answersLogoWhite

0

Blackboards, also known as chalkboards, were originally made from sheets of slate, a fine grained metamorphic rock derived from clay. Slate had the double advantage of being easily split into fine sheets, and having a surface just rough enough for chalk to adhere to. Quarrymen would split the sheets of slate and dress them into squares or rectangles to be mounted in classrooms.

Chalk originally was also a rock: a soft, white, porous limestone composed of calcium carbonate.

Blackboards or chalkboards were used in schoolrooms from at least the early 19th Century right down to the present, but more recently have been largely supplanted by whiteboards or dry erase boards which do not suffer from the dust problem generated by chalk. Chalkboards themselves, where still used, have not been made from slate for a long time, nor has chalk been made from limestone. Both were replaced by manufactured substitutes.

Despite the chalkboard being today pretty much obsolete, you will still hear the term "chalk talk" used when a speaker or teacher illustrates points by drawing or writing on a dry erase board or easel tablet.

User Avatar

Wiki User

16y ago

What else can I help you with?

Trending Questions
Washingtons most trusted adviser who inflicted heavy losses on Cornwallis in North Carolina prior to the battle of Yorktown? The nature of federalism has changed over time with new demands that have tended toward a system where the state and national governments share many responsibilities? Which group living in Canaan included skilled sailors and traders? If a person was drafted into the us army served on active duty from 1965 to 1967 in the us but did not actively served in Vietnam can this person be considered a Vietnam era veteran? When was George Gear born? How many states in America get tornadoes? What religion was William Tyndale? The Stars and Stripes was adopted as the new American flag in which year? Which form of government on the political spectrum is the most authoritarian? When was George Musgrove born? Sample letter request asking support from the government? What does henry david Thoreau mean when he calls government an expedient in civil disobedience? How many articles in the bill of rights? How many US Presidents served only one term and appoint the most justices? How many wives does king mswati have? Why did Congress used to investigate the government Armed Forces unions education science newspapers and other aspects of American life? Translation of the song los tres animales? What political factions made up the Legislative Assembly? Who built the New Orleans Pacific Railroad in Natchitoches Parish? What are the three most important functions of the US Supreme Court?