Many teachers have been sharing resources for ways to celebrate "Pi Day" on March 14 (3.14- get it?) I have collected them on this page, and hope that they will be useful. All credit should go to the fabulous teachers who have contributed them to various listservs; I did not record all of the names.
Some of these ideas may also be included in the webpages below, and I'm sure many of the pages link to each other and include several of the same sites.
Pi Day memorization. Qualifying rounds on paper. Only those students who could memorize 50 digits were in the finals. They use the Pi Trainer (see website listed below). It's a web site that you simply type in the digits and it tells you how many digits you have correctly memorized and gives you the next 5 digits to study.
Pi Chain. Assign each digit a different color and using paper strips students create a pi chain. One teacher in NJ had her classes do this and when completed after 2 days was over 2000 digits long wrapping through the hallways. (They attached it to the wall near the ceiling.)
Pi Beads. One of the activities is to string pi beads. We start with a bead that is triangular in shape (to represent the 3)and then, using a different color for each digit, we string the first 20, 30 or 50 beads. The purpose is not to have the students memorize them (although many do), but to show them in a visual way that there is no pattern in the digits. We string 10 first, look for any patterns, string 10 more and see if our predictions hold, etc. We round out the unit with pi songs and other celebrations (like giving each other "high pi" in the hallway (instead of slapping high fives, they only use 3 fingers.)
Pi Quilt. Very similar except students are given 100 digits of pi (at different starting points and they color in a spiral fashion the digits from center to the outside.)
Buffont's Needle - using a toothpick and having parallel lines drawn that are the length of the toothpick apart, students drop the toothpick from about a foot above the paper record whether it lands touches a line or not.
The ratio of hits to total is 2/pi if you drop the toothpick enough.
Histogram of digits. Students compare using a histogram or circle graph the frequency of digits in the first 100 digits of pi.
Pi Approximation using spreadsheets. Using the triangle method of estimating pi, students create or use a spreadsheet to section a circle into triangles. (for pi to be correct to about 10 digits I believe you need to section the circle into about 3-6 million pieces. Great for older students!)
Pi Pictures. Give students sheet with a large pi symbol and have them create a picture around it.
Pi Songs -Several sites include these. Or, why not let the students, or even students work with their parents to create new songs? The more the merrier!
Pi Graph. Using large graph paper (like the poster board size) label the x or horizontal axis as "Diameter" and the Y-axis or vertical axis as "Circumference" . This is super for all ages and adults are always impressed by this! Take several size cylindrical objects (soda cans, quarters etc.) mark the diameter of the object on the x axis. (you don't even need to measure you simply place the left edge at the origin and the right edge you mark.) You then roll the object up carefully and mark its location after it has completed one revolution. Each object will create one point and if you connect the points the slope of the line will be Pi!
Pi Day Estimation. Using a LARGE piece of cardboard, cut out a circle and paint it colorfully (maybe even put a pi symbol in its center) Have the students estimate (guess) the number of centimeters its circumference is. Winner gets a dozen donuts (only round ones if you please)
Outdoor or indoor constructions. Using a safety compass have students draw a circle and then create a rossette by using its radius by swinging arcs about the circle. Locate the center of the compass at the intersection of the arc and the edge of the circle. This forms a 6 pointed flower. Color in if you wish. You may also do this outside with sidewalk chalk, a nail (to locate the center) and a large string.
Birthdays: Einstein and Waclaw Sierpinski. Sierpinski is great for students since they can create a Sierpinksi's triangle. Students as young as 2nd grade can color the even numbers in from PASCALS Triangle -this will create a usable version of Sierpinski's triangle. You could also create a Sierpinksi's pyramid but since these are based on triangles they may cloud the issue for Pi Day.
There's also a site for you to look up your birthday in Pi. (see links below)
Circle Art: Have students at the younger grades create pictures using only colored circles. (Teacher precuts the circles in various colors) Badge-a-minute has a circle cutter for their buttons that you can buy but it's great for cutting out circles quicly without any measuring.
Pi Day Posters: One school used as a theme "Circles are all around us" -give a prize as needed
Pi Day Poems: Why should math teachers have all the fun? Have students create free verse, haiku, acrostic, whatever.
Pi contest: One school asked students to divide out (long division) a fractional form of Pi as far as they could. One winner on was a girl who connected one hundred pages of typing paper to make a 20 foot long space for her calculations. Most kids started the problem, but gave up after a page or two.
School-wide pi: One school is circling the school with Pi. Each teacher is going to be responsible for a certain section of Pi. Construction paper colors are assigned to a particular digit and we'll make rings that are attached correspond to the part of Pi we are responsible for. As each teacher's section is completed, we'll attach it to the walls (near the ceiling) in the hallways. Each team (6 in all) is coming up with their particular Pi activity. The students will have a pie eating contest during their lunch period, the choir will sing Pi day songs...they've all ordered the SirCumference books also. It should be a fun day for the students.
And, to really catch students' interest-food!
Fun stuff - have parents donate REAL pies - have do you divide them between the students you have equitably? This is really great if all the pies are not the same circumference. COVID update-you can use pre-wrapped Little Debbie Oatmeal pies
Compare pizza prices - based on area - Do you have a Little Caesar's with square pizza? Which is the better deal - square round, Pizza Hut, Little C. or whatever the local favorite is?
Since I started collecting Pi Day ideas, they have increased exponentially! (I have tried to include only free activities that do not require you to create an account at a TpT store etc)