Covid math you learned in elementary school

The three major Covid-19 mitigations available to “normal folks” have clearly become highly politicized. The frustrating thing here is that all three are based on science and mathematics principles that you likely learned in elementary school, but have either been forgotten or have been overridden by anti-science political cultism.

So, squeeze yourself back into that 5th grade desk and let’s see what we can remember.

Soap, surface tension and fractions

We have been using a lot of antibacterial soaps and hand sanitizers, but just plain old soap has some amazing properties, and can really do most of the job here. I remember this simple science experiment from my elementary school years. It was likely from Don Herbert, aka “Mr Wizard,” the prototype for Bill Nye the Science Guy, on black-and-white television. You can float a paper clip on top of a class of water because the surface tension of water holds it up. Essentially, tap water is not “wet enough.” But place one drop of soap anywhere near the paper clip it will quickly sink. Soap “makes water wetter.”

Oil and dirt on your hands entrap all kinds of bacteria and viruses, and just rinsing with water is insufficient to break the surface tension bonds holding them there. But as the Jarmels sang in 1961, “Just a little bit of soap can wash away the coronavirus” (or something like that – I forget the lyric; check out the Jarmels video below).

In what grade did you learn fractions? Even if that soap washes away just 1/2 of the bad stuff, is that not worth the effort? And if you can hum your way through the entire Jeopardy theme, you can likely raise that fraction to 9/10ths. And that is before the hand sanitizer! Wash your hands!

Social distancing and the inverse-square law

In what grade did you learn how to square a number? Five times five is twenty-five. Six times six is thirty-six. And one times one is one. The inverse-square law applies to hundreds of natural phenomena, from gravity to magnetism to the intensity of light. It says that the power of any of these forces is reduced over distance by one divided by the square of the distance.

And so, a magnet is 1/25th as powerful at five inches than it is at one inch (magnets being another Mr. Wizard episode, as I recall). Or 1/36th as powerful at six inches. Electrostatic forces work under the same principle, and are related to the surface tension principle above. Water droplets in air, which carry the coronavirus from an infected person, are  heavily impacted by natural electrostatic forces. And so, as Mr. Wizard would say, “What have we learned here, Ricky? Do you prefer one foot, or five feet, or six feet of social distancing?” Do the math.

Back to grade school, at some point you learned that 1/25th is the same as four percent, and 1/36th is less than three percent. Going from 100% to 3% is a huge reduction of risk. Back off, Gus!

Those masks

Mask use has especially enraged Trump cultists, even though he now occasionally wears one himself. Iowa”s Governor Kim Reynolds and Florida’s Governor Ron DeSantis have been especially reluctant to either wear masks in public or to implement masking orders. Walmart is doing a better, though imperfect job than either of these two who fear nasty tweets. Delta Airlines knows the math so well that it will turn that plane around just like your father used to threaten you when you misbehaved in the back seat of the car.

Again, the math here is really simple, even if you don’t have a precise rating on the effectiveness of your particular mask. Timmy, if my mask still allows 50% of my infected water droplets to escape, and your mask only stops 50% of my escaping water droplets, what is the percentage of the infected water droplets that could possibly get into your nose? (Hint: multiply 0.5 times 0.5. There is a calculator on your phone.)

Okay, now stand back five feet away from me in the checkout line (see above). That is 0.5 times 0.5 times 0.04. I’ll give you this one: it is 0.01, or one percent, or one out of one-hundred. That is some pretty good mitigation right there, even with imperfect measures. With better masks and more distancing, I soon need more zeros after the decimal point.

The New York Times recently published an article showing that even riding the subway can be safe, based on the experience of several Far East countries with universal mask-wearing and good cleaning, even if social distancing gets problematic at times. This is the “Swiss cheese” approach; overlay a few layers of Swiss cheese, even with the holes, and you can still likely plug a water leak.

This is just fifth grade math and science, folks. We can reduce the statistical probabilities of contracting this virus from “drunk driver odds” down to “safe driver odds” if we really want to get the economy going again.

Here is “Just a little bit of Soap” by the Jarmels:


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