Pi Day is March 14

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Pi Day! Not pie. Pi!

Pi Day is observed on March 14 (3/14) in honor of the mathematical constant pi, frequently represented as 3.14. While most people learn about pi in school, some especially enthusiastic fans celebrate the constant with Pi Day festivities.

Pi Day coincides with the birthdate of Albert Einstein, which provides additional reason to celebrate.

Read on to learn more about pi and what kind of Pi Day activities it inspires.

image from PiDay.org

Countdown to Pi Day

Pi Day: March 14, 2015

What is Pi Day About?

Here’s a very helpful video from Discovery News. It explains what Pi is, why it’s important, and why people celebrate Pi Day.

Helpful introduction to Pi Day!

Top Ten Ways to Celebrate Pi Day

I've done quite a bit of research and reading about how people celebrate Pi Day. Here are my ten favorite Pi Day observances and activities. If you have suggestions, please leave a comment below! I'm always looking for more great ideas!
  • 1
    Eat some Pie. If you're having a party, serve 3.14 pies.
  • 2
    Take a pi photo. Find 2 friends and lie down in the shape of pi. Take a photo and post it!
  • 3
    Walk or run pi. It can be 3.14 miles, kilometers, blocks or laps.
  • 4
    Make pi-shaped food. Use a cookie cutter or food mold for cookies or Jell-o.
  • 5
    Wear pi. Buy or make your own pi-emblazoned shirt.
  • 6
    Memorize some pi. Start with 3.14 and go as far as you want!
  • 7
    Tell some pi jokes. Here's one to get you started.
    Q: What do you get if you divide the circumference of a bowl of ice cream by its diameter?
    A: Pi a la mode.
  • 8
    Convert numbers into units of pi. For example, if you're 31 years old, say you're 10pi.
  • 9
    Wish people "Happy Pi Day!" Especially people who don't know what you're talking about. Help get the word out.
  • 10
    Countdown to pi minute at 1:59 on March 14. It's 3/14 1:59. (3.14159) This is the quickest, easiest and least time-consuming observation of Pi Day.

How long is Pi?

hint: you'll never guess correctly

Pi has been calculated to over one trillion digits beyond its decimal point, although only 39 digits past the decimal are necessary to calculate the spherical volume of the universe. As an irrational and transcendental number, pi will continue infinitely without repetition or pattern. Pi‘s infinite nature makes it a super challenge to memorize, if you don’t mind knowing you’ll never be able to learn all of the digits.

Want to get started? I don’t have room to list an inifinite number of digits. So, here are 50 digits of pi. Enjoy!
3.14159265358979323846264338327950288419716939937510

source: Digits of pi

Why is pi so lonely?

Did you know...


3.14% of sailors are pirates.

Pi Day Pics

memes, photos, and other fun visuals

Pumpkin is my favorite kind of pi pie!

from http://cheezburger.com/6816079616

from http://brillantezzapuro.tumblr.com/post/25001660011

from http://rrothberg.tumblr.com/post/24109406470/pi-day-i-never-post-my-holiday-postings-on-the

from http://www.sosmath.com/CBB/viewtopic.php?f=8&t=58888

Pi Day Activities and Events

Believe it or not, Pi Day events are becoming more and more popular. Check this growing list to see if there's one near you, or get some ideas for starting your own Pi Day party! Have one to add to the list? Leave me a comment below!
Pi Day
The objective of this web site is to convince the world that mathematics is fun, and capitalize on the attention mathematicians' favorite number, Pi, gets on Pi Day. By promoting cool Pi-related things from around the web, we are able to demonstrate how important math is to our society today, both culturally and technically.
Pi Day Princeton
Einstein lived in Princeton, New Jersey for over 20 years, so on Pi Day the heart of Princeton celebrates his birthday and all the genius residents of our famous Ivy League town with a ton of events!
Happy Pi Day! March 14, 2014
Celebrating Pi Day with fun facts, activities & party ideas.
How to Celebrate Pi Day: 8 Steps (with Pictures) - wikiHow
How to Celebrate Pi Day. Pi is a mathematical constant that is the ratio of a circle's circumference to its diameter, and it is also one of the most revered mathematical constants in the known world.http://www.piday.org/learn-about-pi/ Pi...
Pi Day Pinata!
How to make a Pi Pinata!
Pi Day Cards, Free Pi Day eCards, Greeting Cards | 123 Greetings
Pi day is the perfect time to celebrate something that's as infinite as the value of pi, namely, your love for all those you care about. Reach out to them with our ecards and let the words speak out your feelings.
Pi-Dye T-Shirts - The Place for Pi and Math T-shirts and Other Gifts
Pi and math t-shirts, gifts, clocks, and mugs for Pi Day Assemblies, Math Clubs, Math Awards, Gifts for Math Teachers, or individual purchase.
Pi Day: pi transformed into incredible art %u2013 in pictures | Science | theguardian.com
The number 3.14159 ... as you have never seen it before. Striking computer-generated images of the most famous number in maths

Pi Day Songs

These songs are full of pi puns, which will make you giggle and/or groan. Enjoy!

