What is the purpose of the US customary system of measurement?

[tracer]

@bob_2

But, I note - in gallons and tenths of a gallon, not gallons and pints.

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Which, I should add, is one of the points I make in this video:

Tenths and Hundredths in U.S. Customary units

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[Lord_Feldon]

@MilTan

In fact, I’d guess that if the base-12 currency system had persisted to the present, there would be less incentive to change it: there is far less need to do unit conversions with credit/debit cards.

Even if it did persist, it’s possible that pence would have just gone away because of inflation. That would leave pounds and shillings, and that’s much more intuitive to decimalize informally.

[Kenm]

tracer has the answer why the clock and the calendar isn’t metric on one of his pages, here.

1370s – Pope Gregory XI’s monks become obsessed with devoting each possible instant of their lives to correctly worshipping God, which causes them to invent the second (1/60 of a minute, the way a minute was 1/60 of an hour). Those wacky timekeepers!

I can’t find Asimov’s three-decade-old-or-more paperback I have somewhere that has within it much the same explanation but expanded, and which involves the Babylonians (who else?) and their base-60 system which led to the 360-degree circle, which led to sun-dial markings and finally the mechanical clock.

[tracer]

@Kenm

tracer has the answer why the clock and the calendar isn’t metric on one of his pages, here.

1370s – Pope Gregory XI’s monks become obsessed with devoting each possible instant of their lives to correctly worshipping God, which causes them to invent the second (1/60 of a minute, the way a minute was 1/60 of an hour). Those wacky timekeepers!

Two things wrong with that:

1. That factoid was given to me by someone who’s been wrong many times before; and

2. Even if true, the minute and the hour pre-date 1370 by a looooooooong ways. As others (and your Asimov cite) have said, they were invented by the Babylonians.
   Also, what’s up with the 7-day week? I mean, seven?! Who the heck thought “heptadays” were a useful unit of time?!

[Kenm]

Yahweh. In Genesis.

[septimus]

@Colibri

I’ll admit, temperature is still the least instinctive one for me. I have a general sense of what 10s, 20s, and 30s mean in C but am less precise on intermediate numbers. However, that’s partly because in Panama I don’t see temperatures outside a narrow range.

Similarly for me, in Thailand, I’m not used to Celsius (though we might wear a sweater during our very brief “winter”).
This April was hot where I live with eight days at 40+. (April 2010 had a whopping nineteen days at 40+ :mad: )

[Colibri]

@septimus

Similarly for me, in Thailand, I’m not used to Celsius (though we might wear a sweater during our very brief “winter”).
This April was hot where I live with eight days at 40+. (April 2010 had a whopping nineteen days at 40+ :mad: )

We never get that hot in Panama. The hottest day of the year is April 8 with and average high of about 33 C.

But the coldest day of the year is January 20, with an average high of 32 C.

It’s really pretty much June year round.

[eschereal]

I was looking at another thread where they were throwing around this number “32” and it just sounded odd to me. They did not teach me that number (in an American HS), I find it much easier to remember 9.8. Not sure why that is.

[septimus]

@Colibri

We never get that hot in Panama. The hottest day of the year is April 8 with and average high of about 33 C.

But the coldest day of the year is January 20, with an average high of 32 C.

It’s really pretty much June year round.

Interesting. I wonder if this is true of all near-Equator countries, or whether your closeness to two oceans is key: when one is warming you the other cools, and vice versa.

Anyway, I guess my failure to intuit Celsius weather temperatures is partly that I never intuited Fahrenheit temperatures either. :smack:

[runningdude]

@TBG

Even people that use the metric system don’t use it right, so why should I bother to change?

I mean, how far is the earth from the sun in metric? If you said 149,600,000 km, congrats, you just used the metric system wrong. If you actually used it right, it would no longer be kilometers when the number is that big. For large distances you should go through megameters, gigameters, terameters, etc, but no, you just stick with kilometer making the whole thing pointless. Why even bother with kilometer, just stick with fugging meters and call it 149,600,000,000 m. Or better yet, just forget the whole thing.

Kilometers are the largest standardized unit in the SI (metric system). All “larger” units are theoretical based on the prefixed, but not used in practice.

[lance_strongarm]

@RedSwinglineOne

But that’s not the point. I don’t think anybody is saying that the American system is better. They are saying that converting to metric (from an individual’s standpoint) is more trouble than it is worth. Even with your examples I would say maybe once a year I need to do inch measurement calculations that I can’t do in my head. If we converted to metric I would be making similar conversions 20 times a day. Is 4 kilometers too far to walk? Is 1.8 meters tall? Is 90kg fat? It’s going to be 27degree C today, should I wear shorts or a jacket? I would be constantly converting metric to inch just to make the numbers mean something to me.

Even if I live another 50 years, converting to metric won’t simplify my life enough to make up for the hassle of learning metric.

