How to find Archimedes’ constant

Pi is the ratio of a circle’s circumference to it’s diameter.

Think of the circumference as the distance around a circle, and the diameter as the distance across it.

Pi is a mathematical constant. That means all circles, no matter their size, have this in common: the circumference is a little more than 3 times more than the diameter — about 3.14159265359 times more, to be precise.

Celebrate Pi Day — March 14, or 3-14 — by conducting your own search for pi.

To do your own test to see if the circumference of an object divided by its diameter really does always equal about 3.14, try this activity adapted from Layers of Learning.

What you need:

1. Gather cylinders from around your home. Measure the widest part of the top or bottom to find its diameter. Record the result.

2. Wrap the string around the object. Mark how much string you need to wrap all the way around. This is the circumference.

3. Measure the length of string need to wrap around the object and record it. Divide this number by the first number you recorded — how close to pi is your result? How could you make your measurements more accurate?