "पट्टिका" (pattika) refers to a board or slate. So, when translated literally, "कृष्णपट्टिका" means a black board or slate used for writing or drawing.
Slate
Originally they were made of thin sheets of a type of rock known as slate- which is very dark gray (black) in color. Later they used a man manmade material that was lighter and cheaper, and changed the color to green- better visibility. But we still use the old name.
"el pizarron" means "the slate" or "chalkboard"
very different it was strict and you wrote on slate with chalk[mini blackboard with chalk]
Slate siding is made from the metamorphic rock slate.