Blackboard

A blackboard, also called a chalkboard, is a surface on which chalk is visible.^[1] It is used as a surface to write on. It is usually made up of wood or fiber. It is painted black to reflect the white chalks.

Blackboards are often used to help in teaching in school. Blackboards are not used as much now but can be seen in some schools still. The chalk dust got everywhere, and some people are allergic to chalk dust. Now people use whiteboards: they can take modern felt-tip colour markers, and clean easily.

Schoolteachers often use the chalkboard to display things at large. It also makes the learning cooperative between teachers and student. Chalkboards can be black or dark green, in which case they may be called blackboards and greenboards.

Blackboard Media

A chalkboard with an eraser in the chalk tray
Stick-slip effect with a chalk on a blackboard
Sound of mathematical formulas written with a chalk stick on a blackboard
Retouched drawing of a teacher at blackboard for an advertisement, 1924
An advertising blackboard in Taipei, Taiwan, 2019
Mathematics on a board, 2017
Teacher explaining the decimal system of weights using a blackboard, Guinea-Bissau, 1974
An Austrian chemist with colored chalk, 1970
A schoolboy in Seattle, WA, USA, 1961

Notes

↑ Originally, actual geological chalk was used. However, in the 20th century it was an artifical product.

[1] Originally, actual geological chalk was used. However, in the 20th century it was an artifical product.

[1]