Blackboards! Do they even exist, anymore? And if they do, do they still have the cursive alphabet above them? I wonder if anyone ever has to clap erasers, anymore.
Chalkboards ---another technology to feel nostalgic about.
Chalk is mineral-based---it comes from the earth. Which is why it's so much more satisfying to hold a piece of chalk than a dry erase marker. AmIright?
Here's the wiki on schoolhouse chalk:
Most people first encounter the word "chalk" in school where it refers to blackboard chalk, which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased.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 produce, and thus widely used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, and is marketed as "dustless chalk".[2] Colored chalks, pastel chalks, and sidewalk chalk (shaped into larger sticks and often colored), used to draw on sidewalks, streets, and driveways, are primarily made out of gypsum.[3]
Haha! Yeah! That's what happens!
ReplyDeleteBlackboards! Do they even exist, anymore? And if they do, do they still have the cursive alphabet above them?
ReplyDeleteI wonder if anyone ever has to clap erasers, anymore.
Chalkboards ---another technology to feel nostalgic about.
ReplyDeleteChalk is mineral-based---it comes from the earth. Which is why it's so much more satisfying to hold a piece of chalk than a dry erase marker. AmIright?
Here's the wiki on schoolhouse chalk:
Most people first encounter the word "chalk" in school where it refers to blackboard chalk, which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased.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 produce, and thus widely used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, and is marketed as "dustless chalk".[2] Colored chalks, pastel chalks, and sidewalk chalk (shaped into larger sticks and often colored), used to draw on sidewalks, streets, and driveways, are primarily made out of gypsum.[3]