Pi Day: A Celebration of Mathematics and Pie

Each year on March 14, math enthusiasts around the world celebrate Pi Day, honoring the mathematical constant π (pi). Represented by the Greek letter “π,” pi signifies the ratio of a circle’s circumference to its diameter, approximately equal to 3.14159, though it continues infinitely without repeating.

The Significance of March 14th

The date, 3/14, was chosen given that it corresponds to the first three digits of pi – 3.14. The tradition began in 1988 at the Exploratorium in San Francisco, founded by Larry Shaw, an employee of the science museum Exploratorium. Pi Day has since grown into an international holiday, celebrated both in person and online.

Beyond the Numbers: Celebrating with Pie

While Pi Day is a celebration of mathematical curiosity, it also provides a playful opportunity to enjoy… pie! The homonym connection makes indulging in a slice of pie a popular tradition alongside mathematical discussions and competitions, such as pi recitation contests. Pi Day is an annual opportunity for math enthusiasts to recite the infinite digits of Pi, talk to their friends about math, and eat pie.

A Brief History of Pi

Pi has been calculated to over 50 trillion digits beyond its decimal point Pi Day. As an irrational and transcendental number, it continues infinitely without repetition or pattern. Throughout history, mathematicians like Archimedes, Liu Hui, Zu Chongzhi, and Srinivasa Ramanujan have contributed to our understanding and calculation of pi.

Rhubarb Hand Pies: A Pi Day Treat

To celebrate, consider baking a pie! Here’s a recipe for Rhubarb Hand Pies:

Rhubarb Hand Pies Ingredients (Makes 6 pies)

• ¾ pound fresh rhubarb, trimmed and cut into ½-inch pieces
• ⅓ cup packed dark brown sugar
• 1 teaspoon lemon zest
• 1 teaspoon fresh lemon juice
• ¼ teaspoon ground ginger
• ¼ teaspoon kosher salt
• 1 teaspoon pure vanilla extract
• 1 pie crust (2 discs), homemade or store-bought
• 1 large egg, beaten
• ½ teaspoon turbinado sugar (for sprinkling)

All-Purpose Pie Crust Ingredients (Makes two 9-inch pie crusts)

• 2 ¼ cups unbleached all-purpose flour
• 1 teaspoon kosher salt
• 1 cup ice-cold unsalted butter, cut into pieces
• 6 to 8 Tablespoons of ice water

Rhubarb Hand Pies Directions

1. Combine rhubarb, brown sugar, lemon zest and juice, ginger, salt, and ¼ cup water in a saucepan. Bring to a boil, then reduce heat and simmer for 12-15 minutes, until thickened. Remove from heat, stir in vanilla, and cool.
2. Preheat oven to 400°F. Combine beaten egg with 1 tablespoon water for egg wash.
3. Roll out one disc of dough to ⅛ inch thick. Use a 6-inch biscuit cutter to stamp out 3 circles. Brush edges with egg wash, spoon 2 tablespoons of rhubarb mixture onto one half of each circle.
4. Fold unfilled side over filling and crimp edges with a fork. Brush tops with egg wash, make slits for ventilation, and sprinkle with turbinado sugar. Refrigerate.
5. Repeat with the second disc of dough and remaining filling.
6. Bake for 15-18 minutes, or until golden brown and bubbling. Cool on a baking sheet for 10 minutes before transferring to a wire rack.

Pi Day Around the World

Originally celebrated in the United States, Pi Day has expanded globally. In 2009, the United States House of Representatives officially recognized Pi Day. In 2019, UNESCO designated March 14th as the International Day of Mathematics Pi Day, further solidifying its importance as a celebration of mathematical curiosity and achievement.