Pondering π

Pi is such a lovely little thing.  It’s shape (π) could easily be mistaken for an Ikea-designed seat, structured – oh so elegantly – to support our posterior.

Isn’t it remarkable that this delightfully formed Greek letter has come to mean so much more than its place in the alphabet warrants?

The ubiquitous nature of Pi is taken for granted, even though our lifestyle is dependent on this little number.  The ratio between the circumference of a circle and its diameter is the underpinning of traditional technologies – the piston, the electric motor, the spindle, and the sewage pipe (try living without that).

I can’t claim to remember when I first encountered Pi.  It was too long ago.  However, I do remember first beginning to fret about it.  My childish mind worried that we had got it wrong.  How could we be sure the ratio was always the same!  If it wasn’t, everything would fall apart- quite literally.  Could I ever again trust the wheels on the bus to go round and round?

It was impossible to believe that an ancient Greek had determined Pi accurately.  In my youthful imagination, a tunic-clad gentleman explored this ratio by careful measurements of multiple circles.  His efforts were stymied by the technological limitations of his time, and he struggled to create a perfect circle without the relatively complex device to be found in my school satchel – the student compass.

Perhaps, I speculated, our proto-scientist had observed the centrifugal force of the potter’s wheel, and noticed the top of Greek urn was a near perfect circle.  He might have discovered this phenomenon since he was a rather bright fellow.  But such a notion was a little too poetical.

Alternatively, my mind saw this poor tool-deprived man using a branch to scribe numerous circles in the dusty earth, and spitting out dirt for his efforts.

Whatever his approach to finding circles worthy of measurement, I was quite certain our friend was subjected to the muttered comments of a passing shepherd – something about doing real work.  Or maybe, a wheelwright stopped by to admonish our intrepid mathematician, pointing out there was no need for this foolishness since the wheel was already invented.  But our Greek hero labored on – thank the gods – despite the lack of immediate application for the knowledge he sought.

And then there was the problem of how our friend measured the curved dimensions of his circles.  Did he use yarn placed around the circumference, as I had in school?  Despite my tender years, I was a knitter and, consequently, had an instinctive understanding of tension and elasticity.  Did the Greek (a mere man, unversed in the feminine arts) appreciate that his measurements were suspect regardless of which stranded material he used.

Eventually, as I matured, the prevalence of Pi taught me to trust its value, and I became convinced that the ratio was proven. Furthermore, adulthood brought with it the knowledge that the value of Pi had been mathematically determined – my own bias towards the experimental approach notwithstanding.  At last, I could board a bus with confidence.

Until the bus began to rattle. Then I had to wonder…