Who Wants Pi?

Today is Pi Day, and not the fruity, creamy or custardy kind with the sweet filling and tender crust. Nope, it’s the math kind of pi, the 3.14159… I don’t know the rest because I never memorized past the 9!

The Greek symbol π, or Pi, represents that elusive number that goes on forever, the quotient found by dividing the circumference of a circle (the distance around it) by its diameter (the distance across its middle). Pi Day, March 14 (3/14), was founded in 1988 by Larry Shaw, a curator at San Francisco’s Exploratorium Museum of Science, Art, and Human Perception. Mr. Shaw passed away last fall, but his special day will likely live on as long as the numbers after the decimal point in pi.


By Matman from Lublin – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14598097

Pi is primarily known for its usefulness for determining a circle’s circumference and the area of a circle, cylinder, cone, or sphere, but pi has much, much more to offer than your average decimal. In my early statistics classes, I vaguely remember using pi to figure out distributions, which in turn were used to figure out probabilities, or the likelihood of an occurrence. Knowing the likelihood of a future event is useful information to have. For example, I would like to know the odds of one of my sons calling me this month, or the chances that I’ll get around to mowing the lawn this year or finishing this column by the deadline. Pi can help with that.

Pi is also featured in the Fourier transform, a formula for converting signals to frequency spectrums. It’s used in cell phone and medical imaging technology, for analyzing DNA sequences, and lots of other places. You should Google or YouTube it for a thorough explanation, or if you have a teenager, ask them. I learned about it in an electronic music class back in the 1970s when I was trying to build a Theremin, a predecessor to modern digital instruments. I never got it to work right, and that was the end of my math (and musical) career.

Pi is also part of the Schrödinger equation, a staple of quantum mechanics. This is the same cat-in-the-box Schrödinger from physics class. Remember that guy? His formula, a differential wave equation, recently enjoyed a galactic comeback across science journals and social media. Apparently, the Schrödinger equation, typically relegated to the lowly study of waves, particles, and “wavicles” at the atomic and subatomic level, explains the warps in all those astronomical spinning space disks we’ve been wondering about for so many years. OK, not all of us have been wondering about the warps. I wasn’t even aware of them until last week. But hey, way to go, pi! We couldn’t have done it without you. By the way, if you want an idea of what a warped disk looks like, get out your “original copy” of Led Zeppelin II, throw it on the turntable, and give it a spin.

Knowing what pi means makes people feel smart, even if it’s the only thing they remember from math class. Most of us finish up geometry and trigonometry, dabble a bit in calculus, and then — unless we start a math-centric major like science, engineering or finance — we move on and forget all about math. But we shouldn’t forget math or take it for granted. And we should never, ever think a mathematical discovery has nothing to do with us.

Math explains a lot whether we care about it or not. When new uses are discovered for numbers — like explaining the lumps and bumps in space disks — we should pay attention and thank our lucky stars there are people who remember and use math all the time. Those kinds of discoveries have a way of trickling down to innovative technologies that affect our daily lives, typically for the better.

I’m not one of those math people, but I salute them, and I never take math for granted. So, on this day, March 14, raise a glass of whatever you’re drinking — to pi! And while you’re staring down at the bottom of your glass, remember: thanks to the power of pi, determining the value of its circumference and the volume of whatever you’re drinking — if you’re inclined to do the math — is possible!

This blog first appeared as a column in the March 14, 2018, Woodmen Edition of the Gazette Community News.

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