About Chalk Boards

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About Chalk Boards
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A Piece Of Chalk

• The chalkboard is a flat, vertical writing
  surface on which anything can be inscribed by
  means of a piece of chalk. The device is
  generally used for educational purposes, but it
  can also be found in the workplace

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A Variety Of Materials

• While chalkboards can be manufactured from a
  variety of materials, porcelain enamel is the
  most common material used in today's chalkboard.

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The Origins Of The Chalkboard

• The origins of the chalkboard date back to the
  early decades of the 19th century. The forerunner
  of the chalkboard was the small, paddle-shaped
  hornbook

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Use In Schools

• This item had been in use in schools of medieval
  England, and by the time of the Revolutionary War
  era in colonial America, it was chalk board
  carried by legions of students.

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Revolutionary War Era

• Revolutionary War era in colonial America, it was
  carried by legions of students. The hornbook was
  a strip of wood with a piece of paper fastened
  onto it.

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A Variety Of Learning Aids

• On the paper were a variety of learning aids in
  small print. A typical hornbook would carry both
  the Lord's Prayer and the alphabet, and a
  translucent sheet of animal horn covered the
  paper.

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The Reading Chalk Board

• Eventually the hornbook evolved into the reading
  board. This was a strip of about 15 inches (38
  cm) in length, also containing the alphabet and
  other learning aids

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Chalkboard For All Students

• From the reading board came the concept of one
  general chalkboard for all students in the
  classroom to both view and use

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The Early Chalkboards

• The early chalkboards were simple pine boards
  painted black. In other cases, a combination of
  lime, plaster of Paris (a white powdery
  substance), and lampblack (fine black soot) chalk
  board was spread on the classroom wall.

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Most Modern Chalkboards

• Most modern chalkboards are made of porcelain
  enamel. In this particular manufacturing process,
  a tough and durable material such as steel is
  used as the base.

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Manufacture Of Chalkboards

• There are several thicknesses of steel used in
  the manufacture of chalkboards, but the most
  common is 22-gauge. Another crucial element is
  silica

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Surface Of A Chalkboard

• The surface of a chalkboard is usually a blend of
  inorganic compounds such as a powdered glass
  opacifier and oxides, an organic element that
  provides color to the coating material.

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