In order to celebrate Pi Day, we TED-Ed nerds are bringing you 3 fun facts about our favorite irrational number!
1. Pi is infinite! To write it out, you’d begin with 3.14159 and continue on….forever! That’s why, instead of trying to write out an infinite number of digits every time, we just refer to it using the Greek letter, Pi.
2. Pi is an irrational number, or a number that can never be expressed as a ratio of 2 whole numbers.
3. Scientists have used Pi to calculate the density of our entire universe, which has infinitely less stuff in it than the total number of digits in Pi.
On March 14, we will join people across the U.S. as they celebrate an icon of nerd culture: the number pi.
So well known and beloved is pi, also written π or 3.14, that it has a national holiday named in its honor. And it’s not just for mathematicians and rocket scientists. National Pi Day is widely celebrated among students, teachers and science fans, too. Read on to find out what makes pi so special, how it’s used to explore space and how you can join the celebration with resources from our collection.
1—Remind me, what is pi?
Pi, also written π, is the Swiss Army knife of numbers. No matter how big or small a circle – from the size of our universe all the way down to an atom or smaller – the ratio of a circle’s circumference (the distance around it) to its diameter (the distance across it) is always equal to pi. Most commonly, pi is used to answer questions about anything circular or spherical, so it comes in handy especially when you’re dealing with space exploration.
2—How much pi do you need?
For simplicity, pi is often rounded to 3.14, but its digits go on forever and don’t appear to have any repeating patterns. While people have made it a challenge to memorize record-breaking digits of pi or create computer programs to calculate them, you really don’t need that many digits for most calculations – even at NASA. Here’s one of our engineers on how many decimals of pi you need.
3—Officially official.
Pi pops up in everything from rocket-science-level math to the stuff you learn in elementary school, so it’s gained a sort of cult following. On March 14 (or 3/14 in U.S. date format) in 1988, a physicist at the San Francisco Exploratorium held what is thought to be the first official Pi Day celebration, which smartly included the consumption of fruit pies. Math teachers quickly realized the potential benefits of teaching students about pi while they ate pie, and it all caught on so much that in 2009, the U.S. Congress officially declared March 14 National Pi Day. Here’s how to turn your celebration into a teachable moment.
4—Pi helps us explore space!
Space is full of circular and spherical features, and to explore them, engineers at NASA build spacecraft that make elliptical orbits and guzzle fuel from cylindrical fuel tanks, and measure distances on circular wheels. Beyond measurements and space travel, pi is used to find out what planets are made of and how deep alien oceans are, and to study newly discovered worlds. In other words, pi goes a long way at NASA.
5—Not just for rocket scientists.
No Pi Day is complete without a little problem solving. Even the math-averse will find something to love about this illustrated math challenge that features real questions scientists and engineers must answer to explore and study space – like how to determine the size of a distant planet you can’t actually see. Four new problems are added to the challenge each year and answers are released the day after Pi Day.
6—Teachers rejoice.
For teachers, the question is not whether to celebrate Pi Day, but how to celebrate it. (And how much pie is too much? Answer: The limit does not exist.) Luckily, our Education Office has an online catalog for teachers with all 20 of its “Pi in the Sky” math challenge questions for grades 4-12. Each lesson includes a description of the real-world science and engineering behind the problem, an illustrated handout and answer key, and a list of applicable Common Core Math and Next Generation Science Standards.
7—How Do We celebrate?
In a way, we celebrate Pi Day every day by using pi to explore space. But in our free time, we’ve been known to make and eat space-themed pies, too! Share your own nerdy celebrations with us here.
8—A pop-culture icon.
The fascination with pi, as well its popularity and accessibility have made it a go-to math reference in books, movies and television. Ellie, the protagonist in Carl Sagan’s book “Contact,” finds a hidden message from aliens in the digits of pi. In the original “Star Trek” series, Spock commanded an alien entity that had taken over the computer to compute pi to the last digit – an impossible task given that the digits of pi are infinite. And writers of “The Simpsons,” a show known for referencing math, created an episode in which Apu claims to know pi to 40,000 digits and proves it by stating that the 40,000th digit is 1.
