Uh…shit…you win.
Originally posted by Ruminator :
“I memorized some of the metric to English conversions.
. . .
2.2 pounds per kilo. . .”
I had a teacher from Japan. I don’t remember what class. He used the word “kilo” and knew that none of us would understand what that was, so he said: “that’s about two pounds.”
But all of us were children of the ‘60’s’ and accustomed to dope measurements.
All of us corrected him in unison: “two point two pounds.”
Jon
Decimal equivalents for common fractions:
7/8 = .875
3/4 = .75
5/8 = .625
1/2 = .5
3/8 = .375
1/4 = .25
1/8 = .125
1/16 = .0625
1/32 = .03125
You get those in your head, you’ll be good for any kind of graphic design/print work. But it applies generally to life in the states every so often. Why oh why didn’t we convert to metric?
Others:
The planets in the solar system and their relative size and distances (bonus points for knowing their moons). Also, being able to spot the 5 or so planets you can see with the naked eye, and knowing just from its brightness which one it is.
The path the sun traces in your local sky for any approximate time of year. Helps you guess at the time of day, and determine which way is north, south, east, west.
Major constellations and stars (and what time of the year they’re visible).
Military time. (I know it’s easy, but most people have to stop and subtract by 12.)
Dates of minor holidays.
How many days in each month (I’m bewildered how many people haven’t memorized this).
Your SS#, driver’s license # and license plate.
Hm. A lot of these don’t seem particularly useful to memorize to me; for many of them, in a world of increasingly-ubiquitous Internet access and concomitant near-instant lookup, it seems like one can get by fine and indeed more productively without wasting time worrying about manual memorization. Could people perhaps explain specifically why their proposals are good ones for memorization?
Names of bones. Not only that, but the ability to pick up a minuscule fragment and be able to identify not only the bone, but the region (anterior, posterior, proximal, distal, etc.), and the side it came from. When you’re working forensics and trying to identify/analyze a skeletonized body, you don’t want to have to be looking up every single bone you come across. Useful for me because of my background in physical anthropology.
I actually think just about any medical facts (like names of bones or common medical prefixes and suffixes) would be useful if just because if you end up getting some sort of disease or injury, then you have some idea of what’s going on in your body.
Which ones? Most of everything posted is something useful to have passing knowledge of so that you can hold an intelligent conversation on a variety of subjects without having to stop and look something up on the internet.
The progression of binary numbers from 4 bits to 8 bits (at the very least for programmers)
Color codes (RGB and CMYK and etc.), if you are a digital graphics designer
I did that for my Latin cases. I can still sing-song the first three at you : Rosarosarosam, rosaerosaerosa, rosaerosaerosas, rosarumrosisrosis ! Hortushortehortum…you get the picture…
The problem is, should I want to know what, say, the genitive plural of the first declension is, I had (and have) to sing all the cases prior to that one, because I learned them all in one bulk rather than individually ;).
I also had the 1-12 times and addition tables drilled into me by a grandmother positively SCAN-DA-LIZED they didn’t do it at school. Boy, did I hate her at the time. Other grandma crimes against Sunday cartoons and fun in general : English and German irregular verbs, French history dates, regions and departments (plus the area code and the main town), European countries & capital cities.
I was spared the weights, measures, trig and log tables though : grandma sucked at science 
Until the day when computers are literally hooked up directly to our brain, a lot of these things are just going to be handy to memorize. Yes, I have my cellphone on me almost all the time, and if I wanted to do some quick arithmetic I could pull it out, find the calculator function, and punch in 12x7. For the time being, however, it’s still a lot easier to just know, instantly, that the answer is 84.
Some of these things are just part of being culturally literate. If you’re reading a book and it mentions something about, say, Oslo, you could put the book down, go to your computer and find out where and what Oslo is. If you’ve committed country capitals to memory, on the other hand, you’ll know that Oslo is in Norway, and at least have some idea what it’s all about. You’ll probably enjoy the book more for it.
We were taught the first 20 elements of the periodic table as a rhyme in grade 9 and I can still roll it off: H Heli Beb CNOF Ne Nam Gal Sips Clark-A
The list of most common letters that I was taught was etaoin shrldum. Useful for playing hangman.
If you’re in a technology industry, the ability to do basic math in powers of two also come in handy. You should have the decimal equivalents of 2^(0-8, 10, 12, 16, 20, 24, 32) memorized at the very least.
Defending the basic multiplication tables and unit conversions:
It’s not that any of them aren’t available through a simple internet search; they all are.
It’s the fact that when you’re actually doing them with real consequences, and maybe two dozen a day, you are far better off being able to spit them out without thought or needing to check on a calculator.
