March 14 is Pi Day because March is the third month, and with 14 as the day, we get the first three digits of pi - **3.14**! On Pi Day, nerds, geeks, and mildly interested geometry students alike come together and wear pi-themed clothing, read pi-themed books and watch pi-themed movies, all the while eating pi-themed pie.

Pi is an irrational number that approximately equals 3.14. It is the number you get if you divide the circumference of any circle by its diameter, and it's the same for all circles, no matter their size. You can estimate pi for yourself by taking some circular things like the tops of jars or round plates and measuring their diameter and their circumference. Then divide the circumference by the diameter, You should get an answer something like 3.14. It should be the same every time (unless you measured wrong). In other words,

**π** is the number of times a circle’s diameter will fit around its circumference

Actually, 3.14 is only approximately equal to pi. That's because pi is an irrational number. That means that when you write pi as a decimal it goes on forever and ever, never ending. (It is infinite.) Also, no number pattern ever repeats itself.

Usually in math, we write pi with the Greek letter

**π**, which is the letter "p" in Greek. You pronounce it "pie", like the pie you eat for dessert. It is called pi because

**π** is the first letter of the Greek word "perimetros" or perimeter. What is interesting is that in the Greek alphabet,

**π** (piwas) is the sixteenth letter; likewise, in the English alphabet, the letter "p" is also the sixteenth letter.

But hold your horses! The fascination with pi isn't restricted to just mathematicians and scientists. Pi has a special place in popular culture, thanks to its frequency in mathematical formulas and its mysterious nature. Even T.V. shows, books, and movies can’t help but mention

**π**.

For example, pi gets mentioned in a scene from

*Twilight*, in which vampire-boy Robert Pattinson recites the square root of pi. In an episode of the Simpsons, two young girls at a school for the gifted play patty-cake and say

*“Cross my heart and hope to die, here’s the digits that make pi, 3. 1415926535897932384…” *
Yep, whether you like it or not, pi is everywhere. Here are a few more places it has popped up:

- The main character in the award-winning novel (and 2012 film)
*Life of Pi *nicknames himself after **π**.
- A circular room in the Palais de la Découverte science museum in Paris is called the pi room. The room has 707 digits of pi inscribed on its wall. (The value of pi has now been calculated to more than two trillion digits.)
- In an episode of
*Star Trek: The Original Series*, Spock commands an evil computer to compute **π **to the last digit which it cannot do because, as Spock explains, *“The value of pi is a transcendental figure without resolution.”*
- Pi is the secret code in Alfred Hitchcock’s
*Torn Curtain* and in *The Net *starring Sandra Bullock.

Here is more arbitrary information related to pi that I found interesting.

- If you were to print one billion decimal values of pi in an ordinary font, it would stretch from New York City to Kansas (where I live).
- 3.14 backwards looks like PIE.
*"I prefer pi"* is a palindrome. (read the same backwards as forwards)
- Albert Einstein was born on Pi Day (March 14) in 1879.

And let's finish this post with a couple of **π** jokes.

If you divide the circumference of the sun by its diameter, what will you have?

**Pi in the sky!**
What do you get if you divide the circumference of a jack-o'-lantern by its diameter?

**Pumpkin pi! **

On Pinterest, I have a board devoted to pi called

"Life of Pi." If you go there, you will find many cartoons, jokes and ideas to use for pi day. And to add to the fun, go to the website entitled “

The Pi-Search Page” to find your birthday written with the digits of pi.

By the way, notice my "handle" of Sci__pi__. The **Sci** is for science (what my husband teaches) and the **pi** is for **π **because I teach math.