Stolen out right from Rebecca Strom in my LINCS https://community.lincs.ed.gov/ adult ed group:
“I LOVE having students discover pi!
I pass around tape measures and circular objects of varying sizes, everything from a platter to a poker chips. In groups they measure everything you can about a circle with a tape measure- around and across. We talk about the vocabulary:definition of a circle, diameter, circumference, perimeter,etc… As they measure we record their data on the board in a chart: circle number, diameter and circumference. I tell them, it doesn’t matter if they choose inches or cm, as long as their label is consistent. After we have good variety of information, we step back and look at the data, and look for a pattern. There is always someone who notices that the circumference is approximately three times as big as the diameter. We talk about that our measurements aren’t the most accurate, because of our tools, but the more accurate you get, the closer you get to pi. Not only is this a GREAT way to discover pi, it is also a great way to learn t hat formulas aren’t “invented”, but rather they are a pattern/relationship that was discovered and then recorded.
Today I want to try extending it. So after we “predict the circumference is about 3 times as big”, taking circles we haven’t measured, measure the diameter, and predict the circumference, and then again starting with the circumference and predict/estimate the diameter.
I’m so excited to do this in both of my classes today!
Hope you all have a fun pi day!!!”