9—A numbers game.
Calculating record digits of pi has been a pastime of mathematicians for millennia. Until the 1900s, these calculations were done by hand and reached records in the 500s. Once computers came onto the scene, that number jumped into the thousands, millions and now trillions. Scientist and pi enthusiast Peter Trueb holds the current record – 22,459,157,718,361 digits – which took his homemade computer 105 days of around-the-clock number crunching to achieve. The record for the other favorite pastime of pi enthusiasts, memorizing digits of pi, stands at 70,030.
10—Time to throw in the tau?
As passionate as people are about pi, there are some who believe things would be a whole lot better if we replaced pi with a number called tau, which is equal to 2π or 6.28. Because many formulas call for 2π, tau-enthusiasts say tau would provide a more elegant and efficient way to express those formulas. Every year on Pi Day, a small debate ensues. While we won’t take sides, we will say that pi is more widely used at NASA because it has applications far beyond geometry, where 2π is found most often. Perhaps most important, though, for pi- and pie-lovers alike is there’s no delicious homonym for tau.
Romantic chemistry is all about warm, gooey feelings that gush from the deepest depths of the heart…right? Not quite. Actually, the real boss behind attraction is your brain, which runs through a very quick, very complex series of calculations when assessing a potential partner. Check out these 11 GIFs from Dawn Maslar’s TED-Ed Lesson ‘The science of attraction‘ to get your attractors warmed up in time for Valentine’s Day.
We know. The idea of so much of our attraction being influenced by chemicals and evolutionary biology can seem cold and scientific rather than romantic. But the next time you see someone you like, try to appreciate how your entire body is playing matchmaker to decide if that beautiful stranger is right for you.
After all, just because the calculations are happening in your brain doesn’t mean those warm, fuzzy feelings are all in your head. In fact, all five of your senses play a role, each able to vote for (or veto) a budding attraction.
1. Sight - The eyes are the first components in attraction. Many visual beauty standards vary between cultures and eras, but signs of youth, fertility and good health, such as long lustrous hair, or smooth, scar-free skin are almost always in demand because they’re associated with reproductive fitness.
2. Smell - The nose’s contribution to romance is more than noticing perfume or cologne. It’s able to pick up on natural chemical signals known as pheromones. These not only convey important physical or genetic information about their source but are able to activate a physiological or behavioral response in the recipient.
3. Hearing - Our ears also determine attraction. Studies have shown that heterosexual men prefer females with high-pitched, breathy voices and wide formant spacing, correlated with smaller body size, while heterosexual women prefer low-pitched voices with a narrow formant spacing that suggest a larger body size.
4. Touch - And not surprisingly, touch turns out to be crucial for romance. In one experiment, not realizing the study had begun, participants were asked to briefly hold a coffee, either hot or iced. Later, the participants read a story about a hypothetical person and were asked to rate their personality. Those who had held the hot cup of coffee perceived the person in the story as happier, more social, more generous, and better-natured than those who had held the cup of iced coffee, who rated the person as cold, stoic and unaffectionate.
5. Taste - If a potential mate has managed to pass all these tests, there’s still one more: the infamous first kiss, a rich and complex exchange of tactile and chemical cues, such as the smell of one’s breath and the taste of their mouth. This magic moment is so critical that a majority of men and women have reported losing their attraction to someone after a bad first kiss.
Once attraction is confirmed, your bloodstream is flooded with norepinephrine, activating your fight or flight system. Your heart beats faster, your pupils dilate, and your body releases glucose for additional energy — not because you’re in danger but because your body is telling you that something important is happening. To help you focus, norepinephrine creates a sort of tunnel vision, blocking out surrounding distractions, possibly even warping your sense of time, and enhancing your memory. This might explain why people never forget their first kiss.
