I was watching A Beautiful Mind at work tonight. Several times they show John Nash doing calculations on the windows in his dorm room and in the library.
I would presume this is for cinematic effect. But I notice that this is ALSO done in Numbers
So now I wonder two things: is this really something that is common among mathematicians? If it is, why exactly? Is there some sort of benefit to doing stuff on glass, or are mathematicians so closed in, nobody’s introduced them to a dry erase board?
I only know a few mathematicians, but none of them do it.
It’s also done on CSI and in a few episodes of House, I believe.
I think the idea is that they are so focused on solving whatever puzzle has gripped their brain, they write on any available surface.
I think in Good Will Hunting Matt Damon used a bathroom mirror the same way.
One of my high school teachers used to write on tv screens and windows with a white board marker, he didn’t teach maths though.
Not a mathematician, but I carry a Sharpie in my car and write important notes on the window. Quick, easy-to-clean, hard to miss.
My mathematician husband does not do this, but my nuclear physicist friend does. I think the point is that, if the spirit moves you, you need to use any surface you can. I know that I end up with lots of scraps of papers with random thoughts stuffed into various notebooks and pockets and such.
The spontaneity thing doesn’t make sense though - In order to write on glass, you need to have a suitable writing implement such as a dry marker, grease pencil or some such.
That requires a level of preparation that makes it less spontaneous than pen or pencil and paper.
The reason, I suspect, it is done in movies and on TV, is that it permits the camera the view of the actor writing and emoting at the same time.
If you know you have a tendency to think of something off the top of your head, carrying a dry erase marker is not really any different than a pencil and a piece of paper.
I agree that the movies do it for cinematic effect, but I’m not surprised that it happens occasionally in real life.
My Mathematician dad used blackboards.
You do realize, don’t you, that A Beautiful Mind is wildly untrue to the facts of John Nash’s life? I’ve never seen a mathematician writing on a window (or on a wall, for that matter), and I’ve spent my entire career working with mathematicians. Doubtlessly someone somewhere has scribbled calculations on windows or walls, but it’s not remotely common. The writing on glass scenes were filmed because they look interesting. It’s like the scenes in the film where mathematicians present their pens to another mathematician that they admire, which has apparently never occurred anywhere.
When I was an undergrad (mechanical engineering), just about every single person I studied with (including myself) had a 3’ x 4’ dry erase board at their house.
The thing that I don’t get is that while it does make for good cinematic effect, if they actually want the audience to read what is written it’s not very effective. I find it nearly impossible to read onscreen.
Wow, did I mis-read this! Let’s just say I added another letter to ‘pens’.
I’d venture to guess that 90% of the audience wouldn’t understand what it said, anyway. Of the 10% that can, 50% probably don’t care.
I suspect it’s a lot like those computer screens that are so bright, you can see the amazing made up GUI projected on the actor.
Damn it. Damn them. I knew it was just a movie, but I wanted that part to be true.
I don’t know about glass, but I know some blooming mathematicians who used desks. That was handy as all get-out in high school. 
I had a calculus prof who’d write on the wall occasionally, but that was mostly when he was writing out a proof, or a long line of a problem being solved, and he ran out of room, but didn’t want to erase the blackboard or pause. So he’d continue onto the wall, which was annoying to us students, because white chalk on a tan wall doesn’t show up very well.
I’m in mechanical engineering and I have yet to get a white board, but I have a feeling I might have to, with some of the classes I’ll start getting as of next term!
Not a mathematician nor do I work with any. I am in a technical field and work with many engineers. Several people write on the windows when doing impromptu presentations at their desk or during hallway discussions. It’s not unusual to see windows covered with dry erase scribble.
I was in a building once which used frosted glass instead of white boards. (Note, the frosting was on the outer surface. The smooth surface was used for writing.) This was unusual enough for me to remember years later.
