0992: "Mnemonics"

[doubletwist]

The one I learned for resistor color-codes was a bit less vulgar than the typical one:
"Bad Beer Rots Our Young Guts, But Vodka Goes Well. Get Some Now"

[Timothyf]

In decreasing order of pKa: RIghteous Kings Hear Dames Ejaculate (You Can't). Honorary charged amino acids in parentheses.

Major anions: Bob's Car Nailed Chloe, Pending Suspension

Dirty mnemonics are always easier to remember.

[Wesley Foxx]

See, I still prefer my high school animal classification mnemonic.

Kangaroos Play Chess On Fuzzy Green Squares.

[UniqueScreenname]

I have a Zune...

[adhair]

I learned PE(MD)(AS), with MD and AS being left-to-right, but mostly not to introduce ambiguity if you can help it.

[dnl42]

Sailors know these to enable conversion among compass, magnetic, and true headings

Can dead men vote twice at election

Compass heading, add Deviation to get Magnetic, add Variance to get True, Add East

From True heading, add Variance to get Magnetic heading, add Deviation to get Compass heading

Timid virgins make dull companions

That first one is especially for Massachusetts and Illinois readers :p

[Yoduh]

I agree it should be avoided, but BODMAS gives us a definite order or precendence for it. (As does BO(DM)(AS), which is what you're familiar with). The same goes for 10 - 5 + 2.

10 - 5 + 2 would equal 7 no matter what order you do it in. If you add 5 + 2 to get 7 then subtract that from ten, you've added in a bracket, changing the problem to 10 - (5+2). As long as the numbers keep their signs attached, adding and subtracting can be down in any order, left to right (I.E. -5 + 2 = -3, 10 - 3 = 7).

a sign outside a bracket is applied to each number within, such as -(5x+7) = -5x-7. In the case of 10 - (5+2) it becomes 10 - 5 - 2, which performed left to right = 3. Which is also the answer you would expect from following BODMAS since you've introduced brackets, 10 - (7). So yes it does matter what order you perform DM/AS when there are no brackets to specify (a practice which should be avoided anyways).

[The Moomin]

For sin, cos and tan we had a mnemonic that only really worked for having been taught by Ms Andrews: Oh Heck, Another Hour Of Andrews.

For planets I was taught: Many Vegetarians Eat Mucky Jam Sandwiches Under Nude Pictures.

I also got taught the mnemonic MRSGREN, but I'm not 100% sure what it is for. I think the M is for movement, and one of the Rs is for respiration?
*Turns out it's a mnemonic for the seven qualities all living things possess.

EDIT: We also got taught BODMAS in middle school, but as our teacher was called Bob, we changed it to Bobmaths so it lost any real meaning.

[Keiji]

When I was a kid and Pluto was still a planet, I was taught "My Very Efficient Memory Just Stores Up Nine Planets".

I always liked to think it remembered more than just that, but oh well...

I also learnt the "**triggery misogyny not found**" one at school, though I was too immature to understand the latter clause of that sentence at the time, and I hadn't seen it since until now...

As far as giving SOHCAHTOA a mnemonic, who needs one? It's easily pronounceable by itself. http://www.youtube.com/watch?v=vfQXSIpzYJo

[wolftune]

A guideline people often miss about mnemonics: It's important that the sentence has to go the way it does, otherwise it risks mix-up.

"People Expect More Drugs And Sex" fails to meet this guideline because you could erroneously remember it as "People Expect More Sex And Drugs"

Mnemonics should never use lists that can be rearranged!

[Timothyf]

Come Over SunDay, Maybe Play Poker, Three Jacks Cover Two Kings.

Oops, make that Two Queens.

[SEE]

For some actual pedantry, the Great Lakes west-to-east is not the same as the paddle-to-the-sea order. If you start on Superior, you go on St. Mary's River directly to Lake Huron, skipping Lake Michigan entirely.

(Michigan and Huron are hydrologically and hydrodynamically one two-lobed lake, while Nipigon is a pretty big lake that drains into Superior, and the smallish but important Lake St. Clair is between Huron and Erie.)

[VectorZero]

I'm curious as to the need for anyone other than stoned first year philosophy students to need to memorise the characteristics of life ...

Though to be fair it probably has slightly more application in day to day life then remembering the order of the planets.

[AdmiralJota]

A couple years ago, I came up with this one for the planets:

Many Very Educated Men Consider Juvenile, Smaller, Unimpressive New Planets Hardly Mentionable Entities

I'm sure one could improve on it, but I'm surprised that I haven't seen many others like it.

[The Moomin]

I'm curious as to the need for anyone other than stoned first year philosophy students to need to memorise the characteristics of life ...

Though to be fair it probably has slightly more application in day to day life then remembering the order of the planets.

It was taught in a Biology class when I was 15-16 years old I think. So it probably has exactly the same amount of application as knowing the order of the planets, except it would be in Biology classes and not Physics classes.

