By Sean Greene

A pi pie. (Paul Smith/Flickr)
A pi pie. (Paul Smith/Flickr)

The biggest math- and pastry-themed party in San Francisco is Pi Day at the Exploratorium.

They’ll have the Pi Procession around the Pi Shrine, pi lectures — and actual pie.

Ron Hipschman of the Exploratorium said Pi Day got started in 1988 when Larry Shaw, the “Prince of Pi” and now-retired physicist at the museum, realized March 14 was the ideal day to celebrate the never-ending number. The 25th Annual Pi Day will serve as a pre-party to the April 17 opening of the Exploratorium at its new location on Pier 15.
“(Pi Day has) become kind of a geek holiday so it’s now celebrated all over the world in classrooms and universities, all kinds of places,” Hipschman said.

The festivities will get rolling tomorrow at 1:59 p.m.–so date and time match the first five values of pi — with the “Pi Procession.”

Pi partiers will get a yardstick mounted to a pie plate, each with a single digit of pi on it. Then all 500 of them will line up in pi-order and parade down the Embarcadero to the “Pi Shrine.”

“We have to circumambulate the Pi Shrine 3.14 times while singing ‘Happy Birthday’ to Einstein whose birthday it is on Pi Day,” Hipschman said. “So we celebrate Einstein’s birthday and Pi Day all at once.”

The Pi Shrine is a brass plate, about a foot in diameter, with the first 108 digits of pi spiraling inward until the numbers are too small to see.

“That’s not a significant number, it’s just that’s how many we could fit,” Hipschman said.

Other pi-related activities include: Joe Forte of Pasquale’s Pizzeria tossing pizza dough, quirky pi talks from Hipschman and Lori Lambertson, and measuring the circumference and diameter of various circular objects — since pi is the ratio of a circle’s circumference to its diameter.

“Pi  has been computed now to 10 trillion digits. That’s a lot of digits,” Hipschman said. “You don’t need that many digits of course, you only need like 39 decimal places of pi to compute the volume of the universe, plus or minus the volume of a hydrogen atom.”

And if you’re really feeling the holiday spirit, you could learn the digits of pi. The practice is called piphilology, and Hipschman said there have been claims of 100,000 digits being memorized.

“I’m not even close to 100 digits myself,” he said.

To help you remember, try learning a “piem,” a pi poem in which the length of each word is a digit of pi. Hipschman demonstrated: “How I need a drink alcoholic in nature after the heavy lectures involving quantum mechanics.”

“We also have ‘paikus.’ Which are haikus that contain material about pi. And of course, I guess you could technically combine the two and have a piem that is a paiku.”

Hipschman’s example: “Can I know a cycle / according to nature round / and never complete?”

“Of course, there’s pi limericks as well.”

Pi Day? Here Are 3.14159265359 Reasons to Celebrate in San Francisco 14 March,2013Molly Samuel
  • they’re all being irrational 🙂

  • Ronald Paul Gavisk

    4 – 6/7 – 1/791 = 3. 14159292 (BY: Ronald Paul Gavisk; Author; Inventor, Electronic Engineer, Designer! @Copy-Right 2003!

  • John Gabriel

    Pi – just another magnitude that refuses to be measured. Pi is not a number, it is an incommensurable magnitude.

  • just some joker

    What a half-as*ed celebration…. Why is everyone so hung up on half a circle? I mean really – did they serve half pies or half pizzas!? Tau’s day shall come!

    • John Gabriel

      For the same reason they are hung up on half a diameter?

      Tau is probably better to use, but there is no fundamental difference between the idea: a magnitude resulting from a special relationship between the circumference and radius of a circle.

  • Sir_Spamalot

    An interesting way to find the value of PI can be found at

    Very visual, as it show how when a regular polygon has many sides it becomes an approximation of a circle. By unfolding the polygon you can measure it against a ruler. This gives the value of 2π

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