Monday, March 14, 2011

Pi Day

Today, March 14th, is Pi Day. No, that's not a typo. It is Pi day, as in 3.14159... you get the idea. The first Pi Day celebration was held at the San Francisco Exploratorium in 1988.

What is pi anyway? I'm sure you remember it from math in some formula you memorized, but do you really know what it is? Pi represents the relationship between a circle’s diameter (its width) and its circumference (the distance around the circle). Pi is always the same number, no matter the circle you use to compute it. In school we generally approximate pi to 3.14 in school, but professionals often use more decimal places and extend the number to 3.14159.

One activity I loved doing with students was to ask them to bring in a can and lid that would soon be recycled. I always brought in a few extras so that there would be a variety of sizes. Each student was given a lid and directed to measure the diameter and circumference. Students then divided the circumference by the diameter. We recorded the results on the overhead and discussed them. Most were amazed to find that the results were nearly the same, allowing for some margin of error in measurement. This is a quick and fun and provides a meaningful way to introduce the concept of pi.

Are you doing anything special for Pi Day? I hope you'll be celebrating in some small way. Perhaps you could make a pi necklace. Since any day is a good day for poetry, you could try reading some pi poems. If you're looking for more ideas, visit the Exploratorium pi site or try this middle school math newsletter.


  1. My daughter brought a frozen pie to school to share and competed in a pi contest where you tried to recite as many digits as you could past the decimal. She told me the winner in her class recited more than 100 digits past the decimal.

  2. For our denouement
    My circular troupe
    will attempt to complete
    A loop-da-loop.

    In order for us
    to finish this chore
    we each must round up
    in 3.14

  3. I had no idea it was Pi Day until I read your post. Thanks so much for the inspiration. I had a great time writing this post and my Limerick Ode To Pi Day.

  4. I am pi

    Diameters just aren’t your bag?
    You probably won't dig me.
    Could live without circumferences?
    Don't take me out for coffee.
    You think that Euclid guy's a snore?
    Well you're in luck, he's dead.
    Can't bother with geometry?
    Just bake a pie instead.

    Copyright (c) 2011 Carolyn Arcabascio, all rights reserved.