…and, thanks to the magic of post scheduling, this post is going up at exactly 9:26AM on 3/14/15.

To be honest, I initially wasn’t sure what my Pi Day post should be about. I’ve already written about pie and circumference; what aspect should I cover now? The answer struck me as I recalled a question on a job application I filled out recently. I was asked what my educational philosophy was and how I had demonstrated this in previous positions. After years of studying and working in education, my response felt hackneyed, but it really is my philosophy: people learn better when they see and experience concepts rather than just memorizing facts and formulas. This requires hands-on activities and real world demonstrations. So how can we apply this to pi?

The essence of pi is that it’s the ratio between the circumference of a circle and its diameter. We don’t have to put blind faith in this formula, because we can test it for ourselves.

You will need:

a variety of round objects

a flexible tape measure (think sewing box, not tool box) OR ribbon, a marker, and a ruler

1. Take a round object. Use the tape measure or ribbon to measure across the diameter of the object; if using the ribbon, mark the length of the diameter with a marker and use the ruler to measure this length.

2. Wrap the tape measure or ribbon around the outside of the object and note its circumference; again, if using the ribbon, mark the length with a marker and measure with a ruler.

3. Repeat steps 1 and 2 with the other objects.

4. Organize your measurements into a data table like the one below. To fill in the fourth column, divide each object’s circumference by its diameter.

5. Notice how all the numbers in the fourth column are about the same? Congratulations, you’ve found pi! (To the best accuracy possible given your tools, naturally.)