[dado]

Oups! I made amistake: it's plural, which means au"x" sage"s" . Thak you for poiting this out adhair, i should double check
pi is then 3,1415926535

So much for more memory than my calculator

[Magnusian]

As I was taught in college:
Bad Boys Race Our Young Girls But Violent Generally Wins.

As I was taught by EE father:
**triggery misogyny not found**.

The first one doesn't seem all that inappropriate. I've seen a version that uses "Big Boys" but the point of Bad Boys is the second letters help you know the order is Black and Brown, B(l)a, B(r)o so the "Big Boys" version makes little sense to me. Never seen the version of the second one with "Gives" before seeing this thread. Honestly though, the second is more memorable and people should just get over themselves. What's more important? Remembering something or making people feel good about themselves?

My one for planets:
Man Very Early Made Jars Stand Up Nearly Perpendicular, which I guess doesn't work anymore because of those Pluto-hating jerks.

[zeehio]

At first I thought, "how is it that Randall Munroe did not account for the "Multiplication/Division" order in the strip?"
Then I realized that the symbol used between "division" and "multiplication" accounts for shifting, as well as the "Addition" "Substraction" and others.

He is really good.

[Anju]

I learnt the planets as "my very earnest man just showed us nine planets", which has the advantage of making it obvious what it's for. I always forget what the adjective is though, and it doesn't work without pluto The one for the compass points was "never eat soggy weetbix".
My chemistry teacher taught us "monkeys eat pealed bananas" for meth-, eth-, prop-, bute- in organic chem.

[VectorZero]

@AdmiralJota: I like that. A much better option.

@The Moomin: Well, if we are around for the technological singularity, you'll be able to tell me if our new robotic overlords are alive or not

[robarm]

Come Over SunDay, Maybe Play Poker, Three Jacks Cover Two Kings.

Thank you Dr. Siddoway, Professor of Geology, Colorado College.

The one I learned in college for the geologic eras is:

Can Oscar See Down My Pants Pocket? Tom Jones Can, Tom's Queer.

That gets you from Cambrian to Quartenary

[johnkmt]

i think it should be Damn Katy Perry... and, us diggers-in-the-dirt will keep making changes in taxonomy every day we go to work. i love a wide-open field!

[Shadowtail24]

I volunteer in a 5th grade classroom and I learned the other day that PEMDAS is now GEMDAS (Grouping, etc). GEMDAS is much harder to mnemonize.

[Andromeda321]

My favorite two are missing:

For star types, ie OBAFGKM
Traditional: Oh be a fine guy/gal kiss me

that was posted.

He forgot the classic stellar classification mnemonic. O, B, A, F, G, K, M, and later R, N, S were added.

Traditional: Oh, be a fine girl/guy, kiss me right now honey.

I was referring more to the silly non-traditional mnemonic I posted afterwards of "only boys accepting feminism get kissed meaningfully." Sorry if that wasn't clear.

[Deenreka]

I agree it should be avoided, but BODMAS gives us a definite order or precendence for it. (As does BO(DM)(AS), which is what you're familiar with). The same goes for 10 - 5 + 2.

10 - 5 + 2 would equal 7 no matter what order you do it in. If you add 5 + 2 to get 7 then subtract that from ten, you've added in a bracket, changing the problem to 10 - (5+2). As long as the numbers keep their signs attached, adding and subtracting can be down in any order, left to right (I.E. -5 + 2 = -3, 10 - 3 = 7).

a sign outside a bracket is applied to each number within, such as -(5x+7) = -5x-7. In the case of 10 - (5+2) it becomes 10 - 5 - 2, which performed left to right = 3. Which is also the answer you would expect from following BODMAS since you've introduced brackets, 10 - (7). So yes it does matter what order you perform DM/AS when there are no brackets to specify (a practice which should be avoided anyways).

Order wouldn't matter, because by adding 5 and 2 without keeping the negative sign attached to the five, you have added in brackets. Order doesn't matter when you keep signs attached. The mistake in adding 5 and 2, then subtracting that from 10 comes from separating the sign from the number. To put my argument into phrase, there is no subtraction, only addition of negative numbers (Also follows from this that there is no division, only multiplication of fractions). Therefore, BODMAS should be BOMA.

[Steve K]

PEMDAS sucks because:
it implies multiply and division have different precedence, when they're actually the same, likewise addition subtraction
Grouping is the highest precedence and either the American P version or the Brit B version omit a vertical division bar, which is a significant group operator. e.g.
8
2Pi
is 8/(2Pi), not 8/2 * Pi, a common student mistake

Actually,

Code: Select all

8
-
2Pi


is a typographic error, as the division bar is not over Pi. As intended, it should be written:

Code: Select all

8
---
2Pi


to distinguish it from

Code: Select all

8
-Pi
2


which is how many people read the given example.
On a side note, I'm surprised no-one's mentioned my favorite mnemonics thus far, LDDR and LDIR.

