Every year on March 14^{th}, talk turns to pie – oops, we mean pi! (not that we don’t love both sweet and savory pies!)

Why is this year so different than other years? The answer is based in the definition of pi!

Pi, the first letter of the Greek word perimetros or perimeter, refers to the mathematical calculation of the circumference of a circle divided by its diameter, which is approximately 3.14159.

Play with pi and try it yourself!

Start with a piece of string and a circle. To find the circumference, put the end of the string on a point along the circle and measure all the way around the outside with the string until you come back to the starting point. Cut the string so it is exactly the size of the outside of your circle. This is the circumference. Next, take the string and measure straight from one point across the middle of the circle directly from one side to the other. This is the diameter. How many times can you use the circumference string to go back and forth along the diameter with your circumference string? [You should be able to do it three times with just a little bit left over — like, oh, about .141592654!]

What if the circle you use is bigger? What if it is smaller? Give it a try!

A fascinating thing about pi, is that when you write it out as a decimal, it goes on forever… never ending and without a repeating pattern!

So, back to the question about why this year is so special. If you look at pi and follow it out to 9 places past the decimal, you can pinpoint the celebration moment at March 14^{th}, 2015 at 9:26:54 0r 3/14/15 9:26:54!

If you want to see what pi looks like out to a million places… you can find it here: http://www.piday.org/million/

Learn more about the fun of pi from our friends at http://scienceforkids.kidipede.com/math/geometry/pi.htm