0992: "Mnemonics"

[StuartP]

Part of doing a chemistry subject at uni (a filler subject in a science degree) was a requirement to learn part of the periodic table (Hydrogen, Helium, Lithium etc).

Here was my slightly weird attempt at memorising it:

Harry, He Likes Beer But Can Not Open Fosters - Never mind, Nancy hands over a Mug

(Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Flourine, Neon, Sodium(Na), Magnesium)

(Fosters = Australian brand of beer)

[scarletmanuka]

I agree it should be avoided, but BODMAS gives us a definite order or precendence for it.

Except that it doesn't. This is demonstrated by replacing division with multiplication and vice versa.
10 / 5 * 2 --> 10 * .2 / .5
If division took precedence over multiplication, the result would be 1 instead of 4. So multiplication and division must always be done left to right.

How do you get that? 0.2 / 0.5 = 0.4 and 10 * 0.4 = 4.

If you have a chain of multiplications and divisions, doing them all left-to-right will give you the same result as doing the divisions first (in left to right order) and then doing the multiplications. So it doesn't matter which of those two systems you use, as long as you use it correctly. Personally I'd expect the first way to be easier to learn and to execute correctly, but that may just be bias due to having learned it that way myself.

[rodneyAnonymous]

Do kids prefer Coke over Fanta grape soda? Domain kingdom phylum class order family genus species.

[Smoli]

At school (in the UK) in the '90's, I learned the planets by: "My Very Easy Method Just Speeds Up Naming Planets...!"

No asteroids or accounting for trans-Neptunian controversy though...! :/

[mootown2]

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.

I teach high school mathematics and I tell my students that "PEMDAS" is for middle schoolers - GSERMDAS is a more accurate mnemonic for:

Order of Operations:
1. Grouping Symbols (innermost first)
2. Exponents/Radicals
3. Multiplication/Division from left to right
4. Addition/Subtraction from left-to-right

I personally like it because each level of priority gets two letters, but I'm sure most of my students who need a mnemonic still think PEMDAS to themselves.

And yes, "Division & Multiplication" in that order did bother me, but I didn't honestly notice it until a former student pointed it out when I posted a cropped version of the image ...

EDIT: Also forgot to mention that the two operations per level helps stress inverse operations - generally, you evaluate expressions (arithmetic) going down order of operations, but you solve equations (algebra) by reversing order of operations .... I call this the "Socks-and-Shoes Rule" ... hopefully some of this makes them better at mathematics

[Richard Kirk]

Make them rhyme...

Chant the Ordered Sequence Downward
Cambrian to Present Time
Just in Case Past Eons' Order
May be Put from Prose to Rhyme

Only the capitals are used; we have 'Recent' instead of 'Holocene', and the Paleocene (Past) mucks up the scansion. Can you fix it?

[flyingcow93g]

I registered just to say this.

Big Bears Run Out Yelling 'Go Buy Vintage Goose Whistles!!'

[rodneyAnonymous]

How do you remember that "Big Bears [...] Buy" is not, say, blue-black-brown? Or tell the B's apart in any of these mnemonics for resistor colors, I guess.

[flyingcow93g]

It goes from darker to lighters. Black, Brown, ect.

[poofyfifi]

A good one for carbon chain prefixes is: My Elderly Parents Beat Poor Helpless Hopeless Orphans Near Death.
Methyl-, Eth-, Prop-, But-, Pent-, Hex-, Hept-, Oct-, Non-, Dec-

[mixh]

Given Marx's general impecunious state and reliance on industrialist buddy cooking books, I think coming up with Zeppelins is a little unlikely: "Karl Marx Got Twenty Pounds Engels Zeroed Yearly".

[Kichigai]

My "new" favorite mnemonic for the planets is from The Colbert Report, specifically right when it was announced that Pluto was being downgraded to a Dwarf Planet:

"My Very Educated Mother Just Said, 'Uh-oh! No Pluto!'"

[Socks]

... and that's why y'all should switch to Polish Notation. No ambiguity, easy to program with, and understood by nobody

There was an excellent SOH-CAH-TOA song that I heard many many years ago in a folk/hippy style. Can't find it. But I learned this sin/cos memory trick from an excellent high school physics teacher: "Father Sine, Holy Cos". Cross yourself while reciting this trig prayer and you have the axes for each!

I actually showed my work once like that on a math exam (after a few nights without sleep, and far too much LISP programming). The prof put question marks, then crossed them out and wrote a smiley face next to my work. Once you work like that for a while, it makes total sense.


Also, on the pi discussion, I'm firmly in the easily-remember-number-strings category (3.1415926535897932384626433832 from memory. I actually had it up to 60+ digits at one point. We had a competition, and I won an apple pie?. )

[lgw]

The next person to post the old, shitty misogynistic (and intermittently racist) resistor code like they're being adorably transgressive or otherwise wax excited about it is going out the door.

Wow, I had no idea this forum was so obsessively ...Hold on, I think I swallowed a gerbil. Okay. What was I saying?. I feel regret and sadness for ever posting here.

[dchmello]

When I was an Electrical Engineering student, I also learned the profane mnemonic for resistor colors. A professor taught the following, though:

B.B. Roy, Great Britain, Very Good Worker

Wasn't as helpful as the other, but at least I had a clean one to keep in mind.

[gmalivuk]

I feel regret and sadness for ever posting here.

Your absence will not be noticed.

[stephenhfoster]

Geologic mnemonic for Paleozoic: "Can our sly dog miss pet practice?" My field partners came up with that one.

[krollipop]

For trigonometric identities, trust a class of 25 hormone filled adolescents to come up with:

Sex On Horseback Can Actually Happen To Our Amazement

Never again will the class be asked for suggestions...

[soren121]

It's supposed to be NINE PIZZAS.

