If you were a good student in elementary school, then you memorized pi as 3.14 and calculated all the necessary circle calculations, namely circumference and area. If you were a better student, maybe you memorized the definition of pi as the ratio of the circumference to the diameter of a circle. Better yet, maybe you had a layman’s understanding of pi which is the number of times a circle’s diameter can fit around the circle. But none of the above is fascinating. Explore a little deeper, and it’s the strange appearance of pi in the world that makes pi such a fascinating number.
History of pi: The earliest known appearance of pi was found in an Egyptian papyrus scroll, which is said to actually be a copy of an even earlier scroll, in which Ahmesis referenced pi as 256/81. The next significant appearance of pi is found in the Bible. In Kings, Solomon’s Temple is detailed in dimensions of 30 cubits and 10 cubits, hence 3, and is therefore considered to be the Hebrew’s estimation of pi. (Some scholars claim this is close enough, others squabble this point). Advance to 250 B.C. and Archimedes describes the first repetetive mathematical algorithm for the calculation of pi. Four hundred years later, Ptolemy found pi to be 377/120, which is accurate to 3 decimal places. And, around 500 A.D. in China, Tsu Ch’ung-Chih described pi as 355/113, which is accurate for six decimal places. As of August 2010, we now know pi to the 5 trillionth decimal place. It’s difficult to grasp the enormity of a trillion, much less five trillion. To give you an idea, if you typed all five trillion digits in a typical sized font, you would need a sheet of paper that goes to the moon and back five times.
Pi in Nature: Given that the value of pi was discovered in the study of circles, it’s no wonder that pi is found in so many aspects of nature. From the dilating pupils of the eye to the blood cells coursing your veins, from the ripples created by a tear drop in a coffe cup to the ripples of vibration in the air created by a single tone. Bubbles, the arc of time, the loopy paths of rivers, the orbit of planets, the waves on the beach, the helix shaped strands of DNA that form a human body or all biological life – all relate to pi.
Pi in Chaos: Chaos is another word for randomness, or chance, or better known in the math world as probability. And one of the most famous probability experiments is Buffon’s Needle. This experiment basically states that if you drop a bunch of needles onto a lined sheet of paper, the chances that a needle will cross a line is directly proportional to, you guessed it, pi. There’s a lot more details to this experiment, such as equidistant lines and the like, but you’re looking for statistical tables and equations, you’d be looking somewhere other than a general article about pi.
Pi in Everything: It’s amazing that the very same pi used by students to calculate the area of a circle on a sixth grade exam is the same number used by Einstein in his field equation of general relativity. It is also found in Heisenberg’s uncertainty principle and String Theory. This String Theory is no small thing. Also known as the Theory of Everything, it basically states that everything can be broken down (even further than atoms) into strings, and what differentiates one thing from another is the rate of each string’s vibration (very liberal paraphrasing). So now we have linked pi to, well, everything.
Pi for Fun: If you happen to be at a hat store, and can’t remember your hat size, just measure your head, divide by pi, and round to the nearest eighth of an inch. Or, if you happen to need to know the height of an elephant, and you’re brave enough to grab that elephant’s foot, you can measure the diameter of its foot, and multiply that by 2 pi for a pretty close estimate. I’ve never actually had to know an elephant’s height, so I’ve never tested the elephant formula, but the hat trick works fairly well.
Piece of Pi: An excerpt of a poem called “Pi” by Wislawa Szymborksa (Nobel prize winning poet)
…The caravan of digits that is pi
does not stop at the edge of the page,
but runs off the table and into the air,
over the wall, a leaf, a bird’s nest, the clouds, straight into the sky,
through all the bloatedness and bottomlessness.
Oh how short, all but mouse-like is the comet’s tail!…
The Life of Pi, March 13, 2006, The Independent, Retrieved 2010-12-6
Buffon’s needle, Wikipedia, Retrieved 2010-12-6
Ouellette, Jennifer,Quest to Find a Menagerie of Exotic Particles, Discovery News, 2010-12-6
Szymborska, Wislawa, pi, Famous Poets and Poems, Retrieved 12/6/2010
