## In Praise of Pi(e)

*How I need a drink, alcoholic in nature, after the heavy lectures involving quantum mechanics.*

If you’ve read that sentence before, you’re a better geek than I.

So-called Pi Day, celebrated on March 14, is almost upon us. That sentence is the best-known example of a form of writing called, appropriately, Pi-lish, which is designed to help you remember the digits of the number pi. If you count the letters of each word in that sentence, you’ll have recited pi out to 12 decimal places.

Pi, of course, is the so-called circle constant, represented by the Greek letter of the same name. It’s defined as the circumference of any circle divided by its diameter, or roughly 3.14159.

Pi appears repeatedly throughout geometry, but also, says Ron Hipschman, a scientist at San Francisco’s Exploratorium, “anytime you have cycles, frequencies, or anything that’s rotating. It’s in tons of different places.”

Pi has been calculated to 10 trillion digits, and counting.

In 1988, the Exploratorium’s Larry Shaw, a physicist, thought pi deserved a holiday of its own. So on March 14 (3/14) he put out some pie for the staff. The next year, some museum visitors noticed the pie and asked what was going on. And that’s how Pi Day was born.

Now, hundreds of people visit the Exploratorium to celebrate, and Pi Day has spread around the world. Even bakeries are starting to get into the act, selling mini-pies for $3.14 or pies that can be eaten in a bit more than three bites.

The increasing celebrity of pi has, not surprisingly, attracted a corresponding group of naysayers. Bob Palais, a professor of mathematics at the University of Utah, argues in an article called "Pi is wrong," that really, we should be celebrating tau -- the circumference of a circle divided by its radius -- instead of pi.

Tau is simply twice pi, but this is emphatically not the point, says Michael Hartl, a former physics instructor at Caltech turned author and entrepreneur, and formulator of The Tau Manifesto. "Because it involves dividing by the diameter, pi isn't the most natural choice for the circle constant," says Hartl. "It got chosen originally because it’s easier to measure a diameter than a radius."

Albert Einstein may have been born on Pi Day, but Hartl points out that Maria Goeppert-Mayer, the only female theoretical physicist to ever win the Nobel prize, was born on June 28 -- or, as he prefers, Tau Day. Tau is not, unfortunately, a homonym for a delicious dessert with a flaky crust. Advocates for tau use the symbol for the similar-sounding tao as their logo.

**Making the most of pi(e)**

Other than eating pie and possibly running around in circles, I didn’t think there was much more you could do to celebrate pi. How wrong I was. Shaw, now retired and known as the Prince of Pi, returns to the Exploratorium each year to lead its pi procession, in which each person carries a digit of the never-ending pi. The parade begins at 1:59 pm, is accompanied by music composed to pi, and ends by circling the museum’s pi shrine -- you guessed it -- 3.14 times. Then everyone sings happy birthday to Einstein.

If this sounds hopelessly silly to you, I’m not going to argue. But we live in such a math-challenged society that it’s hard not to find it charming and even sort of fun. So when Lori Lambertson, who works at the museum’s teacher institute, tells me that Pi Day also includes the reading of pi-lish and piku (haiku on the topic of pi) I guess I shouldn’t have been surprised. Turns out, that was nothing. “People show up in their favorite pi t-shirts,” Lambertson says. “A woman made a skirt with pi symbols all over it. There’s a couple who named their baby pi.”

Even if you have no particular interest in pi, Pi Day will still be a fun day to visit the Exploratorium if you’re in San Francisco. On Pi Day, admission is always free. And yes, there will be free pie. -- *Kimberly Weisul*

*By the way, if you're looking for an easy pie recipe, try this one for apple pie from Kids Cooking at About.com. It calls for pre-made pie crusts, which is why it's easy! Enjoy.*

March 13, 2014

If you liked this story, you might also like:

My Hovercraft is Full of Eels, and Other Useful Phrases

Use the Cut! Play it Like They Do in Little League

Got a story idea? Think we're fabulous? Email us at more [at] onethingnew [dot] com, follow us on twitter, or visit us on facebook. And help us spread the word. We appreciate your help in getting the word out about what we're up to!