Mnemonic Devices

Mnemonic devices are tricks and techniques used as aids in memorization. This page presents a number of them, though it just barely scratches the surface.

As James Burke presented it in "The Day the Universe Changed" (1985), before Gutenberg and his printing press got us into the habit of looking everything up in a book, we used to have to memorize almost everything we knew. Long apprenticeships were needed not just to learn and practice the skills, but also to memorize all the knowledge that went with those skills. Study at the ancient academies involved the memorization of the literature, somewhat akin to our trying to memorize an entire encyclopedia (memorizing an entire book would be trivial in comparison; most of us are challenged just with a single phone number)¹. Even in the present day, some professions require the memorization of large bodies of knowledge since it would be impossible to look everything up in the middle of their work; eg, surgeons needing to memorize anatomy (eg, the cranial nerves in order) and police officers needing to memorize all the laws that they are going to need to enforce (when a police officer moves to another state, he then needs to memorize the laws of that state).

As a result, a wide variety of tricks have been devised through the ages to aid in the task of memorizing everything. Souvenirs and commemorative items (eg, coins, medallions, knives) had the very real and useful purpose of associating the event or place with the object so that viewing or handling the object would aid in recalling the associated event or place. Neophyte Masons, having to memorize secret rituals which must not written down, are trained by an experienced Mason with the aid of a crib book containing only the for first letter of each word in the ritual (BTW, I am not a Mason, but someone I knew was becoming one). Similarly, with ritual we remember complete procedures exactly and in the right sequence, ranging from full-blown ceremonies to our daily getting-up and getting-ready-to-face-the-world preparations that must not be varied lest we forget something (such as forgetting to shave or leaving our wallet at home). ².

Rhymes and songs are incredibly useful for remembering a large quantity of words in an exact order. After several years and even decades, we can still remember the words to poems and songs. According to Burke, medieval news was spread by minstrel songs which, once heard, were immediately memorized and members of the audience could then sing them to others thus spreading the news rapidly.

And Burke's assessment of the elaborate artwork in the Catholic churches was that it wasn't art, but rather it was learning! The artwork would depict the stories and lessons that the illiterate congregation had been taught, thus triggering the congregants' memories to recount those stories and lessons to themselves. In contrast, Protestantism arose and spread with the printing press -- its very origin and original spread is credited to someone having set Martin Luther's 95 Theses to type and distributing hundreds of copies to other cities thus turning a localized protest into a continent-wide revolution.

One of the first works commissioned for printing was the Bible, so Protestantism tended to base itself much more on the individual members reading Scripture themselves -- one of the primary early functions of Sunday School was to teach everybody, adults and children alike, how to read. As a result, Protestant churches tended to be much plainer and devoid of graphic art. They didn't need those mnemonic devices as much because they had the printed word to refer back to. They also started losing their prodigious ability to memorize.

The printing of Bibles also facilitated the distribution of Martin Luther's German translation of the Bible, earning him credit for the invention of the modern German language. Many terms in the Latin Bible did not exist in German, so other Bible translators would just simply use the Latin for those terms, which meant that even though a German was reading the Bible in his own language, he still had to learn some Latin to be able to read it. Those Latin words are constructed from Latin stems plus Latin prefixes and suffixes, so Martin Luther translated each part of the untranslatable Latin words into their German equivalents and constructed new German words with the same meaning as the Latin words. And since most literate Germans' homes would have a Bible which they could refer to, that new approach to German words caught on and became a salient feature of the language that modern students of German still marvel (and curse) at.

Even though we no longer need to memorize on the vast scale that we used to, there are still some things that we want and need to commit to memory. In keeping with the greatly reduced scale of our memorization needs, the variety of mnemonic devices available to us has also reduced and many have been lost, though they could be reinvented if necessary, I am sure. For the most part, we only use a few rhymes and several catch-phrases any more. It is these catch-phrases that I have decided to collect here.

