Pi Day

Today is Pi Day!  Yes, it doesn't quite work for us Brits, but since there aren't 14 months in the year, we just have to celebrate with the Americans on 14th March (or 3.14).

I'm giving 3 tutorials today, for a variety of abilities, and will be celebrating Pi Day in each of them.
In my first, and longest, tutorial his morning, I started by labelling the parts of a circle (Circumference, Diameter, Radius and Tangent) and got the students to measure the diameter and circumference of a variety of cylinders in order to calculate Pi. 

Then we looked at the real digits of Pi (rather than our calculated attempts) and used a rhyme found in The Joy of Pi by David Blatner:

Sir, I bear a rhyme excelling
In mystic force and magic spelling
Celestial sprites elucidate
All my own striving can't relate.
Or locate they who can cogitate
And so finally terminate. Finis.

This gives the first 32 digits of Pi, where the 33rd digit is zero.

Personally, I can only remember 3.14159265, and in fact for almost all engineering applications, 3.14159 is all the number of digits you need to remember, if you don't have a Pi Button on your calculator.  22/7 is a good approximation for when you do calculations by hand, but these days there's always a calculator/computer/phone nearby to help.

Then we used loom bands to make a Pi Bracelet: Start with 3 bands of the same colour, then use a bead on a different colour band.  Change colours again, and add 1 band.  Change colours again, and use 4 bands.  Change colours again, add 1 band.  Change colours again, use 5 bands, etc...

After this we talked about ways that Pi is used in physics: angular velocity, radians, cosmology, trigonometry, radio waves, electricity, simple harmonic motion, to name a few.  Obviously, within a 1.5hour tutorial, there was not the time to go into each topic in depth, but just enough to illustrate that Pi is actually a really useful number.

Finally, we played a card game: Deal out 5 cards to each player (removing picture cards), leaving the rest in a pile on the table.  Decide who goes first.  The first player has to put down a 3.  (Ignore the decimal point).  If they can't go, they need to pick up one card from the pile and play passes to the next person.  After the 3, a 1 needs to be placed next.  After the 1, a 4, etc. The winner is the first player to have no cards left!


With my own girls, they made Pi Bracelets from loom bands, played cards, and also made pizzas for lunch and we're having pies for dinner tonight. Most maths can be taught using food. Yum!