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Pi Day March 14, 2009: Activities for Math Lovers in Honor of π

by Tina Kells | March 12, 2009 at 11:52 am

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Pi Day on March 14, 2009 is one of two days earmarked by math lovers to officially honor the mathematical constant called Pi (π). Pi Day (March 14) and Pi Approximation Day (July 22) are based on the numerical value associated with Pi, π = 3.1415926...

Pi Day is sometimes further reduced to Pi Minute which is marked at 1:59pm local time on March 14. Traditional Pi Day activities include lots of eating: eating pizza pies, eating fruit pies, and eating any other circular food.

Pi Day was invented by physicist Larry Shaw and the first Pi Day celebration was held at the San Francisco Exploratorium in 1988.

In 2009 the US Congress officially recognized March 14 as Pi Day in the United States. The alternate Pi Day date of July 22, representing is the ancient world's approximation of Pi (π) was not officially acknowledged.

The first Pi Day celebration was held at the San Francisco Exploratorium in 1988, with staff and public marching around one of its circular spaces, and then consuming fruit pies; the museum has since added pizza pies to its Pi Day menu.[1] The founder of Pi Day was Larry Shaw,[2] a now retired physicist at the Exploratorium who still helps out with the celebrations.

The Massachusetts Institute of Technology often mails out its acceptance letters to be delivered to prospective students on Pi Day.[3]

Some also celebrate Pi Approximation Day in addition to Pi Day, which can fall on any of several dates:

April 26: The Earth has traveled two radians of its orbit by this day (April 25th in leap years); thus the entire orbit divided by the distance traveled equals pi

July 22: 22/7 in the more common day/month date format, an ancient approximation of pi

November 10: The 314th day of the year (November 9 in leap years)

December 21, 1:13 p.m.: The 355th day of the year (December 20 in leap years), celebrated at 1:13 for the Chinese approximation 355/113

On Pi Day, 2004, Daniel Tammet calculated and recited 22,514 decimal digits of pi.[4]

Albert Einstein was born on Pi Day, 1879.

The U.S. Congress recognized March 14, 2009 as "National Pi Day".[1]

Most people know Pi π by its simplist expression of 3.14 but the number has been calculated to more than a trillion digits. Pi π represents the ratio for the circumference of a circle as compared to its diameter and was first used in 1706 by William Jones.

Pi π is an irrational number, meaning it can not be written as a simple fraction but can only be expressed as an infinite, nonrepeating decimal. Two well known examples of an irrational number include Pi π and the sqaure root of 2.

Other than eating all varieties of pie, Pi Day is honored by math teachers with different activities designed to teach students about the value of Pi π. PiDay.org has an excellent ongoing collaborative list of Pi Day activities for students.

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Barry Artiste

at 18:35 on March 12th, 2009

MMMMMMMMMMMMMM Pie!!!!!!!

Droooooooooooooollllllllllllll, cake are square though, just as good!

Jordan Yerman

at 21:41 on March 13th, 2009

TGIP.

Pythiian1

at 10:44 on March 14th, 2009

Pi Day :-)

wiredgnome

at 20:50 on March 14th, 2009

Cool! Maybe we will all catch on and local bakeries will start to sell pi-symbol parties and goods. It would be an mathematically-stimulating treat! :-)

Jeremy M (not verified)

at 06:47 on June 6th, 2009

Go PI Day!

3.14159265358979323846264338327950288419716939937510

58209749445923078164062862089986280348253421170679

82148086513282306647093844609550582231725359408128

48111745028410270193852110555964462294895493038196

44288109756659334461284756482337867831652712019091

45648566923460348610454326648213393607260249141273

72458700660631558817488152092096282925409171536436

78925903600113305305488204665213841469519415116094

33057270365759591953092186117381932611793105118548

07446237996274956735188575272489122793818301194912

98336733624406566430860213949463952247371907021798

60943702770539217176293176752384674818467669405132

00056812714526356082778577134275778960917363717872

14684409012249534301465495853710507922796892589235

42019956112129021960864034418159813629774771309960

51870721134999999837297804995105973173281609631859

50244594553469083026425223082533446850352619311881

71010003137838752886587533208381420617177669147303

59825349042875546873115956286388235378759375195778

18577805321712268066130019278766111959092164201989

Click Here for pi to 1 million. (Only if you are obsessed)

Jacky Majorenos (not verified)

at 15:26 on June 25th, 2009

Oh i never heard about Pi Day. Nice to heqar about that guys. 3.1416 I am not really good in math, non Math lover to be considered in the school. But Math is everything we need.

jalismak

at 03:54 on July 2nd, 2009

I remember this day. I was on Sheffield and one mathematic teacher give us an assignment for the Pi day . I made a wonderful Pi poster with the historical line of the calculation of new decimals!