Did you know...


In Alaska, where it gets very cold, pi is only 3.00. As you know, everything shrinks in the cold. They call it Eskimo pi.

Pi or Cake?

Pi Day Teacher Resources

Looking for printables and activities to incorporate into your Pi Day lesson plan? Try some of these sites for teacher resources.
Pi Day Theme Unit - Printables and Worksheets
Pi DayTheme
March 14 - History of Pi (Grades 5-8)
March 14 - Celebrating Pi Day (Grades 5-8)
What Is Pi? (Grades 5-8)Spanish
Pi - EnchantedLearning.com
Pi, 3.1416..., an explanation and printable worksheets.
Pi Day Worksheets
Use these worksheets and activities to teach your students all about the number pi.
Math Forum: T2T FAQ: Pi Day
Do you know of activities to use for a Pi Day, March 14 (3.14) celebration?
Pi Day
Pi Day is March 14. Celebrate Pi Day at Math Goodies by exploring the history and meaning of this mathematical constant.
Pi Day: Pi Activities & Links | Exploratorium
A Brief History of Pi
Pi in Second Life
Cutting %u03C0 : Carefully wrap string around the circumference of your circular object. Cut the string when it is exactly the same...
Exploring Pi | Scholastic.com
Celebrate the most useful irrational number with these fun math and geometry activities.
12 Best Pi Day Ideas for March 14th {3.14} - Tip Junkie
Pi Day is also a fun excuse for a new activity and tradition with your kids! Here are 12 Pi Day ideas which include free printables, recipes, and fun activities for kids to help celebrate Pi Day on 3.14, March 14th!
Great Pi Day Activities for Teachers - Pi Day
Here are some Pi Day Activity suggestions from 2008 submitted by teachers, students & every day people.
TeachPi.org - Lessons
A one-stop Pi Day shop for teachers and number lovers.

Are you a Pi Day fan? How do you celebrate?

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  • Arachnea Mar 15, 2014 @ 12:23 pm
    I came across you lens for Pi day on Pi day. So, I thought it apt to take a look. Fun lens. I also made sure to wish all of my colleagues a happy Pi day.
  • CarolHoule Mar 14, 2014 @ 11:34 pm
    10 trillion? I had no idea. It opened my mind. You made my day. Thank you!
  • LynnKK Mar 14, 2014 @ 8:31 pm
    I had a lot of fun telling students it was pi day Congratulations on lens of the day.
  • hmsweaver Mar 14, 2014 @ 11:29 pm
    Thank you! Glad you could share it with the students!
  • rauspitz Mar 14, 2014 @ 8:05 pm
    I barely passed geometry, no way I'm celebrating. Seriously, this was a fun lens. Congratulations on getting LotD!
  • hmsweaver Mar 14, 2014 @ 11:29 pm
    LOL! Thank you!
  • philipcaddick Mar 14, 2014 @ 6:07 pm
    sounds like such a lot of fun
  • vegival Mar 14, 2014 @ 5:24 pm
    My co-workers were surprised and a little confused but very happy when I brought coconut cream pie (decorated with a chocolate chip pi) to work to celebrate!
  • hmsweaver Mar 14, 2014 @ 11:30 pm
    Excellent way to share the holiday with them! Great job!
  • boneworld Mar 14, 2014 @ 2:52 pm
    We celebrate this every year where I work. It's a great day for trying all kinds of strange kinds of pie.
  • hmsweaver Mar 14, 2014 @ 11:31 pm
    Any excuse for more pie is good!
  • ChocolateLily Mar 14, 2014 @ 1:14 pm
    I totally forgot it was Pi Day! Duh! Thanks for reminding me!
  • hmsweaver Mar 14, 2014 @ 11:32 pm
    You're welcome!
  • Spirality Mar 14, 2014 @ 11:32 am
    I never knew there was a Pi Day.
  • hmsweaver Mar 14, 2014 @ 11:32 pm
    Glad to introduce you to the holiday!
  • mountainmist Mar 14, 2014 @ 11:19 am
    Great lens! Wasn't aware of Pi Day but am a fan now!
  • hmsweaver Mar 14, 2014 @ 11:35 pm
    Hooray for a new Pi Day fan!
  • Heather426 Mar 14, 2014 @ 10:33 am
    Well I'm a fan of pie, does that count? LOL Now that I know about it , I'm a fan of Pi Day. I find mathematics fascinating especially how it underpins the structure of the Universe.
  • hmsweaver Mar 14, 2014 @ 11:36 pm
    Yes! I love pie and pi!
  • Steve_Kaye Mar 14, 2014 @ 10:33 am
    I'm going to find a way to include pi in every sentence today.
  • hmsweaver Mar 14, 2014 @ 11:36 pm
    Excellent goal! :-)
  • StephenJParkin Mar 14, 2014 @ 10:23 am
    Not really but it is a fascinating number. Did you know that you can prove a straight line is a circle? This is done by mapping all the tangents to a circle and differentiating to the nth degree where n tends to infinity. The resulting graph can be shown to be continuous and hence +infinity is equal to -infinity at which point the straight line meets itself and it is therefore an infinite circle. The Universe can be plotted in the same way and is therefore an infinite globe.

