Getting Around To Pi Day (Again) (H. Michael Mogil, CCM, CBM, NWA-DS*)
Note that the symbol for Pi is π, an “option p” computer keyboard command (Fig. 1). However, I will spell out Pi throughout this article.
Those of you who follow my math, meteorology and other exploits know that I like to play with numbers. Numbers are a powerful tool that helps us describe and explain our world. Numbers, like Pi, also showcase the incredible array of mathematical patterns and applications (more on this later) that we experience daily.
So, as we do each year, we celebrate Pi Day (3/14) – which accounts for the first three digits of the never-ending number, 3.1415…. (http://www.piday.org/million/). A second level Pi Day occurs on the date 3/14/15 (a once a century – i.e., once in a lifetime event).
However, if one moves further down into the number known as Pi, one can break out specific times during the day as part of the decoding process. Hence, the first ten digits of the number (3.141592653) translate into 3/14/15 and 9:26 and 53 seconds. This date-time combination also yields a twice in a single day event every century (i.e., “A twice in a lifetime celebration within a celebration”).
According to the mathforum.com web site, “Historians estimate that by 2000 B.C. humans had noticed that the ratio of circumference (C) to diameter (D) was the same for all circles.” The ratio (C/D = circumference/diameter) was 3.1415…, the value we associate with Pi, today.
However, it wasn’t until 1706, that William Jones, a mathematics teacher from England, started using the symbol “Pi.” Some 30 years later, Leonhard Euler, a well-renowned Swiss mathematician, brought the symbol into more widespread use.
The Dr. Math library at mathforum.com noted that the book, “A History of Pi” by Petr Beckmann, a 20th-century Czech researcher, provides much of the background on Pi’s evolution into mathematical circles (pun intended).
The significance of the C/D relationship borders on astonishing, because circles (and their 3-dimensional counterparts – spheres) exist everywhere. Consider tires, pie plates, pies (bake and eat one every Pi Day?), pots, turntables (old records, microwave oven plates), cross sections of some rooted vegetables (depending upon how they grew), cross sections of other fruits and vegetables (tomatoes, cantaloupes), cross sections of pipes and hoses, storms (hurricanes, tornadoes, and everyday low-pressure systems), rainbow arcs, baseballs, the pupils of our eyes, latitude and longitude, Great Circle airplane routes and Ferris Wheels. Even the new compact fluorescent light bulbs (CFLs) spiral, displaying circular patterning.
When it comes to storms, we meteorologists are using circular measurements (even if we don’t specifically use Pi) to describe the width (or diameter) of a tornado track, the sector radii or a hurricane (the hurricane is often not completely circular), and the infamous “Cone of Uncertainty,” which involves the path description of a series of circles that codify forecast error information. Fig. 2 shows a polar composite of Northern Hemisphere storms (can you find the circular pattern that describes these storms?).
Pi, certainly has led helped us understand and advance science and technology.
In closing, I am reminded of an episode of “Person of Interest,” in which Harold Finch played a substitute teacher. As he teaches his class, he remarks that any number (e.g., our birth date, our Social Security number, our address) is contained in Pi, somewhere.
You can also visit this web site – http://www.piday.org/million/ to see the first million digits of Pi. Then search for your birthday (e.g., my birthday is July 9, 1945, so I searched for 7945). That’s in Pi, twice. My wife’s birthday, however, is noticeably absent (too bad Mr. Finch). Yet, Pi itself (314, not including the decimal 3.14 at the onset of the number), appears 6 times.
And speaking of birthdays, Albert Einstein was born on this date in 1879 (he would have celebrated his 139th birthday this Pi Day); and, as if part of a master plan, noted theoretical physicist Steven Hawking died on Pi Day in 2018.
Yes, Pi is a pretty important number (with many more uses and applications than noted here). However, it may not be the most important number in math. But, that’s the subject of another article.
© 2015, 2018 H. Michael Mogil
Originally posted 3/8/15; updated 3/15/18
* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.