Generally, blackboards are associated with education and schooling. Blackboards have existed since approximately 1800. They were the first source of mass communication in the classroom. The introduction of blackboards for use by teachers allowed them to teach a whole room of children.
Previously children had to be taught individually or in very small groups using slates. Before the use of slate in education, there was no cost effective way for educators to write out their own ideas, for children to follow. The blackboard revolutionised methods of education and introduced education for the masses.
A standard blackboard is simply a piece of board painted with matte black paint. The first blackboards were mounted on easels, in the same way as a canvas for painting purposes. This simple concept progressed to the production of wall-mounted boards. Black plastic on wall-mounted rollers followed, which could be scrolled to allow more area. An increase in the area available for writing allowed more content from a lecture to be stored and referred to repeatedly as required.
The most famous blackboard is arguably that used by Albert Einstein. On 16 May 1931, Einstein gave a lecture at Oxford University. The blackboard, which he used to assist with the lecture, is preserved and displayed at the Museum of the History of Science, in Oxford. I do wonder if any other class would have been so keen to reserve any blackboard notes from their education.
The most basic blackboard is hardboard with an application of matte black paint. The crème de la crème of blackboards is steel enamelled with porcelain. This type of blackboard is very hardwearing and long lasting. Although technically it is no longer a blackboard, but is still described as such. The only similarity is now that all versions of the humble blackboard use the medium of chalk for writing on the surface.
Chalk is basically a composite of sedimentary marine rock. Most people have seen and used rock and know what it looks and feels like. It is usually white and formed into sticks, which is ideal for use on a blackboard. Chalk is fragile, breaks easily and creates a lot of dust. Most modern blackboard chalk is produced using gypsum or calcium sulfate. Gypsum is a very common mineral and is a form of alabaster.
Many people, of a certain age, will definitely have memories of the tool used to clean the chalk from the blackboard. This may be the case, even if they have only the vaguest memories of what was written on the board. Frequently, in the days before the dawn of personal injury lawyers, teachers would use blackboard dusters as missiles. This was a tactic used to elicit 100% attention in class.
More recently, whiteboards are replacing blackboards in universities and schools. Whiteboards are written on using erasable markers, this certainly cuts out the dust created by chalk and dusters. The blackboard has many other competitors in overhead projectors used to display acetate pages. Web content can also be displayed directly onto screens. Lectures can be accessed online, therefore students need not even be in class to keep-up-to-date.
There is good news for blackboards, despite all the technology available and LED and neon display boards. Blackboards are increasingly used for display in the smartest of pubs and restaurants. The wine and cask ales list and menus are lovingly written alongside chalked artwork.