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¹ In Rabbinic Literature class, we were taught that rabbinic students were required to memorize the Torah (the first five books of the Old Testatment, AKA "Pentatuch", "Books of Moses", "The Law") and other Scripture. During the Diaspora, the Talmud was compiled and the students had to memorize that as well. Since the Talmud is truly encyclopedia in size and has no indexing nor other forms of organization, memorizing it is not only a daunting task, but also a necessary one since it would be extremely difficult and time-consuming to try to look something up in it (better to have it memorized than to try to look something up).

That practice was even to be found to some extent in European gentile universities. Since books were so rare and valuable, the practice was to gather students together in a hall to listen to someone read the single copy of a book to them. These readings were called "lectures" and so those halls became "lecture halls." In addition, in order to graduate you would need to pass your oral exams which not only test what you know but perhaps more importantly what you have memorized.

An illustration of the rabbinic practice of memorization is found in a famous story in the Pirke Avoth ("Sayings of the Fathers" -- if you ever watched Barbra Streisand's 1983 movie, "Yentl", you heard her quote several of those sayings; eg, "The more learning the more life.").

The Pirke Avoth contains a semi-famous story from c. 20 BCE about a gentile who went from one Jewish academy to another challenging the head rabbi to teach him "the whole of the Law while standing on one foot." Since every rabbi was expected to have memorized the entire Torah, that part was not too much to expect even though it would still be a non-trivial task, especially if you were expected to do so within the time that the gentile could stand on one foot, which made that demand just plain ridiculous. Needless to say, the most common response to his ridiculous demand would be getting chased off the property with a stick as he so richly deserved.

Notably, the response of the head rabbi of the Pharisees, Rabbi Hillel, was quite different:

What is hateful to you, do not do to your neighbor. That is the whole Torah; the rest is the explanation of this -— go and study it!

This was the Golden Rule showing up as a Pharisee teaching a full half century before Jesus' version.

This story has been repeated a number of times in popular culture, most notably for our generation in the first season Star Trek:TOS episode, Dagger of the Mind written by S. bar David (a pseudonym of Shimon Wincelberg), but in which the rabbi became a "philosopher" being demanded to "recite all the world's wisdom while standing on one foot."

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² Two examples from the cinema and TV come immediately to mind that I feel demonstrate the role of ritual in memorization:

1. In Mad Max: Beyond Thunderdome, the children had developed an elaborate ritual retelling and re-enactment of the story of how they had arrived at that place and of their long wait to be rescued by Capt. Walker ("We ain't been slack, Captain Walker!"). This ensured that they would not only not forget the story, but that they also would be able to tell it completely and faithfully when their time came to tell it to the next generation as the teller admonishes them to do as per the ritual. The film's director uses that ritual effectively, first to introduce Max (and us) to the story of how they had gotten to that hidden canyon, and then at the end to how they were going to keep alive the history of how Max had delivered them to a new promised land:

   Time counts and keeps countin', and we knows now finding the trick of what's been and lost ain't no easy ride. But that's our trek, we gotta' travel it. And there ain't nobody knows where it's gonna' lead. Still in all, every night we does the tell, so that we 'member who we was and where we came from... but most of all we 'members the man that finded us, him that came the salvage. And we lights the city, not just for him, but for all of them that are still out there. 'Cause we knows there come a night, when they sees the distant light, and they'll be comin' home.

2. In the opening of Dragonslayer, we see the old wizard preparing a potion, during which he mutters a number of incantations and makes a number of gestures in what seemed to be an absent-minded manner. That wasn't just superstition, but rather he was preparing that potion in exactly the way he had been taught, so that he wouldn't leave anything out. Making the incantations and gestures were sort of like running through a checklist. Indeed, running through a pre-operational checklist is a form of modern ritual for pilots and technicians -- Air Force technicians virtually live by the check-list -- which serves exactly the same purpose. Of course, that ritual must always be performed mindfully -- some airline crashes have been due to pilots getting lax and just giving lip service to the checklist without mindfully doing and verifying those actions (eg, setting flaps before take-off thus not having enough lift to get off the ground).

