While we like our slides (see News on 29/09/24) and use them in seminars and teaching all the time, mathematicians have always had a fondness for chalk. It can take ages to craft a new diagram or to sketch a new proof on the board, but it is a lot easier than working on scraps of paper and trying to keep tabs on all the pages.
Sometimes it is necessary to work on the board for several days to complete an idea, and you quickly learn as a young lecturer to write DO NOT ERASE in large letters on any board that you want to come back to. Of course that depends on the cleaner reading that part of the board first. I remember the horror of returning to a whole week’s work after a day off to find the entire set of boards erased except for the boxed phrase “DO NOT ERASE”. Luckily we had taken a photo before leaving for the weekend, but it still took the rest of that morning to reconstruct the boards from the image.
The photographer Jessica Wynn was so intrigued by the beauty and mystery of the mathematical chalk board that she published a book about them, including some by my friend and colleague Prof Benson Farb. His department at the University of Chicago wrote an article about it which you can find here.