Throughout history, the humble circle has ignited debate, inflamed passions and intrigued many brilliant minds. How, you may ask? Just take a closer look at a circle near you, like the lid of your coffee cup or water bottle. Now, split that circle into two even halves by running a line through its center, and compare that length to how far your finger travels when its traces the perimeter of the lid once.
Wherever you buy your brew or your water, the distance around the circular lid will be a little over three times the distance across it! Try it again, with any circle—the wheel of a car, a ring or a clock on the wall—and the answer ALWAYS will be the same. The distance around is always a bit more than three times the distance across the middle—in fact, about 3.14 times!
This is one of the mysteries of circles that you can help your students discover next week on Pi Day, an entire day celebrating the number 3.14, which takes place on March 14. You and your students will be in good company as you puzzle over this number known as pi, or py, represented by the Greek letter π.
From the ancient Chinese to engineers at NASA, who used pi to figure out how to parachute onto the planet Mars, many people have learned that pi comes in handy. In fact, pi is about as useful as it is long—that’s infinitely long. Technically, pi can’t be written as a decimal with a limited number of decimal places, even though we typically refer to it as 3.14. Want to test this out? You can see for yourself by exactly measuring the distance around the edge of a circle, or its circumference, and dividing by that distance across the middle, or diameter.
City Year AmeriCorps members and the students they tutor and support every day in classrooms across the country will play games, work with arts and crafts and come up with other creative ways to celebrate Pi Day.
To help you talk to students next week about pi and do some fun activities too, check out the resources below. Whether or not your students end up pursuing a field like science, technology, engineering or math, they’ll find it a very useful number to know—and it’s as easy as pi!
- See how NASA Uses Pi in Space and to Visit Planets Far, Far Away
- Use Code to Bake a Perfect Pi(e)
- Many Ways to Celebrate Pi Day
- Pi Poetry! Skip the Haiku, try a Pi-ku and These Other Ways to Write and Rhyme About Pi
- All You Ever Wanted to Know About the Beginnings of Pi Day
P.S. In Greek, the word for circumference is perimetro (just like in Spanish!) The first letter in perimetro is P, which in the Greek alphabet is the symbol π!
Have other plans for celebrating Pi Day with your students and communities? Share your Pi Day events on social media with #piday and #cypiday.