Discovering Pi

My math class did a fun experiment to explain the numerical value of pi.  I thought this would be a great way to have students learn about pi without having to do a boring worksheet! 

The class divided into groups and measured the circumference of different circles.  We used a piece of string to measure the diameter and circumference of each circle.  Since the circumference of a circle is the distance around a circle, we wrapped the piece of string around the outside of the circle, then laid it flat on a meter stick to get the circumference.  It's similar to the way Ashley is measuring the circumference of my bicep in this picture from class that day. 

Then we wrote the measurements in a chart to help organize the data.  This is a picture of the worksheet we used and some of the things we measured.

After measuring five different things, we were required to divide the circumference by the diameter.  For instance, the circumference of the orange pumpkin lid was 47 cm and the diameter of the same lid was 15 cm.  Dividing 47 cm by 15 cm gave a quotient of 3.1.  The relationship discovered by this problem was circumference = diameter times 3.1 (C=3.1d).  The circumference formula I learned in school was circumference = diameter times pi.  Through this experiment I was able to figure out what pi was for myself.  This would be a great way to have students learn about pi without telling them what it equals!

I also found this video a great refresher of the information we learned about circumference in class. 

I also found this video a great refresher of the information we learned about circumference in class.