Even more than that, being able to estimate quickly and accurately is incredibly valuable.
When a VP asks you, "Look, we can’t compete unless your suggestion for the formulation adds less than $0.03 / lb. We have 250,000 lbs of product. Is it worth even looking at?
If you say, “Um, well, let me grab my calculator…” you’re dead. You look like a chump. Said VP has already lost interest. Whether the answer is yes or no, any good VP will respect you more if you can look thoughtful for a second or two, and then confidently say “yes” or “no”. You cannot estimate until you can add, multiply, divide and subtract in your head without thought. It needs to be automatic.
Seven Deadly Sins: Greed, Lust, Wrath, Sloth, Envy, Pride, Gluttony.
When I was at the university my roommates and I used to quiz each other on this, our theory was the ones you could not remember, at any given moment, were the ones you were the most guilty of.
Although a Canadian, I have memorized the pledge of aligance. (Hours in a US immigration office with nothing to read, it was painted on the wall!)
Although not Jewish, I have memorized the prayer before the meal. (Spent a summer working at a Jewish camp!)
Assorted poetry. It doesn’t come in useful very often (though I do make it a point to recite “Stopping by Woods on a Snowy Evening” every winter solstice), but it’s just good to know for its own sake.
I also know the entire radio phonetic alphabet (Alpha Bravo Charlie etc.), and just about know the Greek alphabet in order (I can recognize all the letters easily). And I’m up to about 40 on the periodic table, though some of them I really have to sit down and concentrate.
It’s also handy, in my line of work, to learn assorted physical constants (G, g, c, [del]h[/del], Avagadro’s number, etc.). And I know a large number of formulae, cast in quirky but useful forms: For instance, the tidal force exerted by an object is proportional to its angular diameter cubed times its density, or the surface orbital period around a spherical body depends only on its density, not its size.
The most important part of memorizing times tables as opposed to going to the calculator is that you find yourself using them in situations where it would never even occur to you to go for a calculator. Having a solid & competent grip on basic mathematics changes the way you approach problems.
Since I’ve moved to Germany from Canada, I find 24h time so much less ambiguous than 12h time, that I find it a pain to use when I’m back in Canada visiting…
Exciting, I know.
NB
How I’ve always remembered that way: Keep People Clean Or Forget Good Sex.
Kingdom, Phylum, Class, Order, Family, Genus, Species.
I’m surprised no one’s mentioned Morse code. I don’t have it memorized so I can’t say how handy it is, but I’d have thought it would be more useful than the radio alphabet, and several people have mentioned that. Anyone here happy that they’ve memorized Morse code?
Nonsense! Or should I say epic nonsense! I was stopped once and checked for drunk driving (I was falling asleep and swerving between lanes) and the policeman checking me asked me to recite the alphabet backwards.
Definitely useful for scrabble players.
You’ve inspired me, but just to be funny, I think I’ll memorize the French one - people will think I’m Célestin Oscar Oscar Louis.
For mental arithmetic, I’ve always found it easier to think of pi as 22/7. That’s what I was taught to use when doing mental arithmetic in front of the blackboard in grade school. In my grade school we also had to memorize multiplication tables up to 15 x 15.
It’s always good to memorize things related to topics you discuss often, e.g. topics related to your hobby or extracurricular activities. In my case memorizing the 30 articles of the Universal Declaration of Human Rights (the general idea, not the full text) has proven to be handy.
If you’re a physical scientist, learning common measurements in cgs units is extremely handy for scribble-on-napkin calculations, for example:
distance to the sun: 1.5 x 10^13 cm
surface tension of water: 50 dyne/cm
resistivity of copper: 2 x 10^-6 ohm cm
edit: The most useful?
Number of seconds in a year: 10^8 / pi. The pi usually cancels with something down the line.
The interesting thing about Morse code is that you can memorize the letters, but you have barely started to learn Morse code.
I remember as a teenager sitting at the dining room table with my dad and brother as we listened to tape after tape of code, carefully transcribing each letter into notebooks, building up our speed for our ham radio licenses. The process took some weeks.
Beginners (us) were supposed to be able to send and receive 5wpm, while a respectable rate was really around 15wpm. And it was always harder to receive than to send—you could key words much faster than your ear could interpret the code.
More advanced hams are able to hear entire words as units, recognizing them without the need to write down letter by letter.
Now to your question…
The only time this ever came in handy was when I was in the Navy, standing at the railing with some other guys, gazing at a distant ship that was communicating us with a flashing signal light. It was pretty cool to be the only guy in the group that knew exactly what the other ship was saying.