In mid-March, math enthusiasts and dessert lovers alike come together to celebrate the most famous irrational number—pi. March 14, also known as Pi Day, has become an international event that blends the wonders of math with fun, community, and most importantly, pie. But how did the annual celebration of this infinite number come to be?
To learn about the quirky origins of Pi Day, it is crucial to understand the origins of the mathematical pi itself. Pi—the representation of the Greek letter π—is the ratio of a circle’s circumference to its diameter, and it is essential for many calculations in math, engineering, physics, construction, and even space exploration. The concept of pi has been around for thousands of years, dating back to ancient civilizations such as Babylonia. However, the earliest recorded use of the symbol π came centuries later when Welsh mathematician William Jones used it in his 1706 work Synopsis Palmariorum Matheseos. Jones’s notation was not immediately adopted by other mathematicians, but in 1748, Swiss polymath Leonhard Euler helped popularize the symbol by using it in his book, Introduction in Analysin Infinitorum.
The first Pi Day celebration took place on March 14, 1988 at the Exploratorium in San Francisco, thanks to physicist Larry Shaw. Shaw found a link between the date March 14—written as 3/14 in many parts of the world—and the first three digits of pi (3.14), which inspired him to host an event at the museum to celebrate the special coincidence. The staff and public that gathered there ate fruit pies and paraded in circles, and Pi Day was born. The celebration became an annual tradition at the Exploratorium, and it soon grew vastly in popularity. In 2009, the US House of Representatives passed legislation to make Pi Day an official national holiday.
Since “pi” and “pie” are homophones in English, many people take this holiday as an opportunity to eat pies in celebration, just as Larry Shaw did. Many bakeries offer discounts and deals for their pies on Pi Day, and some companies even host pie-eating contests. As the term “pizza pie” is used in the northeastern United States, pizza is also commonly eaten to celebrate. The circular nature of both pie and pizza makes these foods ever the more perfect dishes to celebrate pi.
In 2015, Pi Day fanatics had a special treat. Celebrations took place at 9:26:53 A.M., the numerical date and time together representing the first ten digits of pi, 3.141592653. Additionally, the Massachusetts Institute of Technology (MIT) often releases their application decision letters on Pi Day at 6:28 P.M., representing 2π or tau. Interestingly, some of the most famous scientists in the world happen to have a connection to Pi Day. Albert Einstein was born on March 14 in 1879, while Stephen Hawking died on March 14 in 2018.
Today, Pi Day is celebrated worldwide, with people from all walks of life joining in on the fun. From classrooms filled with students learning about circles to restaurants selling all kinds of pies, the celebration continues to inspire people to appreciate the important role math has in the world. Whether you are a math whiz or someone who just likes a good slice of pie, Pi Day serves as a reminder to all that sometimes the most irrational things are the infinitely most fun to celebrate.
