For most traditional measures there was no such thing as an official conversion factor between miles, chains, rods, furlongs, feet, inches, yards, or whatever, because each traditional measure was used in different contexts, and you’d almost never convert between systems. Along comes the 19th century and various national standards start to emerge, and you get official conversions between incompatible measures, and now for the first time we know how many teaspoons are in a hogshead. But of course that introduces additional problems because the standards set by one body don’t match the standards set by another body, and so we have multiple definitions of the ton, we have the mile and the nautical mile, and crazy shit like that.
Hey, metric keeps one traditional unit, the second, which is 1/60th of 1/60th of 1/24th of one day. Nowadays the metric second isn’t defined by the day but by the amount of time it takes for a certain number of vibrations of cesium at such and such conditions. If we were starting over from scratch we could have picked round numbers for this rather than some arbitrary number, but it doesn’t really matter much because only people building atomic clocks have to know the number, and if they don’t have that number written down then maybe they should change careers.
Oh, yes you did! There’s these things called “borders”, and every time you crossed one your units of measure changed, you see, but often while keeping the same exact name! And border taxes were based on the local unit, of course. And you had to pay them in every border, and some of the realms which had their own units were smaller than a county - either UK or US.
The answer to the original question of how people were able to convert with relative ease from the British system to the international standard system is that British law defined fixed conversion factors.
And you don’t even to memorize the formula. I derive it when needed by converting 100C to 212 F and back. The 32 falls out from freezing point. Trivial.
You need to check your assumptions. Yes, there is a link between our ten fingers and base ten, but there are a lot of languages out there not using base ten, and reminders of the non-dominance of base ten living on in indo-european languages as well.
Not just in words like score, dozen and gross, which can sort of be handwaved away as affectations, but in the fact that our base ten counting numbers start with twelve different numbers before going into what is clearly base ten. The etymology is apparently base ten, but different from the rest of the “tens”.
Danish and French both have clear vigesimal counting numbers, and prior to the 15th century “hundred” in Germanic languages was what came to be known as a long hundred, namely ten dozen.
The “weird” measurement systems arose in that world of mixed base counting and adding/subtracting done mostly in your head, not in the modern world where everyone learns multiplication and division with arabic numerals in a solid positional base ten system.
To add to this, simply counting touching the joints fingers with the thumb works for base 12, and just counting without the thumb leads to base 8. Or you can just ignore the innermost joint and count like you do with base 12. Consider with base 12, if you fold two of your fingers you can just count the remaining joints and get half.
The Sumerians and the Babylonians were base 60 thus our time, angles etc…
Base 10 just happened by chance, probably because of the Egyptians,
Funny enough, 1,2,6,7,8 and 9 loaves of bread are divided among 10 men and how decimal base was a challenge for them too
For what it’s worth, I grew up at the very edge of the Appalachian Plateau where it comes closest to meeting the Great Lakes – we were a couple hundred feet above them, and we never had to factor the differing boiling point of water into our cooking.
This of course includes the huge majority of the world’s population who also live near sea level.
I’m not especially fond of the metric system, although I only especially like the American units when it comes to inches and pounds, but I still don’t think there is any support for the view that elevation affects whatever elegance the 100C = boiling point mnemonic has.
I don’t know why it should matter, but in 1994, the median [del]zombie[/del] person [del]un-died[/del] lived at an elevation of 194 ft above sea level [cite]. That makes the boiling point of water something like 99.3 degrees Celcius for the median [del]zombie[/del] person.
I taught high school science in the U.S. for years. The only reason people are resistant to the SI units is because they have no clue of their sizes, or don’t realize they do.
Anyway, people here know grams and kilos better than they think they do. All U.S. currency notes have a mass of 1 gram. Water is 1 kg per liter for all practical purposes, so those 500 mL bottles of water people waste money on are 1/2 kilos, minus the bottle. Half a kilo is close enough to a pound for most cooking purposes.
Over the last 20 years I taught, we never did metric to traditional unit conversions. There is simply no need to do that. Want to measure centimeters? Use that side of the ruler! Kids never had any problems using and reading meter sticks, triple beam balances, and graduated glassware.
…and 60 miles per hour is about 100 kilometers per hour – so if you’re driving somewhere 120 miles away (the US is a big place), it’ll take you 120 minutes to get there. In Canada, the sign would say your destination is 200 km distant, and you could easily figure that it’s about two hours travel time. I’m just saying that metric highway distances aren’t that hard to figure out.
Yes, divide by a 100 because you are going 100 k/hr as you said.
For a slightly more complex example the sign says you are 70 k from your destination.
70 / 100 = .7 hours
.7 x 60 = 42 minutes.
Or 70 x 6 / 10 = 42 minutes.
If we really wanted a computer-friendly system, we would change from decimal to hexadecimal and create new standards based on that. A nice bonus is that to all intents and purposes, we ought to omit the quadrennial leap year almost precisely every 128 years, which is 80 in hex.
I have noticed that in many places in Europe pounds (livres, pfunde) are used to mean 500g. Reasonable. A friend of mine spent a couple years in Norway. When he wanted a length of 2 x 4, he went to a lumber yard and asked for a length of wood 5 x 10 cm and heard the clerk call to back to the cutting room for a 2 x 4. (I know these measures are not exact. Not the point.)
But the argument for metric standardization is basically that before metrization, every country had its own standards. At the peak of a small mountain outside of Zurich, there is a display that says that this point (these numbers are actually made up, but the idea is correct) is 810 meters above sea level, or 2657 English feet, or 2743 French feet, or 2581 German feet, or 2613 Italian feet. It is even worse than that. In England, every profession had its own units. There were the dairyman’s gallon, the brewers gallon, the oilmonger’s gallon, etc. and the same for weights.
The way I convert C to F (and vice versa) is to add 40 multiply by 5/9 (or 9/5) and subtract 40. But the reason that temperature conversion is harder than the others is that there is a different zero point. I once lived for a year in an apartment in Zurich that had a thermometer hanging outside a window that had both celsius and reaumur scales. Since R is exactly 4/5 of C, I soon discovered that if I added the two readings and added 32 I got F.
