March 14 is Pi Day and a classic day for celebrating math, with great pi day activities available even for elementary school. The first Pi Day was celebrated in 1988 in San Francisco, California in order to draw attention to STEM. In addition, Pi Day is Albert Einstein’s birthday! Here from Exploratorium is a great brief history of pi for your own knowledge or to share with your students.

(All links checked 2/20/23)

## Introducing and Discovering Pi

*Sir Cumference and the Dragon of Pi *is a great book for introducing the idea of pi to elementary students of any age. It is also available as a read aloud on YouTube.

If you teach older children (4th grade and up), or can work closely with a small group of younger children, I also love doing an activity where children measure circular objects using yarn or twine, then make discoveries about the relationship between the circumference and diameter.

While the National Council of Teachers of Mathematics has this as a lesson for 7th grade (when the formula will be taught) and Teacher Vision has a similar lesson for 6th-8th grade called “Discovering the Magical Pi,” I have personally done the activity in a small group setting with children as young as 2nd grade (and one very highly gifted kindergartener), who with a little guidance (as they still needed assistance with measuring and charting their data) were able to discover that the circumference is always a little more than 3 times the diameter (and were very excited!) *The Scientific American* has instructions for this lesson in their article Cir*cular Reasoning: Finding Pi.*

A simplified version for class demonstration would be to use string and a can. Wrap the string around the circumference of the can. Cut the string where it meets the beginning end. Then stretch the string across the diameter of the can, and cut this measure. Repeat twice and you should always end up with three equal lengths of string with a little left over. (idea from Global Educator Institute.)

## Math Art With Circles

Fraction Circle Art for grades 3-5. Great way to reinforce fraction skills while making circle art!

Give each student a paper circle and have them use a ruler to draw as many diameters into the circle that they can fit. They will discover that a circle has an infinite number of diameters.

Have students trace circular objects on colored paper and cut out the different sized circles, measure the diameters, and then glue in different arrangements to create circle art.

Make a poster with the theme “Circles are all around us” and real world examples of circles.

Geometric Math Art using circles to create four petaled flowers (note: this activity suggests students use compasses to draw congruent circles, but you could have them trace a circle instead)

Making Mandalas– Practice vocabulary of circumference, radius, and diameter, learn to use a compass and introduce radial symmetry with this art activity from We Are Teachers.

## Math Art Using Digits of Pi

Pi Day Skyline. Graph the digits of pi to create a city scape. (You could also represent this with Cuisenaire Rods if you want a simpler version.)

Pi Day String Art. My students LOVE paper plate yarn weaving, and here’s a fun variation from Pink Stripey Socks that uses the digits of pi.

Pi Day bracelets. Use a different color bead to represent each digit (or black beads for odd numbers and white beads for even numbers), and string them on pipe cleaners to make pi day bracelets.

Alternatively, work as a class to create a paper chain from the digits of pi, with a different color to represent each digit.

Pi Day Grid Art In this activity from Tinker Lab, students choose 3 colors and get 14 minutes to design 15 boxes however they like.

## Other Math Art

Give students a copy of a large pi symbol and have them incorporate it into a picture. Here’s one option for a free printable.

## For Very Young Students

Here is a cute preschool/kindergarten lesson for pi day. Children are introduced to pi as “math code” for measuring circles, count that today is the 3rd month and 14th day, and measure the diameters of mini pies with measuring tapes before eating them.

If you are a homeschooler or have another setting where you can drive nails into the ground here’s a lesson on How to Explain Pi to a 5 Year Old

## Pi Day Videos

The Pi Song My students LOVE this song for whatever reason! Several of them have memorized digits of pi using it.

100 Digits of Pi. Another option for a pi digits song

Math Antics Video *Circles: What Is Pi?*

## Songs to Sing

From the School District of Philadelphia Office of Curriculum and Instruction:

**Oh Number Pi (tune of O Christmas Tree)**

Oh, number Pi Oh, number Pi

Your digits are unending,

Oh, number Pi Oh, number Pi

No pattern are you sending.

You’re three point one four one five nine, And even more if we had time,

Oh, number Pi Oh, number Pi

For circle lengths unbending.

**Diameter Cheer**

Circle, Circle

Draw the Line Right through the Middle Every time, Diameter!

## Need Even More Ideas?

TeachPi.org is a whole website devoted to pi activities and resources!