Saturday, March 7, 2009

History of chalkboard ( Magnetic Chalkboard Paint )

( Magnetic Chalkboard Paint )

History of chalkboard begin as early as 18th century. The earliest blackboards cannot properly be called chalkboards, as there was no chalk involved. They were simply small pieces of slate, and instead of chalk children would use another, smaller piece of slate to write on the board. Marks would be erased with a simple rag in order for the student to move onto the next problem.

In the late 18th and early 19th century, such "slateboards" were commonly used in schools in the United States and other countries. These small pieces of slate would be bound in a wooden frame to help strengthen the board and keep them from cracking. In those days paper was expensive and hard to come by, so these mini slate blackboards provided a good substitute.

At some point in time, however, these slate boards began to be used in a brand new way. A geography teacher working in Scotland is reported to have taken the slates from the students and hung them all on the wall. He then used this to make-shift blackboard to write out geography information which all the students could read at once. A revolution in blackboard usage had begun.

By the 1850's, virtually all schoolhouses included a blackboard along with their other staples: a wood burning stove and benches for the students to sit on. Still, however, our modern chalkboards were not in common usage.

As technology progressed, the old pieces of slate finally began to be replaced by chalk. The soft limestone chalk was easier to use on the boards, and easier to clean as well. The old rag erasers have been erased by new felt chalkboard erasers, which are able to absorb more of the chalk dust and keep it out of the air. The boards themselves are no longer made of slate, but instead are a steel sheet with a porcelain enamel.

( Magnetic Chalkboard Paint )

Introduction ( Magnetic Chalkboard Paint )

( Magnetic Chalkboard Paint )

According to Wikipedia, A chalkboard or blackboard is a reusable writing surface on which text or drawings are made with sticks of calcium sulfate, known, when used for this purpose, as chalk. Blackboards were originally made of smooth, thin sheets of black or dark grey stone stone. Modern versions are often green or brown and are thus sometimes called a greenboard or brownboard instead.
A chalkboard can simply be a piece of board painted with matte dark paint (usually black or dark green). A more modern variation consists of a coiled sheet of plastic drawn across two parallel rollers, which can be scrolled to create additional writing space while saving what has been written. The highest grade chalkboards are made of a rougher version porcelain enamelled steel (black, green, blue or sometimes other colours). Porcelain is very hard wearing and chalkboards made of porcelain usually last 10-20 years in intensive use.

Chalkboards have disadvantages: they produce dust, the amount depending on the quality of chalk used. Some people find this uncomfortable or may be allergic to it, and there has been speculation about links between chalk dust and respiratory problems. The dust also precludes the use of chalk in areas shared with dust-sensitive equipment such as computers. However, these alternative methods of displaying information have drawbacks of their own.

Why sometimes it is called chalkboard and sometimes blackboard? Whats are the different? We will cover this story in the next post.

( Magnetic Chalkboard Paint )