    This weird mathematical fact is not explainable in our 4d world and could not be done had we not discovered Pi. No wonder it is called an irrational number! Well done on the LOTD!
  • hmsweaver Mar 14, 2014 @ 11:37 pm
    Wow! I didn't remember learning all of those fascinating things. Thanks for the info!
  • partybuzz Mar 14, 2014 @ 10:21 am
    Happy Pi Day! Congratulations on LotD!
  • hmsweaver Mar 14, 2014 @ 11:38 pm
    Thank you very much!
  • d-artist Mar 14, 2014 @ 10:12 am
    Congratulations on LOTD! Very interesting, really never thought about Pi being a special day...and now I have another celebrating day to honor.
  • hmsweaver Mar 14, 2014 @ 11:39 pm
    I love celebrating! Glad you have a new holiday. :-)
  • RenaissanceWoman2010 Mar 14, 2014 @ 9:58 am
    An excellent reason to celebrate. Maybe I'll bake a birthday Pi for Albert. Congrats on LotD!
  • hmsweaver Mar 14, 2014 @ 11:39 pm
    I think he would appreciate that!
  • Susan52 Mar 14, 2014 @ 9:48 am
    Fun! I love the sailors/pirates statistic. Guess I'd better celebrate, probably with a pie. Congratulations on your very entertaining and informative Lens of the Day!
  • hmsweaver Mar 14, 2014 @ 11:40 pm
    Thank you! Don't let the pirates steal your pie. :-)
  • grammieo Mar 14, 2014 @ 9:27 am
    No, but after this lens I think I'm missing out on a good celebration! congratulations on LoTD! This is a great lens!
  • hmsweaver Mar 14, 2014 @ 11:40 pm
    Thank you!
  • KathyT Mar 14, 2014 @ 9:25 am
    Congratulations on your LotD! I have never understood Pi, and even listening to the video, I'm even more confused. I cannot wrap my head around how anyone could have come up with this to begin with. :)
  • hmsweaver Mar 14, 2014 @ 11:48 pm
    Thank you for visiting!
  • Merrci Mar 14, 2014 @ 9:09 am
    Just stopped back by to congratulate you on LofT! That is wonderful, and still another reason to celebrate today. Love your lens!
  • hmsweaver Mar 14, 2014 @ 11:48 pm
    Thank you so much!
  • parkseungwoo Mar 14, 2014 @ 9:05 am
    wonder pie
  • VioletteRose Mar 14, 2014 @ 8:06 am
    This is interesting, I never knew that a day is celebrated in honor of Pi. Thanks for sharing!
  • hmsweaver Mar 14, 2014 @ 11:49 pm
    Thanks for stopping by!
  • esmonaco Mar 14, 2014 @ 4:52 am
    I had no Idea that Pi was celebrated!!! Where have I been?? Very nice, Thanks and Congratulations on LOTD!!!
  • hmsweaver Mar 14, 2014 @ 11:56 pm
    Thank you for visiting!
  • dilipyadav Mar 14, 2014 @ 2:22 am
    reall nice and fun lens!
    shared it.
  • hmsweaver Mar 14, 2014 @ 11:57 pm
    Thank you for visiting and sharing!
  • Brite-Ideas Mar 14, 2014 @ 2:19 am
    lol! funny - congratulations on LOTD - Love how Pi shrinks in Alaska lol!
  • hmsweaver Mar 15, 2014 @ 12:00 am
    Thank you!
  • Mar 14, 2014 @ 12:19 am
    It's really a fun and cute lenses, very happy to see them!
  • hmsweaver Mar 15, 2014 @ 12:01 am
    Thank you!
  • kiwinana71 Mar 03, 2014 @ 8:32 pm
    Interesting this is the first time I have heard of Pi day. Sorry I don't celebrate, but at least I learnt something new today by reading this page Thanks.
  • hmsweaver Mar 03, 2014 @ 11:06 pm
    Thanks for stopping by! And now you know! :-)
  • Merrci Mar 02, 2014 @ 7:02 pm
    Fun and cute and a big congratulations for your 100th! That's very exciting and still another cause to celebrate!
  • hmsweaver Mar 03, 2014 @ 10:26 am
    Thank you Merrci!!

Epic Pi Day in 2015

An extra-special Pi Day is coming up in 2015! On March 14, 2015 at 9:27, the date and time will look like the numerical representation of pi to seven digits past the decimal point: 3.1415927

Put it on your calendar now, so you don't miss this epic Pi Day!