[Tirian]

As far as giving SOHCAHTOA a mnemonic, who needs one? It's easily pronounceable by itself.

At the same time, I've tutored students who don't recall if it's SOHCAHTOA or SAHCOHTOA. (Perhaps Randall has too.) Like someone previously said, mnemonics are supposed to unambiguously give us the right order, which is why I teach Some Old Horse Caught Another Horse Taking Oats Away.

[Novamystique]

Another mnemonic: Circle of Fifths (F, C, G, D, A, E): Fred Calmly Goes Down And Eats Boobs.

(Thank you Rick Hip-Flores for asking us to create our own mnemonics and then share them with the Sight Singing class.)

[transversality]

I've found the following a helpful way to remember the geologic time scale, set to the tune of the Major-General's Song (also used for Tom Lehrer's The Elements):
There's Cambrian, Ordivician, Silurian, Devonian,
and Mississipian and Pennsylvanian and Permian,
and Triassic and Jurassic, Cretaceous and Paleocene,
and Eocone, Oligocene and Miocene and Pliocene.

Note that, in the interest of scansion, I've broken up the Carboniferous period into Mississippian and Pennsylvanian sub-periods (common usage in North America), and also I've descended to the epoch level from the Paleocene on.
But, aw heck, I've just wiki'd the correct pronunciation of Ordivician /ɔrdəˈvɪʃən/ and it has one syllable less than I thought.
And I know, it's a not a mnemonic.

[ptorquemada]

Omni magazine had a contest for these in the ... early 80s, I think it was; the winners for the SI prefixes were "damn clever mnemonic makes no prefix forgettable" for the ones less than unity, and the (brilliant) "Decadent Hector killed Meg's gigantic terrier" which could be expanded with "pet excellently" to cover the next two for the ones larger than unity.

Both of those are "mnemonics for something you shouldn't need mnemonics for", though. My favorite was "Tall gyroscopes can fly apart, orbiting quickly to complete disintegration" for the Mohs scale, where each word has the first TWO letters correct.

[frieze]

The one I learned was
Bad
Beer
Ruins
Our
Young
Guts
But
Vodka
Goes
Well

[palmwiz]

He forgot the classic stellar classification mnemonic. O, B, A, F, G, K, M, and later R, N, S were added.

Traditional: Oh, be a fine girl/guy, kiss me right now [sweet].

Hubble version: Obviously brilliant astronomer finds galaxies keep moving, revealing new science.

My favorite for this is "On Bad Afternoons Fermented Grapes Keep Mrs. Richard Nixon Smiling". Though I suppose now it would have to be "Kept", not "Keep".

[just john]

I remember the ol' Denial / Anger / Bargaining / Depression / Acceptance sequence thanks to a stand-up comedian whose name I unfortunately forget.

The mnemonic: Drink Alcohol Before Doing Anal

[gmrple]

My favorite way to remember resistor colors was posted on Reddit a couple months back. Sadly I can't find the post at the moment, or I'd give you a direct link

Here it goes:
First you've got two types of bears; Black and Brown, these should be in alphabetical order.

Next you have ROYGBIV (colors of the rainbow), except you have no Indigo, because Inigo is off looking for the six-fingered man. This gives you BBROYGBV.

Finally we have the colors of Gandalf, in chronological order; gray and white. Finally we have BlackBrownROYGBlueVGW.

*EDIT* I found it http://www.reddit.com/r/geek/comments/li9tf/got_an_exam_in_circuits_tomorrow_on_resistors/c2syjf9

[cburke]

Is "nachos" for Neptune already 'traditional'?
Wow, time flies.

[mchrist]

'mstsc'
Traditional: Microsoft Terminal Server Client
Better: Mary Says Tom Sucks Cock

[wst]

The order is PEDMAS (or BODMAS for British readers {brackets, orders, divide, multipy, add, subtract}).

I was always taught BIDMAS, with Indices in the 2nd. Not sure what 'Orders' are, but my (agewise-old) Analytical Methods teacher goes with 'Brackets Of' and many debates ensue thusly.

[Linux0s]

I remember "Every Good Boy Deserves Fudge" for the lines on the treble clef.

[incircuitous]

Hey ptorquemada, I remember that issue of Omni! Several are still in my brain from reading that when I was 12 years old or so:

Men plan many VENUS jumps. (Planets in order of increasing size). Kinda freaky that the word venus is in there. I spoze you could make it 'men make VENUS jumps' to excuse Pluto.

We get tired carrying park rangers (Horse gaits: walk, gait, trot, canter, pace, run)

Wilma's apple jelly makes men adore jam, Vera's hot tamales peel the frying pan... sorry, forgot the rest but that's US Presidents, starting with Washington.

I'M NO WIMP. (states that border the great lakes)

And this nicely self-referential one:

mnemonics neatly eliminate man's only nemesis, insufficient cerebral storage

[Headshrinker]

SOHCAHTOA

Sex On Hard Concrete Always Hurts The Old Arse