Ah, romantic love; beautiful and intoxicating, heart-breaking and soul-crushing… often all at the same time! Why do we choose to put ourselves though its emotional wringer? Does love make our lives meaningful, or is it an escape from our loneliness and suffering? Is love a disguise for our sexual desire, or a trick of biology to make us procreate? Is it all we need? Do we need it at all?
If romantic love has a purpose, neither science nor psychology has discovered it yet – but over the course of history, some of our most respected philosophers have put forward some intriguing theories.
1. Love makes us whole, again / Plato (427—347 BCE)
The ancient Greek philosopher Plato explored the idea that we love in order to become complete. In his Symposium, he wrote about a dinner party at which Aristophanes, a comic playwright, regales the guests with the following story. Humans were once creatures with four arms, four legs, and two faces. One day they angered the gods, and Zeus sliced them all in two. Since then, every person has been missing half of him or herself. Love is the longing to find a soul mate who will make us feel whole again… or at least that’s what Plato believed a drunken comedian would say at a party.
2. Love tricks us into having babies / Schopenhauer (1788-1860)
Much, much later, German philosopher Arthur Schopenhauer maintained that love, based in sexual desire, was a “voluptuous illusion”. He suggested that we love because our desires lead us to believe that another person will make us happy, but we are sorely mistaken. Nature is tricking us into procreating and the loving fusion we seek is consummated in our children. When our sexual desires are satisfied, we are thrown back into our tormented existences, and we succeed only in maintaining the species and perpetuating the cycle of human drudgery. Sounds like somebody needs a hug.
3. Love is escape from our loneliness / Russell (1872-1970)
According to the Nobel Prize-winning British philosopher Bertrand Russell we love in order to quench our physical and psychological desires. Humans are designed to procreate; but, without the ecstasy of passionate love, sex is unsatisfying. Our fear of the cold, cruel world tempts us to build hard shells to protect and isolate ourselves. Love’s delight, intimacy, and warmth helps us overcome our fear of the world, escape our lonely shells, and engage more abundantly in life. Love enriches our whole being, making it the best thing in life.
4. Love is a misleading affliction / Buddha (~6th- 4thC BCE)
Siddhartha Gautama. who became known as ‘the Buddha’, or ‘the enlightened one’, probably would have had some interesting arguments with Russell. Buddha proposed that we love because we are trying to satisfy our base desires. Yet, our passionate cravings are defects, and attachments – even romantic love – are a great source of suffering. Luckily, Buddha discovered the eight-fold path, a sort of program for extinguishing the fires of desire so that we can reach ‘nirvana’ – an enlightened state of peace, clarity, wisdom, and compassion.
5. Love lets us reach beyond ourselves / Beauvoir (1908-86)
Let’s end on a slightly more positive note. The French philosopher Simone de Beauvoir proposed that love is the desire to integrate with another and that it infuses our lives with meaning. However, she was less concerned with why we love and more interested in how we can love better. She saw that the problem with traditional romantic love is it can be so captivating that we are tempted to make it our only reason for being. Yet, dependence on another to justify our existence easily leads to boredom and power games.
To avoid this trap, Beauvoir advised loving authentically, which is more like a great friendship: lovers support each other in discovering themselves, reaching beyond themselves, and enriching their lives and the world, together.
Though we might never know why we fall in love, we can be certain that it’ll be an emotional rollercoaster ride. It’s scary and exhilarating. It makes us suffer and makes us soar. Maybe we lose ourselves. Maybe we find ourselves. It might be heartbreaking or it might just be the best thing in life. Will you dare to find out?
Michael Bierut, Pentagram partner and Senior Critic at the Yale School of Art
Posters produced for the Yale School of Architecture are now archived and a “selection of the posters can be viewed in Forty Posters for the Yale School of Architecture published by Winterhouse Editions and Mohawk Fine Papers.”
