Old School

Apparently, world-class mathematicians prefer to work on blackboards more than any other medium. (And some have quite a taste for high-quality chalk.) One might think that blackboards would be considered too restrictive, too slow, too imprecise for high-powered math—clearly a job for high-speed, hi-res, high-tech computers.

But I can see their point: chalkboards are an enormous expanse of real estate to work out both abstract theories and concrete expressions, and you can look at your work up close or at a distance with a field of view that computer screens have yet to match.

And chalk: a substance that allows for quick erasure, deliberate smudging and modification; variation in line weight and shading. My high-school physics teacher had a favorite technique for drawing dotted lines: holding it at a steep angle to the board while “pushing” it would make it skip along the surface. With a little practice, you could produce a long arc of beautifully spaced dashes. Imagine another writing tool that gives you such immediate access to such a wide variety of techniques! (Charcoal, perhaps?)

Working at a blackboard is inherently kinesthetic: standing (sometimes crouching!), moving side to side, toward and away, hand and arm applying a variety of forces depending on the technique used to write or draw. It’s a level of engagement on par with sculpting or painting—the effort is physical, concentrated and the feedback is immediate.

Whiteboards don’t really allow for the same interaction. The scale is similar, but they are too slick and glossy to provide satisfying resistance—unless you count the resistance provided by a dried-out dry erase marker. The range of techniques is limited: just try to smudge a line on a whiteboard! It’s too fragile; it simply vanishes. And even photographing a whiteboard to capture the final result can be problematic because of glare and contrast.

We need more blackboards and lots of chalk—we can do better thinking with them.

Do the math.