[MicroPaleontologist]

I'm a geologist and I study that! (Points at ground)

I was once told a mnemonic for the paleozoic:
Campbell's Onion Soup Does Make Peter Pale
Cambrian Ordovician Silurian Devonian Mississippian Pennsylvanian Permian

*The Carboniferous is usually split up into the Mississippian and Pennsylvanian

[ellenmaclean]

My partner, who was tutoring high-school students at the time, always used:

Keep Putting Condoms On For Great Sex

for

Kingdom Phylum Class Order Family Genus Species

I liked that it was simple and served the double purpose of science memorization and "safe sex reminder". Also, it certainly seems to stick in the students minds.

[Hotchy]

About 30 years ago, our lecturer gave us this vintage mnemonic from his generation of valve circuit designers:
Best Be Ready Or Your Grid Bias Voltage Goes West.

Of course, that was offered as a ...Hold on, I think I swallowed a gerbil. Okay. What was I saying? alternative to the rude one, and aren't rude mnemonics the only ones worth remembering?

[ConMan]

For trigonometric identities, trust a class of 25 hormone filled adolescents to come up with:

Sex On Horseback Can Actually Happen To Our Amazement

Never again will the class be asked for suggestions...

Funnily enough, a book I read once suggested "Sex On Holidays Can Advance Happiness To Outrageous Amplitudes".

[OBloodyHell]

Canadian provinces:
MS-ABC (as opposed to the Lefty news channel)

Manitoba, Saskatchewan, Alberta, British Columbia

Also, on the pi discussion, I'm firmly in the easily-remember-number-strings category (3.1415926535897932384626433832 from memory. I actually had it up to 60+ digits at one point. We had a competition, and I won an apple pie?. )

I have always had it to 25, can never seem to reliably keep more than that. Considering that's sufficient for a 3 foot error in calculating the circumference of the known universe, it's good enough for ballpark calculations on the backs of envelopes...

I first learned it back in 1974, when a friend of mine decided he was going to get into Guiness BoR which listed 700 digits as the record. He had it memorized up to 1000 digits by the time the next edition came out, when it was upped to 2000 digits. He gave up.

[Kaiman]

I fondly remember one of my math teachers giving us a mnemonic for sine cosine and tangent as "Some Old Hippie Caught Another Hippie Tripping On Acid."

As a math tutor, I can vouch that this IS the best way to remember it. Saying "Sohcahtoa" as one long word isn't nearly as effective.

Also, on the pi discussion, I'm firmly in the easily-remember-number-strings category (3.1415926535897932384626433832 from memory. I actually had it up to 60+ digits at one point. We had a competition, and I won an apple pie?.

e is so easy to remember to 15 digits.
"2.7" = 2.7
"Two Andrew Jacksons" (he became president in 1828) = 18281828
"equilateral right triangle" = 459045

Not that many people even in the USA know from memory that Andrew Jackson's tenure in office started in 1828, but the main is that the same 4 digits happen twice which makes it easier to memorize.

[bmonk]

Canadian provinces:
MS-ABC (as opposed to the Lefty news channel)

Manitoba, Saskatchewan, Alberta, British Columbia

Also, on the pi discussion, I'm firmly in the easily-remember-number-strings category (3.1415926535897932384626433832 from memory. I actually had it up to 60+ digits at one point. We had a competition, and I won an apple pie?. )

I have always had it to 25, can never seem to reliably keep more than that. Considering that's sufficient for a 3 foot error in calculating the circumference of the known universe, it's good enough for ballpark calculations on the backs of envelopes...

I first learned it back in 1974, when a friend of mine decided he was going to get into Guiness BoR which listed 700 digits as the record. He had it memorized up to 1000 digits by the time the next edition came out, when it was upped to 2000 digits. He gave up.

Yes, and 3.1415926 will give you the circumference of the earth to within a half meter, which should be good enough for all practical purposes. . . .

But it doesn't do much for geek bragging rights.

[Kisama]

My female circuits teacher taught us "bad boys race our young girls but violet generally wins."

I always thought circuits were gender neutral.

[Red Hal]

My female circuits teacher taught us "bad boys race our young girls but violet generally wins."

I always thought circuits were gender neutral.

For some unfathomable reason I now have an image of the cover of a book entitled "Harry Potter and the circuits of gender", by JK Flip-Flop

[Kit.]

e is so easy to remember to 15 digits.
"2.7" = 2.7
"Two Andrew Jacksons" (he became president in 1828) = 18281828
"equilateral right triangle" = 459045

Not that many people even in the USA know from memory that Andrew Jackson's tenure in office started in 1828, but the main is that the same 4 digits happen twice which makes it easier to memorize.

It's easier for Russians. 1828 is Leo Tolstoy's birth year.

[gmalivuk]

Canadian provinces:
MS-ABC (as opposed to the Lefty news channel)

Manitoba, Saskatchewan, Alberta, British Columbia

And for the other 8?

[eran_rathan]

Canadian provinces:
MS-ABC (as opposed to the Lefty news channel)

Manitoba, Saskatchewan, Alberta, British Columbia

And for the other 8?

What other 8 - everyone knows that REAL Canada starts in Manitoba. Ontario and the rest of them are just poseurs.

[Adabillius]

The geologic one is way too hard. How about something like:
People Can Order Spaghetti Dinner Carefully, Permitting That Jackalopes Can Prance Nightly;
or, Placing Cookies On Sweet Dark Chocolate Pieces Tastes Juicy, Can Please Nightly
(Precambrian Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleogene Neogene)

[UncleJeremy]

Well, I learned the profane version of the "Bad Boys" mnemonic in 10th grade electronics class from the teacher. This was in 1970. Yes it is sexist and mean, but boy I sure to remember how to read the color coding of resistors!