A chalkboard or blackboard is a reusable writing surface on which text or drawings are made with chalk or other erasable markers .Black boards were originally made of smooth, thin sheets of black or dark grey slate stone. Modern versions are often green or brown and are thus sometimes called a green board or brown board instead.
          A blackboard 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 enameled steel (black, green, blue or sometimes other colors). Porcelain is very hard wearing and chalkboards made of porcelain usually last 10-20 years in intensive use.
Blackboards have disadvantages:
They produce a fair amount of dust, 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.
The scratching of fingernails on a blackboard is a sound that is well-known for being extremely irritating.
Blackboards are also used in many establishments (typically public houses) as a form of advertising often for upcoming events and menus - as well as to keep the score in darts matches
Sometimes called a flannel graph.
This teaching tool is called by different names:
 Visual Board , Frick Board,  Slap Board,  Felt Board, Coherograph, Video graph
Flannelgraph is a storytelling system that uses a board covered with flannel fabric, usually resting on an easel. It is very similar to Fuzzy felt, although its primary use is as a storytelling medium, rather than as a toy
How to use
The principle involved is the inter1ooking of fibers of two rough or bairy surfaces, so that the pieces pressed on to a background which is hard and vertical will stay. It can be illustrated on a larger scale by pressing two tooth brushes or hair brushes together, so the bristle inter-1ook. In case of flannel graph similar principle of friction helps an object to cling to the surface of the board.
The flannel board is usually painted to depict a background scene appropriate to the story being told. Paper cutouts of characters and objects in the story are then placeon the board, and moved around, as the story unfolds. These cutouts are backed, either with flannel, or with some other substance that adheres lightly to the flannelbackground, such as coarse sandpaper.
1) Permits numerous and varied arrangements of visua1 materials.
2) Permits the use of either chart or small pieces of material Materials can be packed and transported complete notes. 3) Permits the development of a complete story.
4) Promotes conscientious planning, which must precede the development of the material in the first place.
5) Challenges one to develop symbols to portray such things as abstractions.
 6) Easier to construct materials for flannel board than to make slides or movies.
1) Transportation and storing of boards and materials is a problem. Suitable tables to support boards must be available.
2) Time and cost of making material for presentation present a problem.
3) Cost of boards themselves can't be overlooked.
 4) Presentation is limited a new idea involves a lapse of time before the new material can be added
.5) Might tend to deter one from using other more effective methods and techniques when it is evident that other methods might be more appropriate.
6) To tell a complete story it often takes either too much board space or smaller designs and materials some of which cannot be seen well.
It is a soft board which will hold pins or tags almost suitable. Simple device placed either indoor or outdoor. Items generally displayed are photographs, publications, posters, news paper cut outs.
Explains important events Reports special activities
Not effective for illiterate group.
Takes lot of preplanning and preparation
A bulletin board (pin board, pin board or notice board in British English) is a place where people can leave public messages, for example, to advertise things to buy or sell, announce events or provide information. Dormitory corridors, well-trafficked hallways, lobbies, and freestanding kiosks often have cork boards attached to facilitate the posting of notices. At some universities, lampposts, bollards, trees, and walls often become impromptu postering sites in areas where official boards are sparse in number.
It is a type of board which contains small holes to fix certain letters into the holes which is used especially in the offices to display certain items, name of the personal or faculty member.
It is a framed iron sheet carrying porcelain coating in some dark color generally black or green. It can be used to display pictures, cutouts and light objects with disc magnets or magnetic holders.
Movement of visual material is easy.
These are also an effective aid, usually radios, recorders, gram phones come under this category.
Using a record player for teaching:
-A record player can be used in the following ways in the actual class room situation
A record player can be used to supplement a lesson.
A record player can be used for an appreciation lesson in music.
A record player can be used for an appreciation lesson in literature.
A record player can be used for students to acquire the singing ability, deliver a speech properly, and recite a poem in the right way.
The player can be used to end or conclude a lesson;
Introduce a lesson and review a lesson.
A record player can be used for physical exercises accompanied with music
A tape recorder is a portable electronic gadget to record, reproduce, erase and re record sound on a magnetic tape. This device can be used without much fuss by any body by operating the following press buttons attached to the recorder, viz, stop, play, wind, rewind, record, pause, and eject.
Uses: it is used to learn foreign languages, rhymes, and songs with clarity. GRAME PHONES Like radio gramophones are also important teaching devices. Helps to listen to famous speeches
To teach good pronunciation in a foreign