Calculation indicates: Too. Damned. Close.

There are 18,000 stories on the masked campus; here’s one of mine. We’d love to hear yours.

As a blind person, I am confident that I can negotiate my way safely around new hand-washing installations, along one-way hallways, and through the plexiglass mazes that are popping up in our classrooms. Twenty years of making my way through (sometimes unmarked) campus construction zones have had their effect.

I am also confident (although I don’t in any way think this is practical or sufficient) that I can wipe down surfaces in my classroom and do a fair job policing my students’ mask use in class. I did, after all, raise two children; the skill set is both analogous and scalable.

What I wonder about is maintaining six-foot social distancing in a context where—face it—most people are not paying attention.

Here’s the math:

I use a 52-inch-long white cane. It is positioned in front of me when I am moving, but I don’t hold it at the tip of the handle; there is quite a bit of overlap between my hand/arm and the top of the cane; then there’s the rest of my arm. I hold the cane at an angle so that there is a (reasonably) straight line from my right shoulder down my arm to the cane tip resting on the floor. The total distance is approximately 74 inches, and it forms the hypotenuse of a right triangle. Let’s be traditional, and call that line segment C.

The vertical leg of the triangle is the distance from my right shoulder to the ground, 54 inches. Let’s call that B.

At question here, then, is the length of the line segment which extends from my foot to the tip of the cane—the distance I am standing from you when my cane tip hits your foot. Call that “FootSmackDistance.”

Thanks to the good Mr. Pythagoras, we know that there is a computable relationship among these three distances, so that if we know two of them, we can calculate the third. And, thanks to Mohammed Al-Khwarizmi, it’s easy enough to work the formula.

C2 = B2 + FootSmackDistance2


74 2 = 542 + FootSmackDistance 2

Now, there are a lot of places for wiggle and adjustment. I don’t, for example, always hold my arm straight, and my cane will not reliably tap you on the heel as opposed to the front of your foot. Also, I might be leaning slightly forward or backward (tense from having to do geometry all day), or you might lean in one direction or the other as a result of being unexpectedly struck on the foot by a blind person you didn’t see coming.

But, roughly, if my cane taps your foot, we are standing …

50 inches apart; that’s four feet two inches.

Too. Damned. Close.

We use an average stride length of 26 inches for women (and 30 inches for men) when setting up pedometers, and my stride is slightly shorter than this, around 23 inches.

So the take-home is …

If my cane smacks your shoe, we should probably both take a good, solid pace back to ensure a social distance of six feet. And this we shall do, by my calculations, about 50,000 times over the next 100 days.