March 14th, 3/14. This is one of the most exciting days of the year for mathematicians, scientists, and foodies alike. On this day, mathematicians celebrate one of the most important numerical constants, while businesses offer excellent deals on pies and pizzas.

Widely known in the math community as the ratio of the circumference to the diameter of a circle, Pi is a mathematical constant that is essential to explaining key phenomena in many fields of science, including planetary science, physics, and engineering. 

Although commonly written as 3.14, Pi is actually an irrational number, meaning it is a never-ending, non-repeating decimal. The first accurate approximation of Pi was made in 250 BC by Greek mathematician Archimedes. 

Over time, scientists around the world have continued to add digits to Pi, still searching for the next digits to add onto this never-ending number. Currently, the longest approximation (according to Guinness World Records) is over 62 trillion digits, calculated by a team at the University of Applied Sciences in Switzerland.

Pi Day started in 1988 as a humble celebration of the mathematical constant by Larry Shaw, a physicist at San Francisco’s Exploratorium. The first celebration involved Exploratorium staff marching about a circular area of the museum while enjoying a feast of pies. 

However, the celebration soon received widespread attention and was declared a national holiday by the US House of Representatives in 2009. This year marks the 35th celebration of Pi Day at the Exploratorium.

Today, to celebrate Pi Day, many schools discuss the importance of Pi and people consume a variety of pies to celebrate an important concept of mathematics. The celebration has expanded to now include pizza, which is often also referred to as “pie.” Many businesses offer discounts on their products; some go so far as pricing their food at $3.14.

Pi Day is a fun way to celebrate science and math, which are often viewed as complicated and tedious, and reminds people of the importance of STEM while also enjoying a sweet (or savory!) treat to commemorate this event.