Pi Day — A Celebration Of Math And Pie!

March 14 is Pi Day in the US (Credit: Flickr/ Public Domain)

A holiday dedicated to a math constant might not sound thrilling. But Pi ("π") Day, celebrated annually in the US on March 14 (3/14), is an exception. The festivities usually start with pi-themed activities to celebrate the ratio of a circle’s circumference to its diameter (approximately 3.14). But they almost always end with a delicious slice of pie.

The fun tradition was started by Larry Shaw, a physicist at San Francisco's Exploratorium Museum. On March 14, 1988, he convinced colleagues to celebrate pi by walking around a circular space and eating fruit pies. The event was such a hit that the museum made Pi Day an annual celebration. Visitors took part in pi-themed activities and enjoyed savory pies. As word spread, schools, libraries, and universities across the US joined in. In 2009, Congress officially designated March 14 as National Pi Day.

Celebrations

Today, Pi Day is observed in many creative ways. The Massachusetts Institute of Technology (MIT) marks the occasion by sending acceptance letters to prospective students. However, instead of 3:14 PM EST, they send them at 6:28 PM. The number, twice the value of pi, is called tau. It is believed to be more reliable than pi, and even has its own special day on June 28.

Another unique tradition is observed by female television meteorologists, who wear purple on Pi Day. The "Dress for STEM" movement aims to inspire more girls to pursue careers in science, technology, engineering, and math.

In addition, bakeries and restaurants offer discounts on pies and pizzas, schools host pi recitation contests, and math enthusiasts gather for circle-themed games. Some even challenge themselves to eat exactly 3.14 slices of pie.

March 14 is also Albert Einstein's birthday. The connection is especially meaningful in Princeton, New Jersey. This is where Einstein spent the last two decades of his life. The city marks both occasions with many events. They include pie-eating contests and an Einstein look-alike competition. The festivities also feature science-themed tours and lectures honoring the famous physicist's contributions.

The origin of pi

Albert Einstein was born on March 14 (Credit: Ochoa54/ CC-BY-SA-2.0/ Wikipedia.org)

Pi Day celebrations are fairly new, but the mathematical constant has been known for thousands of years. The Babylonians used it 4,000 years ago to determine the area of a circle. They gave pi a value of 3. The ancient Egyptians refined this estimate around 1650 BC, assigning pi a value of 3.165.

Archimedes of Syracuse (287-212 BC) was the first to calculate the constant mathematically. He gave pi a range of between 3 1/7 and 3 10/71. Today, with advanced computing, pi has been calculated to over 62 trillion digits. But for most, 3.14 (or a slice of pie) is enough to celebrate!