But what if someone Zoom-bombs the strip tease with a lecture on quantum mechanics?

thorpe: Xcott: You could probably make a bazillion dollars if you invented an economic alternative to whiteboards that looked like a chalkboard, or otherwise offered high contrast in most lighting conditions.

There are paper alternatives that have been around for decades. Nobody would use them because they've been around for decades. Cut to fit, tape up, use for a day, take down. Next day same routine.

I had a student capstone project to design a portable blackboard to use in place of a crappy classroom whiteboard.  In the end we discovered that you can buy blackboard fabric (basically vinyl-coated burlap) and bring a big roll of it into the room to hang over the whiteboard.  It was too heavy, awkward and curly (and you'd get chalkdust upon the sofa, sofaaa) but we still use the prototype chalkboard scrolls in the lab, where they can be placed around the room conveniently.

We also discovered that black butchers block paper is a cheap chalkboard surface that works moderately well, and is lightweight and easy to tape over a whiteboard.  However, it doesn't last very long and therefore produces considerable waste.

In either case, however, the chalkdust would harm the AV equipment in the long run.  What we really need is a dry-erase alternative that has the contrast and visibility of a chalkboard (meaning it can't be shiny!) and which endures use and abuse like a chalkboard.  There are melamine whiteboards with decent contrast but they last a month in a college classroom---that's why we almost always use glassboards, which are visually terrible.

Hyjamon: also, whiteboards are more common now it seems in education.

They are, but they suck.

Whiteboards and glassboards have replaced chalkboards for lots of reasons, one being that chalkdust screws up AV equipment in the classroom.  But they're really hard to read from a distance or certain angles due to glare (especially if a classroom has windows,) and many whiteboard surfaces lose their dry-erase property very easily.  This has only gotten worse now that we have to go online, because even a high-quality camera aimed at a classroom whiteboard/glassboard is close to useless.

You could probably make a bazillion dollars if you invented an economic alternative to whiteboards that looked like a chalkboard, or otherwise offered high contrast in most lighting conditions.

As for chalkboard formulas in movies, you probably dug the mathematics lecture in Sneakers.