I feel that I have to say a few words in defence of blackboards (chalkboards).

The following observation belongs to the great mathematician Israel Gelfand. Using chalk on a blackboard, we write by moving the entire arm. With felt markers on a whiteboard, we use smaller scale movements of fingers and the wrist. At a purely instinctive, physiological level, people tend to hold breath when they do small movements with their fingers. On the contrary, wider movements of arms fit naturally in the cycle of breathing and speaking. In mathematics teaching, we have to write on the blackboard and speak more or less simultaneously (although I take care to never speak “to the blackboard” and turn to face the audience every time I utter a word – but I do keep chalk pressed against the board, thus ensuring that I continue writing exactly from the spot where I stopped). In a lecture, the lecturer has to speak clearly, loudly and project his/her voice onto the audience, filling the whole room with the sound. Ever tried to do that while writing with a thin pen on a visualiser plate (yet another horrible contraption found in many lecture rooms)?

Whiteboards are OK in a small class (and, in my office, I have a whiteboard – for reasons of dust etc.) But I teach lectures to up to 400 students. Psychological dynamics of interaction with big audience is quite different from that of a small class — see more on that in my old blogpost Psychophysiology of blackboard teaching and More on Blackboards. Good very big chalkboards are much more preferable in that environment. Quality ceramic blackboards do exist. This mug (a gift to me from a student)

This size of chalk makes writing on the board readable from the most distant back row. By the way, in large lecture theatres, bright colours have to be used with care: 1 in 20 people have some deficiency of perception of colours, and colour-coding of information could be very confusing for them. In the audience of 400, 1 in 20 make 20 people.

This size of chalk makes writing on the board readable from the most distant back row. By the way, in large lecture theatres, bright colours have to be used with care: 1 in 20 people have some deficiency of perception of colours, and colour-coding of information could be very confusing for them. In the audience of 400, 1 in 20 make 20 people.

IMHO, chalkboards were replaced by whiteboards for basic economic reasons: quality glass or ceramic chalkboards are much better than plastic whiteboards – but they are more expensive to buy, and are more expensive to maintain – regular washing of chalkboards and vacuuming chalk dust requires hiring more cleaners. But, remarkably, chalkboards are used in Japan, apparently for pedagogical reasons — see Lessons Learned from a Chalkboard: Slow and Steady Technology Integration (Bradley Emerling). But low quality chalkboards can be cheaper than whiteboards, and for that reason survive in poorer schools and universities: