## Wednesday, March 13, 2013

### Pi Day for Some but not All

So it's Pi Day tomorrow in all the parts of the world where the date is written in the remarkably illogocal way of month/day/year. This is the day  when Pi is celebrated, usually in high schools, with all kinds of pies and various feats of memory such as those demonstrated by young  Pi, the hero in Life of Pi.

There's even Pi.org, a whole website devoted to all kinds of things round, ratio, and pi. The Exploratorium in San Fransisco will be celebrating all sorts of different things on March 14, the 25th time it has celbrated PiDay. At TeachPi.org you can find a plethora of different activities you can do with your students to celebrate Pi Day. You can have memorizing competitions to see who can memorize the most digits in the never ending Pi sequence of numbers; you can bake pies, or have students form a Pi chain of the digits in Pi. Sadly, there are no activities designed to help students learn that Pi is a ratio between the diameter and circumference of a circle. In other words, in every circle the circumference is just over 3 times (3.14 etc to be a little more precise) times longer than the diameter. (or 3.4159265358979323846264338327 950288419716939 937510 to be a little more precise, but not as precise as possible).

Amazingly almost all the student I have in my classes remember that the digitis of Pi go on for ever in a non- recurring pattern yet virtually not one of them seems to remember that it is a ratio. To try to remedy this I always bring in lots of different sized plates and have my students measure the circumferences and diameters and come up with the Pi ratio themselves. The U.S. Department of Education actually has this activity on the top of their list of things to do on Pi Day ( our Government really does do some things well).

And, of course, there are Pi Day jokes, here, and here, and there are even songs here.

So spare a thought for all those unfortunate people in the UK and other parts of the world where the date is recorded in the immensely logical format of day/month/year but who are, sadly,  not able to share in the joys and wonders of Pi Day.