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> Do you have problems with time too? How do you cope with that?

I have memorized how time and dates work, but I do not enjoy the system.

Time is my biggest sore point. For starters, doing any kind of arithmetic is an exercise in pain. For example when I rent a shared bike, the system tells me the start and end time to the second - for example, from 13:26:08 to 15:54:39. To calculate the duration, I have to combine the HMS into linear seconds, subtract the two linear timestamps, and then reformat it into HMS notation. Similarly, if I have to calculate ratios, percentages, histograms, etc., then HMS notation just gets in the way.

Have you ever tried writing logic to deal with HMS before? Here's an exercise for you (which I completed this month): Given a non-negative integer number of seconds, write out the number as a string formatted in DHMS format such that the leftmost unit cannot have leading zeros (so no 0m23s, no 09s) except for the special case of 0s, the string must be fully reduced (e.g. 83s -> 1m23s), and any non-leftmost unit must have full leading zeros (e.g. 1h2m3s -> 1h02m03s). The logic is pretty horrendous. The alternative, if everything was expressed in linear seconds, is completely trivial.

The second sore point about time notation is that although sub-second units (ms, μs, ns, etc.) are fine and dandy, any SI super-second unit (kilosecond, megasecond, etc.) is never used in practice and also has no alignment with days and years. This isn't merely a theoretical concern because that's how we get non-SI units like km/h, kW⋅h, and light-year. If ks was useful and popular, then km/ks just simplifies to m/s, whereas km/h = 3.6 m/s and kW⋅h = 3.6 MJ. Personally, I would've preferred the day to be subdivided into either a thousand or a million ticks, especially because I strongly prefer power-of-1000 prefixes (so milli- is good, centi- is bad).

As for dates, we can't get around the fact that there are roughly 365.25 days per tropical year. The Gregorian calendar is hacky because February is shorter than other months, a leap day is put at the end of February instead of the end of December, and the naming is shifted so that Sep (number 7) = 9th month, Oct (number 8) = 10th month, Nov (number 9) = 11th month, Dec (number 10) = 12th month. I think the least bad solution is the https://en.wikipedia.org/wiki/International_Fixed_Calendar .

>> Lots of useless names and numbers to memorize

You are correct to point out that time units have many weird names and conversion factors. Now on top of that, try learning all these names and conversion factors:

• Length: 1 mile = 1760 yards (let's skip furlongs and chains even though they are part of the derivation of the mile), 1 yard = 3 feet, 1 foot = 12 inches. Then there are industry-specific measures like mils in machining, points in typesetting, nautical miles.

• Volume: 1 US gallon = 4 quarts, 1 quart = 2 pints, 1 pint = 2 cups, 1 cup = 8 fluid ounces, 1 fluid ounce = 2 tablespoons, 1 tablespoon = 3 teaspoons. Also, 1 US gallon = 231 cubic inches exact, surprisingly. Throw in some more industry-specific units like cubic feet of water, cubic inches of engine displacement, acre-feet of rain, cubic miles of dirt mined, barrels of oil...

• Mass: 1 short ton = 20 hundredweights, 1 hundredweight = 100 pounds, 1 pound = 16 ounces, 1 ounce = 480 grains; also, 1 stone = 14 pounds (pervasive in UK but nonexistent in US).

• Power: horsepower, BTU/h, ton of cooling, possibly foot-pound-per-second.

The point is, all of the above names and numbers are completely arbitrary and you have to learn them all from scratch. If you aced the test on units of length, that has told you exactly nothing about the units of mass.

It should go without saying in the metric system, the following series mean exactly what you think they mean:

• Length: ... nanometre, micrometre, millimetre, metre, kilometre, megametre, gigametre, ... .

• Volume: ... nanolitre, microlitre, millilitre, litre, kilolitre, megalitre, gigalitre, ... .

• Mass: ... nanogram, microgram, milligram, gram, kilogram, megagram (metric ton / tonne), gigagram, ... .

• Power: ... nanowatt, microwatt, milliwatt, watt, kilowatt, megawatt, gigawatt, ... .

• Frequency: ... nanohertz, microhertz, millhertz, hertz, kilohertz, megahertz, gigahertz, ... .

If you know how many metres are in a kilometre, you know how many hertz are in a kilohertz - you didn't need to learn anything new. You just needed to think for two seconds upon the first time you heard that prefixed unit.

An LED bulb advertised as 2000 lumens (lm) can be easily rewritten as 2 kilolumens (klm) if you wanted to. A power bank marketed as 20000 mA⋅h can at least be simplified to 20 A⋅h (and 72 kilocoulombs if you get rid of the hour).



I don't know what do you do, but most people need to know how many yards (or inches, or feet, or chains, or whatever) in a mile as often as they need to know how many seconds, minutes, or hours in a quarter i.e. never. Yet it's the strongest point proponents of the metric system have, so makes me wonder why are they so agitated?

For the record, I am from a metric country and immigrated to the US as an adult. I still find American system to be more adjusted to human needs. E.g. temperature in F does not need decimals unlike temperature in C, tool sizing in inches is simpler (look at the sets of drill bits in different systems for example), tire pressure in psi (e.g. one of my bikes is 53 psi rear and 51 front, or 3.65 and 3.51 bars, you could say I could remember just the decimals, but another bike is 33 and 31, or 2.27 and 2.13 so no, it's 3 digits with bars vs 2 in psi), house dimensions are in even number of feet so much easier to find furniture, which is designed with this in mind, obviously. Miles are great to estimate time of travel by car, take 1 minute per mile of distance on a highway and 2 minutes in the city and you will be pretty close.

But, of course, the reason the American system is never going away is because it would be insanely expensive: you either will have to rewrite all building codes/standars/recipes with stupid conversions e.g 50.8x101.6 instead of 2x4 even though the lumber dimensions are not really 2 and 4 inches or scrape them and write the new ones using the more sensible metric dimensions but then you will need to scrape all the tooling you had and buy new, metric tools. All so you could say how many micrometers in a kilometer and feel smart?


> Miles are great to estimate time of travel by car, take 1 minute per mile of distance on a highway and 2 minutes in the city and you will be pretty close.

That might be true where you live, but it's hardly a universal constant. 1 minute per mile might be sort-of-universal for long distance Interstate driving, but then again, you can just as easily phrase that as ~1 hour per 100 km in metric.

I'm rather doubtful about your 2 minutes per mile (= 30 mph average speed) figure for "city" driving, though – how's that even possible when urban maximum speeds are usually in the 25 – 40 mph range, and that's not counting time lost for traffic lights and other intersections, general congestion and parking?

Checking a few destinations around where I live in Germany, non-Autobahn cross-country driving is closer to 2 minutes per mile rather than 1 minute per mile (and highly variable depending on your exact destination, so no point trying to estimate driving times to the nearest minute, anyway), and never mind actual urban driving.


>That might be true where you live, but it's hardly a universal constant.

I have not said it's a universal constant, it's true in the US, where we use miles. ~1 hour per 100km is not as easy.

I cannot say I care much if you are doubtful, especially if you live in Germany and not in the US, I doubt many people in the US will care about your doubts too.


Even in the US I'm doubtful about 2 minutes per mile being true for actual "city" driving if you live in a bigger conurbation.




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