Photo: Cookie Ladron de Guevara (Shutterstock)
On March 14, the more nerdy side of humanity celebrates Pi Day, a holiday that “celebrates the irrational, transcendent, and infinite ratio that helps describe circles of all sizes.” Pi is the ratio of a circle’s circumference to its diameter. This results in a number starting at 3.14, regardless of the size of the circle. Take it? It’s 3.14 or March 14th.
The first Pi Day was announced in 1988 by Larry Shaw, an associate at the San Francisco Research Center. Pi Day has since been recognized by Congress, and the 40th General Conference of UNESCO proclaimed March 14 as “International Mathematics Day” in 2019. This holiday is often celebrated by walking in circles or eating cake and other round foods.
But it should also be a day of learning, for nerdy adults and kids alike. So here are a few Pi facts to eat with pie and share with curious kids and loved ones in honor of the day.
Mind Blowing Facts About Pi and Pi Day
- We usually approximate pi with numbers like 3.14 or 3.14159, but the series of numbers to the right of the decimal point actually goes on forever—we just don’t write them all down because we don’t have infinity. Pi is an infinite irrational number that never falls into a repeating pattern.
- While pi is infinite, from a practical standpoint, we really only need a few digits for accurate measurements. NASA only uses 15 or 16 digits for calculations that are accurate enough for our space program.
- If you were to calculate the circumference of a circle the size of the entire known universe, down to the diameter of a hydrogen atom, you would only need 39 or 40 digits of pi.
- Before the advent of computers, calculating the digits of pi was difficult and time-consuming. In 480, Zu Chongzhi calculated the first seven digits of pi. Over a hundred years later, Adrian van Roomen brought the number to 20 digits.
- Beginning in 1853, the British mathematician William Shanks began to work on this problem. 20 years later, he calculated pi to 707 decimal places. But Shanks made a mistake in the 527th digit, so all subsequent numbers were wrong.
- The most accurate calculated value of pi is 62.8 trillion decimal places. (Come on, computers!)
- Rajveer Meena holds the world record for memorizing the most decimal places of pi. He is exactly remembered 70,000 decimal places in 10 hours.
- Super Pi Day was celebrated on March 14, 2015 because the date was 03/14/15, adding two more digits of Pi. The show’s actual stops occurred a few minutes before 9:30 AM and PM when the first 10 digits of Pi were introduced: 03/14/15 9:26:53 AM.
- There is a style of writing based on Pi. In Pilish, the lengths of successive words are the digits of pi. If you count one letter in each word in this sentence: “How I want to drink, of an alcoholic nature, after heavy lectures on quantum mechanics!” This is 3.14159265358979. Mike Keith wrote an entire novel, No Wake, in Pilisha.
- Some mathematicians think we should celebrate “Tau Day” instead of Pi Day. They claim that tau (twice pi) is the best circle constant. Tau Day is celebrated on June 28th.
- Pi is named after the Greek letter “p” and not after a pie, a dessert treat. But you can use pi to find the volume of a pie, or you can use pie to calculate pi.
- If you write the first three digits of pi backwards (3.14), it will look like PIE.