Other such lists exist on-line.

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The Cranial Nerves

First mnenomic device first, since it was mentioned above as a motivation for starting this list.

The cranial nerves are:

1. Olfactory nerve
2. Optic nerve
3. Oculomotor nerve
4. Trochlear nerve
5. Trigeminal nerve/dentist nerve
6. Abducens nerve
7. Facial nerve
8. Vestibulocochlear nerve/Auditory nerve
9. Glossopharyngeal nerve
10. Vagus nerve
11. Accessory nerve/Spinal accessory nerve
12. Hypoglossal nerve

Note that nerves V, VIII, and XI can have one of two different names which would be represented by a different letter in the mnemonic. This allows for more flexibility in devising mnenomic devices for them.

The old standard that we have all heard referenced comes in variations which exploit the different names for some of the nerves:

On Old Olympus' Towering Top, A Finn And German Viewed Some Hops
On Old Olympus' Towering Top, A Friendly Viking Grew Vines And Hops

Note that the first one uses Nerve VIII's name, "Auditory nerve", and Nerve XI's name, "Spinal accessory nerve", whereas the second uses their names "Vestibulocochlear nerve" and "Accessory nerve", respectively.

There are many more, which I found listed at SCRIBDB's List of mnemonics for the cranial nerves. That page also lists mnemonics for the nerves' functions (sensory, motor, or both) and for their skull foramina (plural of foramen, the holes in your head that the nerves go through), as well as links to mnemonics pages for other anatomic features.

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Roy G Biv
Richard Of York Gave Battle In Vain    (British version from Ghosts)

The colors of the rainbow in the order of their appearance: red, orange, yellow, green, blue, indigo, and violet.

Neil deGrasse Tyson said that there are actually only six colors in the spectrum, but Newton inserted indigo because he wanted there to be seven colors -- some kind of numerological significance, apparently. For that matter, he could have added any number of intermediate colors between the other primary colors, since the rainbow is a continuous spectrum.

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Bad Boys Run Over Yellow Gardenias Behind Victory Garden Walls.
Bad Boys Rape Our Young Girls But Violet Gives Willingly.

In electronics, the resistance value of resistors is marked by colored bands:

Color	1st Band (100s)	2nd Band (10s)	3rd Band (1s)	4th Band (Multiplier)
Black	0	0	0	1 Ω (100)
Brown	100	10	1	10 Ω (101)
Red	200	20	2	100 Ω (102)
Orange	300	30	3	1 kΩ (103)
Yellow	400	40	4	10 kΩ (104)
Green	500	50	5	100 kΩ (105)
Blue	600	60	6	1 MΩ (106)
Violet	700	70	7	10 MΩ (107)
Grey	800	80	8
White	900	90	9

So then a resistor marked with black, yellow, violet, and orange would have a value of 47 kΩ. A table explaining resistor color codes is at http://www.elexp.com/t_resist.htm.

I had also encountered some older capacitors and other electronics components that also employed a similar color code.

I would also like to point out that the color codes for the digits 2 through 7 are the same colors in the same sequence as the colors of the rainbow given above (ie, ROY G BIV), though excluding indigo (which arguably was added only to serve Newton's numerological sensibilities that there should be seven colors instead of only six). That made it somewhat easier for me to memorize the color codes: "Black, brown, ROY G BV, grey, white."

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Thirty days hath September,
April, June, and November;
All the rest have thirty-one
Excepting February alone:
Which hath but twenty-eight, in fine,
Till leap year gives it twenty-nine.

How many of us still chant some version of this one to ourselves whenever we need to figure out the date of the end of the month?

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In 1492, Columbus sailed the ocean blue.

