A
chalk board is a large, flat, dark, slightly abrasive
surface on which you
write using
chalk, which is a material that
crumbles easily and hence rubs into the irregularities of the board, producing lines. The
advantage to chalk boards is that they are easily erased using a
felt eraser.
Some people are allergic to chalk dust, so they use a whiteboard instead. Chalk boards are commonly found in classrooms, meeting rooms, and other places where a topic being dicussed can be described with drawings.