Blackboard

A panel is a base that allows easy back -to-remove label. The eg with chalk applied information can later be wiped off; The panel can then be labeled again. Boards are an economical solution for notes, practice, understanding and presentation purposes.

Development

Even from ancient times, various forms of tables for holding information is known. Depending on the culture and local conditions used to stone tablets, clay tablets, wax tablets or slates, which may have been tied together also a board book.

In Johann Amos Comenius ' Orbis pictus sensualium of 1653 we find the picture of a classroom with a blackboard with chalk labeled, so it's likely that the blackboard was already widespread at this time. The Scot James Pillans (1778-1864, Rector of the Royal High School ( Edinburgh), later a professor at the University of Edinburgh) describes in his book Physical and Classical Geography (1854 ) detailed the use of a blackboard and colored chalk in geography lessons. From 1801 to George Baron ( 1769-1812 ) have used a blackboard for teaching mathematics at the U.S. Military Academy at West Point. 1809, the first tablet was placed in a public school in Philadelphia.

Nature

Originally for today's large panels with a dark matte color used -painted wooden plates ( dark green or black in general ), since slates were too expensive in this size. Occasionally, painted papier-mâché was used. Later panel surfaces of plastic or glass were produced, modern green sheets usually have a surface made of steel enamel. They are also available with a pre-printed Ruling (similar exercise books ).

The chalk with which one writes on green sheets can easily be removed with a sponge with a damp cloth or a special table cloth, a piece of wood glued with felt. A disadvantage of green sheets is that the chalk dust generated depending on their quality when wiping the blackboard. This is especially uncomfortable for allergy sufferers, also is believed that the chalk dust creates problems in the respiratory organs. The by scratching on the chalkboard with your fingernails or - to an even greater extent - sounds harder objects produced are perceived by most people as particularly unpleasant.

Use

Green sheets were used primarily in teaching in schools and universities, but are propagated by whiteboards - so far mostly used in everyday business and in continuing education - replaced. But also in the presentation area, they are due to the simple relabelling and their partially nostalgic character often used (eg, as day passes in restaurants). Also in diving smaller writing boards made ​​of light plastic are used for communication under water, especially when hands are no longer sufficient. When writing instrument is used there is often a firmly bound with a ribbon pencil. Some of these writing boards are made of plastic, which has afterglow characteristics, thereby increasing the legibility especially in the dark.

Large panel

Wall panels are usually installed with rails and rollers on the wall and are often provided with side wings for folding and unfolding, which can be written on both sides. Smaller state boards often have the form of an easel.

Lifting or sliding panels are panels that can be moved vertically up and down. Most of them are arranged in series, so that a panel can be described, while another high position is easy to read at least two. Especially in large lecture halls has this advantage. Large Hubtafelanlagen are usually electrically powered and can be up to four panels consecutively included. There are also arrangements in front of where the panels do not run individually in parallel rails, but several per rail are arranged or the boards like a carousel forwards up and down running back again in a rail construction. Sometimes less wide Hubtafelanlagen are side by side instead of one wide, two.

The logical extension of the principle of Hubtafel are endless panels. There is actually no more panel, but only an endless ribbon of green sheet material that can be powered by hand crank or electrically so that it toward or tagging along between two wall slots. Especially for long proofs or calculations in the structural and natural sciences this is very appropriate.

Slate

Up until the 1970s were in Germany usually for writing and numeracy learning in elementary school or primary school used by students writing boards. These were made ​​to the 1960 slate, called slates, later they were replaced by plastic sheets. Chance of use of panels is even assigned to the early 1990s. On the tables were mostly diamonds on one side write lines specified on the other side. The board was kept in a stable cardboard box called panel saver. On these panels was written with a pen of that mentioned in the pen box, pen box also, were stored. The panel was cleaned with a sponge, which in turn later found in a sponge applicator place, and then dried with a cloth. The outside of the satchel for drying cloth hanging down time was mandatory. Using a slate was due to the shortage of paper and the slight possibility of correction. Originally wrote on a piece of raw shale.

The German Slate Museum in Steinach and the slate museum in Ludwigsburg city provide interesting presentations on the history of slate.