Just imagine what would have happened if he had waited another year. For that case, I've heard someone suggest, "In 1493, Columbus sailed 'cross the sea." But that just wouldn't have had the same ring to it.

BTW, 1492 has greater significance. That was the year that the Spanish finally pushed the Moors out of Spain, ending centuries of war. The sudden outbreak of peace freed up resources so that they could finance Columbus' expedition, though this time also marked the expulsion of the Jews from Spain, the forced conversion to Catholicism of those who chose instead to remain, and the institution of the Spanish Inquisition to verify the sincerity of those who converted. 1492 was a very busy year for Spain.

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Divorced, beheaded, died.
Divorced, beheaded, survived.

For remembering the fates of King Henry VIII's six wives.

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A J Squared Away

This was taught in the US Navy DP school for memorizing the punch-card Hollerith codes for the alphabet:

A through I -- Numerics 1-9 respectively in Zone 12
J through R -- Numerics 1-9 respectively in Zone 11
S through Z -- Numerics 2-9 respectively in Zone 10

More information on punch cards has been compiled by Douglas W. Jones of the University of Iowa Department of Computer Science and can be found on his Punched Cards page. The codes themselves are discussed on his Punched Card Codes page.

When I was studying computer science, our school used an IBM S/370 mainframe, so I learned EBCDIC (Extended Binary Coded Decimal Interchange Code). When I later learned Hollerith codes I immediately noticed that they were laid out very similarly if you take the first four bits of the character code to function like the Hollerith zone. That should come as no surprise since Herman Hollerith's 1898 company based on punch-card technology merged in 1911 with three other companies to form Computing-Tabulating-Recording Company (CTR), which was later renamed to International Business Machines (IBM). For the first half of the 20th Century IBM dominated the data processing industry with its punch-card technology. After WWII, IBM resisted joining the new computer industry until a change of management in 1952.

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ELI the ICE man --

Voltage (E) leads current (I) in an inductive (L) circuit.
Current (I) leads voltage (E) in a capacitive (C) circuit.

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Easy as PIE.

In electrical theory, the formula for power is P = E * I , power equals voltage times current.

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The Arrow Points iN.

In semiconductor electronics, devices consist of N-type materials (ie, the crystal lattice contains extra electrons) and P-type materials (ie, the crystal lattice contains fewer electrons, AKA "holes"). In a device's schematic symbol, the arrow points to the N-type material.

Pure semiconductors (eg, germanium, silicon) form a crystal lattice in which every valence electron is shared with a neighboring atom so that that crystal acts as an insulator; there are no free electrons nor any free place for electrons to flow. To become a conductor, the semiconductor crystal must be doped with impurities that replace some of the semiconductor atoms in the crystal lattice, causing that crystal lattice to have either have extra electrons (N-type) or too few leaving "holes" (P-type). The impurities I was taught about would be Indium for N-type and boron for P-type. Both N-type and P-type semiconductor materials act as conductors. Fuse an N-type material with a P-type material (as in a diode) and their junction will become electrically neutral and hence an insulator. Apply a negative voltage to the N-type material and a positive to the P-type and you forward bias that junction which will shrink and allow current to flow through it. Apply a positive voltage to the N-type material and a negative to the P-type and you reverse bias that junction which will increase its size and keep current from flowing through that junction. That is the fundamental basis for how semiconductor devices work.

Here is the schematic symbol for a diode:

The arrow points to the N-type material, which is the cathode.

Here is the schematic symbol for an NPN bipolar junction transistor:

The arrow points to the N-type material, so the emitter is N-type material. It should also be noted here that in bipolar junction transistors the arrow is associated with the emitter-base junction.

Here is the schematic symbol for a PNP bipolar junction transistor:

The arrow points to the N-type material, so this time it's the base that's the N-type material.

You can extend this to dealing with MOSFETs and determining whether they are N-channel or P-channel devices.

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Flower Children Get Dumber After Every Bummer

In music theory, the order of sharps in a key signature: FCGDAEB.
The order of flats is simply reversed: BEADGCF.
The same patterns repeat themselves in the Circle of Fifths for both major and minor keys (see also here), such that you can read off the major key for a given key signature by going two to the right and the minor key by going five to the right (or two to the left) -- you can also work out the flats by working backwards on the Circle:

F C G D A E B
Sharps	Flats	Major Key	Minor Key
	B E A D G C F	C-flat	a-flat
	B E A D G C	G-flat	e-flat
	B E A D G	D-flat	b-flat
	B E A D	A-flat	f
	B E A	E-flat	c
	B E	B-flat	g
	B	F	d
		C	a
F		G	e
F C		D	b
F C G		A	f#
F C G D		E	c#
F C G D A		B	g#
F C G D A E		F#	d#
F C G D A E B		C#	a#

Other versions I have encountered:

• Fast cars get driven away, even Buicks
• Fat Cats Go Down Alleys Eating Birds.
• Fat Cats Get Dandruff And Eat Beans
• Fat Cats Get Drunk After Eating Beans.

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Every Good Boy Deserves Favor (or, Every Good Boy Does Fine)
FACE
All Cows Eat Grass

In music theory, these represent respectively:

• the notes of the treble (G) clef: the lines (EGBDF) and the spaces (FACE).
• the spaces on the base (F) clef: ACEG

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The woman is always right and the guy gets left behind.

In every partner dance I've encountered so far, the man's first step is always with the left foot and the woman's with the right.

I also use this rule to keep straight which of the two drinks I'm carrying is mine and which is my wife's companion's.

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Kick right in or be left outside.

This is one that I made up for a number of steps in Lindy where the couple both kick forward at the same time while facing each other in very close closed position; eg, flash kicks, a kicking turn in Charleston, cake walk. Needless to say, if you or your partner kick in the wrong place, a shin is going to get hit.

What this one means is that your right foot kicks between your partner's legs and your left foot on the outside. I haven't encountered any exceptions to this rule in Lindy. I also have not encountered these kinds of kicks in other dances, so I'm not sure it applies to them.

BTW, by following the basic rule of offsetting yourself from your partner a bit to your left while in closed position, these kicks tend to work themselves out naturally.

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Programmers Do Not Throw Sausage Pizza Away

In computer networking, the OSI protocol stack consists of seven layers, from the bottom up:

Physical, Data-link, Network, Transport, Session, Presentation, Application.

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My very earnest mother just served us nine pickles
My Very Educated Mother Just Sent Us Nine Pizzas
    also
Mark's violet eyes make Jane sit up nights pining.
        (contributed)

The names of the planets in the Solar System, in order from the Sun out:

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto

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Oh, Be A Fine Girl, Kiss Me.

In astronomy, the order of the spectral classes of stars in the Russel-Hertzsprung diagram:

O, B, A, F, G, K, M.

The Sun is a class G star.

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Kids Pour Catshup Over Fat Green Spiders.
    also
Kindly Purchase Cookies Only from Girl Scouts
        (contributed)
    also
Kings Play Chess On Fine Grain Sand
        (contributed)

From biology, the Linnean classification system:

Kingdom, Phylum, Class, Order, Family, Genus, Species.

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Cows often sit down carefully, perhaps their joints creak.

The geological ages:
  Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous

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How Many New Airmen Will Get Sex Free?

As taught in US Air Force basic training, the organizational structure of the Air Force:

• Headquarters, USAF
• Major Air Command
• Numbered Air Force
• Wing
• Group
• Squadron
• Flight

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Be My Little General.

In the Army, Air Force, and Marine Corps, the ranks for general, in ascending order (one-star to four-star):

1. Brigadier General
2. Major General
3. Lieutenant General
4. General

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Starboard is more to the right than port.
        (contributed)

Equating the letter "r" with "right", starboard with its two "r's" is more "right" than port is with but a single "r".

