Happy Pi Day!

Every year on 3.14 (get it?), number enthusiasts celebrate Pi Day (which also happens to be Albert Einstein’s birthday). Pi is “the name of a symbol (π) used in geometry for the ratio of the circumference of a circle to its diameter or 3.1415927,” first used by Swiss mathematician Leonhard Euler in 1748. According to the Online Etymology Dictionary, the word comes from the Greek letter pi (which comes from the Hebrew word for “little mouth”), as an abbreviation of the Greek periphereia, meaning “periphery,” referring to the periphery or diameter of a circle.

(Pi also means “printing-types mixed together indiscriminately; type in a confused or jumbled condition or mass,” but this is probably an alteration of pie, with the idea of a medley or magpie, a bird known for pilfering and hoarding a medley or jumble of objects.)

Piphilology “comprises the creation and use of mnemonic techniques to remember a span of digits of the mathematical constant π.” The word is a blend of pi and philology, “the study of language,” which comes from the Greek philologos, “fond of learning or of words.” A mnemonic (from the Greek mnemonikos, “of or pertaining to memory”) is “a device, such as a formula or rhyme, used as an aid in remembering.”

A piem is such a device for memorizing the digits of pi (if you’re so inclined). A portmanteau of pi and poem, piems “represent π in a way such that the length of each word (in letters) represents a digit.” A famous piem is “How I need a drink, alcoholic of course [or, in nature] after the heavy lectures involving quantum mechanics,” developed by Sir James Jeans, an English physicist, astronomer, and mathematician. For more piems, check out Pi Wordplay from Wolfram Math World.

Another type of mnemonic is a visual mnemonic, which works “by associating an image with characters or objects whose name sounds like the item that has to be memorized.” A simple visual mnemonic for identifying one’s drinking glass and bread plate while dining in a formal setting with others is to form a lower case B with one’s left hand and a lower case D with one’s right. One’s drinking glass, represented by D, is on the right, while one’s bread plate, represented by B, is on the left.

First-letter mnemonics take the first letter of each word of a list of words, and form an acronym, a phrase, or a name. HOMES is an acronym used for memorizing the Great Lakes of North America, consisting of Lakes Huron, Ontario, Michigan, Erie, and Superior. SOHCAHTOA is used for remembering the trigonometric functions “sine equals opposite over hypotenuse; cosine equals adjacent over hypotenuse; tangent equals opposite over adjacent.”

Dear King Philip Come Over For Good Spaghetti is just one of many phrase mnemonics used for memorizing taxonomy in biology (domain, kingdom, phylum, class, order, family, genus, species). A mnemonic for memorizing the planets is My Very Energetic Mother Just Served Us Nine Pizzas (Mercury, Venus, Earth, Mars, Jupiter, Uranus, Neptune, and Pluto), or My Very Educated Mother Just Served Us Nachos, for those anti-planet Pluto. Roy G. Biv is a name mnemonic used for remembering “the color sequence of the visible spectrum” (red, orange, yellow, green, blue, indigo, violet). For even more first-letter mnemonic devices, visit this list – add your own!

Whatever mnemonic device you use, have fun memorizing a million digits of pi!

[Photo via Flickr, CC BY 2.0 by medea_material]

The Three Rs: ’Rithmetic

Illustration Friday - Resolution

We’ve brought you words about reading and words about writing. Now it’s time for the last of the three Rs: arithmetic.

Arithmetic, “the theory of numbers; the study of the divisibility of whole numbers, the remainders after division, etc.,” comes from arithmos, the Greek word for “number” (arithmein means “to count”). Arithmos brings us number-related words such as arithmometer, “an instrument for performing multiplication and division”; arithmocracy, “rule or government by a majority”; arithmancy, “divination using numbers that are the equivalent of letters of a name”; and arithmomania, “a morbid impulse to work over mathematical problems, or to count objects or acts, such as buttons, steps, etc.” (which apparently afflicts vampires in particular).

Arithmos also gives us logarithm, “for a number x, the power to which a given base number must be raised in order to obtain x,” “coined by Scottish mathematician John Napier” in the 1610s, with the Greek logos meaning “proportion, ratio, word.” (John Napier was also the inventor of Napier’s bones, “a set of numbered rods used for multiplication and division.”)

A word often mistakenly attributed to arithmos is algorithm, “a precise step-by-step plan for a computational procedure that begins with an input value and yields an output value in a finite number of steps.” Algorithm is actually an alteration of algorism, “the Arabic system of notation; hence, the art of computation with the Arabic figures, now commonly called arithmetic,” which comes from the Middle Latin algorismus, “a mangled transliteration of Arabic al-Khwarizmi ‘native of Khwarazm,’ surname of the mathematician whose works introduced sophisticated mathematics to the West.”

Algebra comes from the Middle Latin algebra, which comes from the Arabic “al jebr ‘reunion of broken parts,’ as in computation,” and was used in the 9th century by Baghdad mathematician, Abu Ja’far Muhammad ibn Musa al-Khwarizmi, as the title of his famous treatise on equations (‘Kitab al-Jabr w’al-Muqabala’ ‘Rules of Reintegration and Reduction’), which also introduced Arabic numerals to the West. In 15- and 16-century English, algebra was used “to mean ‘bone-setting,’ probably from Arab medical men in Spain.”

Geometry, “that branch of mathematics which deduces the properties of figures in space from their defining conditions, by means of assumed properties of space,” comes from the Greek geōmetrein, “to measure land.” Related to geometry, aside from all those geo- words, is gematria, “a cabalistic system of Hebrew Biblical interpretation, consisting in the substitution for a word of any other the numerical values of whose letters gave the same sum.” Trigonometry, “the branch of mathematics that deals with the relationships between the sides and the angles of triangles and the calculations based on them, particularly the trigonometric functions,” contains the Greek trigōnon, “triangle.”

Calculus, “any highly systematic method of treating a large variety of problems by the use of some peculiar system of algebraic notation,” comes from the Latin calculus, “reckoning, account,” which meant originally “small stone used in reckoning,” and is diminutive of calx, “small stone for gaming” or “limestone.” In pathology, calculus refers to “inorganic concretions of various kinds formed in various parts of the body” while the root calx brings us a number of counting and stone-related words. There’s calcium, calcified, and calcific. There’s chalk and caulk. There’s calculating and calculator.

Speaking of calculators, check out these ancient calculating devices, including the quipu, “a recording device, used by the Incas, consisting of intricate knotted cords”; the abacus, which comes from the Greek abax, “counting board,” which may have come from the Hebrew ‘ābāq, “dust”; and the jetton, “a piece of metal, generally silver, copper, or brass, bearing various devices and inscriptions, formerly used as a counter in card-playing, or in casting up accounts.” Jetton comes from the French jeton, “coin-sized metal disk, slug, counter,” which may have also brought us jitney, a small bus, “perhaps because the buses’ fare was a nickel,” like a jeton.

Want more? Check out this mathematical list, these mathematical delights, and these mathaphors. Or you may like these really really large numbers, these imaginary numbers, or these different ways to say zero.

There’s a positive googolplex of words about math and numbers. These are just a few.

Helvetica, math, bloggers

A few small bits:

Helvetica: The Movie. A movie about a font — font meets girl, font loses girl, etc. Great concept, and its web site is, as one might expect from such a high-design project, quite lovely as well.

I recently came across what amounts to a math dictionary. Definitely not high-design, but the content is very well done, and it includes many citations, the best part of any dictionary.

Lastly, a few Wordie regulars have graciously agreed to contribute to this blog on an occasional, informal basis. Stay tuned 🙂