The basic rule is that starboard is to the right when you are facing the bow (front) of the vessel. It is important to note that you need to be standing on the vessel when applying this rule. I once got into an argument over this with a friend who insisted that I had it turned around. As it turned out, he was applying the rule while standing (mentally, of course) in front of the ship instead of on it.

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Port wine is red.

A vessel's port running light is red and the starboard light is green.

During one CPO initiation, the selectees were required to modify their running shoes with red shoelaces on the left shoe and green on the right.

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The heart is on the left.
Blood is red and so is port wine.

This is a more complicated mnemonic for the previous two rules:

• Port is to the left, the same side as the heart.
• The port running light is red, the same as blood and port wine.

This one was taught to me by a friend's mother who had gotten it from her aunt. What amazed her about it was that her aunt, a staunch advocate of temperence, would even make reference to wine.

And, yes, I know that the heart isn't actually on the left; it's centered in the chest and beats more strongly to the left, which is why we feel it there more. I plead poetic license here.

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Face is red, raise the head.
Face is pale, raise the tail.

These are two rules of thumb in First Aid for deciding which end to elevate. The second one is for treating shock (the face is pale because the blood isn't getting to the head).

Be sure to first receive proper First Aid training before applying either of these rules. There's no substitute for knowledge and proper training. Basic rule of thumb for "Good Samaritan" laws: Never attempt anything that you have not been trained to do. IOW, if you don't know what you're doing then do not attempt it.

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Please excuse my dear aunt Sarah. (P E M D A S)

I just now saw this one on the Netflix series, Ozark (Season 3, Episode 2, beginning of the episode where this mnemonic is offered by a substitute teacher in algebra class).

A key concept in algebra is the order of operations -- a concept which carries over into many programming languages whose basic syntax is algebraic. There is a natural precedence of operations, of which operations are to be performed before others, though that can be overridden by grouping symbols such as parentheses. This mnemonic establishes that order of precedence, of the exact order in which operations must be performed when evaluating an expression:

• P -- Parentheses. Algebra has many grouping symbols, so in that environment you can go pretty deep. In programming languages, all you have are parantheses. I've seen LISP programs with so many levels of parentheses as to boggle the mind.

  The main point of groupings symbols (which always come in nested pairs) is that they have precedence over all other operations. And also, all other precedence outside of grouping symbols must follow natural precedence. As is given below.

  BTW, one of the grouping symbols is the numerator/denominator bar of a fraction. Everything in the numerator is grouped together, as is everything in the denominator.

• E -- Exponent. The next operation is raising to a power. That would also include fractional exponents, AKA "taking roots." So an exponent of 0.5 is taking the square root.

  Therefore, raising to a power or taking a root are both at the same precedence.

• M -- Multiplication.

• D -- Divide. Actually, this is at the same precedence as multiplication, but it's often more convenient to multiply before dividing.

• A -- Add.

• S -- Subtract. Again, the same precedence as addition.

 

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"Can I have a small container of coffee?"

This is a mnemonic for memorizing the first eight (8) digits of pi (π): 3.1415926 . Simply count the number of letters in each word. The WikiQuotes English mnemonics page (link broken) calls this practice "Piphilology".

I heard it the one night on an NPR game show program, "Says You" I think it was. One of the panelists commented, "Well of course, coffee does go well with pie."

I also found it at a Zimaths page which lists other such mnemonics for pi in several different languages (again, unfortunately, link broken). Two more in English are:

• How I wish I could enumerate Pi easily, since all these horrible mnemonics prevent recalling any of pi's sequence more simply.
  and
• How I want a drink, alcoholic of course, after the heavy chapters involving quantum mechanics. One is, yes, adequate even enough to induce some fun and pleasure for an instant, miserably brief.

To 32 digits. Wow.

Also on that page with the broken link is a short story that gives the first 402 digits of pi.

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First uploaded on 2001 October 05.
Updated on 2021 April 02.