Actually, I think it would very much simplify your life. You just don’t know it yet because you haven’t done it.

Lots of things are hard to learn, but worth learning. It’s the basic principle of education.

Metric is so much more rational than our system. You can not only easily calculate within measurements (1 km = 1000 m) but across them (1 liter = a cube 10 cm x 10 cm x 10 cm, etc.) The measurements are all linked to each other.

You would have to convert the numbers from your old system to make them mean something to you, sure, but not for 50 years. You’d get used to the new system. It’s like learning a new language - hard at first, and you translate from your old language, but soon you know the new one and think in it. And if it’s a much simpler language than your old one that the rest of the world is speaking, you’re better off.

[Colophon]

@kenobi_65

Perhaps; perhaps not. I imagine it depends on the person.

One of my best friends grew up in Ireland, using the metric system. She’s lived in the US for 20 years now (she’s 47), and, despite being a very bright person, she still stumbles over how to interpret Fahrenheit temperatures (i.e., is 80 comfortable or not? Do I want a sweater if it’s 55 degrees?)

Perhaps I’m odd, but growing up in the UK I find I know by heart the Fahrenheit conversion for any given Celsius temperature between 0 and 35, simply from having seen them side by side in weather forecasts my whole life. For example if I see that it’s going to be 22c today then I know without having to do any maths that it’s 72f. 7c? 45f. And so on.
Btw re fuel economy, an interesting fact is that the “metric” way of doing it (litres per 100 kilometres, the inverse of miles per gallon, so a smaller figure is better) yields units of square metres. So instead of saying that your car uses, say, 7 litres per 100km, you could say it uses 0.007m[sup]3[/sup] per 100,000m, or 0.07 square millimetres of fuel.

That seems silly, but if you imagine a tiny tube of fuel in front of your car being sucked up as you drive along, and realise that it would only need to be just over a quarter of a millimetre in diameter, it makes sense. And you realise just how little fuel a car needs.

[Chronos]

Incidentally, solar physicists do regularly use megameters, by that name, for describing features on the Sun.

[hibernicus]

@kenobi_65

Perhaps; perhaps not. I imagine it depends on the person.

One of my best friends grew up in Ireland, using the metric system. She’s lived in the US for 20 years now (she’s 47), and, despite being a very bright person, she still stumbles over how to interpret Fahrenheit temperatures (i.e., is 80 comfortable or not? Do I want a sweater if it’s 55 degrees?)

This is another example of where we should probably separate temperature from other measurements in this discussion.

As an Irish person of 47, your friend is almost certainly extremely conversant with inches and feet, pounds and pints, and so on*. These units probably come more naturally to her than do the metric equivalents. So it is probably only when it comes to temperature that she has difficulty. Celsius has been the temperature scale in everyday use for as long as I can remember, whereas metric units have been gradually introduced during my lifetime.

(* With the proviso that our pints are slightly different to yours, and we weigh ourselves in stones and pounds rather than in pounds.)

[hibernicus]

@Chronos

5: (bonus question) You go to Ireland and stay in a bed and breakfast. They serve a really good bread at breakfast, and you ask for the recipe. The recipe is measured in quarts, teaspoons, and tablespoons. What is that in quarts, teaspoons, and tablespoons? (this one actually happened to me)

Are you sure you are remembering this story correctly? I don’t think the unit “quart” is very well known in Ireland, and unlike in the US we specify quantity of flour in mass rather than volume units. Like this:

1lb plain white flour
1 teaspoon salt
1 teaspoon bicarbonate of soda
14fl oz buttermilk

Mmm. Now I’m hungry for soda bread.

[Mogle]

@runningdude

Similarly, the foot is a very convenient measure. A good number of people have shoes exactly, or nearly exactly, one foot in length. Need to estimate the length of a room? Walk toe-to-heal from wall to walk. Need to check if a car can fit though a gate? Walk toe-to-heal in front of the car. You almost always walk around with an accurate measuring device!

This just silly, unless you’ve actually measured your shoe first, “accurate” is not the word I would use to describe this method.

[hibernicus]

@Colophon

That seems silly, but if you imagine a tiny tube of fuel in front of your car being sucked up as you drive along, and realise that it would only need to be just over a quarter of a millimetre in diameter, it makes sense. And you realise just how little fuel a car needs.

From xkcd What-if:

But regardless of which units you use, there’s something strange going on here. Miles are units of length, and gallons are volume—which is length[sup]3[/sup]. So gallons/mile is length[sup]3[/sup]/length. That’s just length[sup]2[/sup].
Gas mileage is measured in square meters.
You can even plug it into Wolfram|Alpha, and it’ll tell you that 20 MPG is about 0.1 square millimeters (roughly the area of two pixels on a computer screen).
Unit cancellation is weird.
Ok, so what’s the physical interpretation of that number? Is there one?
It turns out there is! If you took all the gas you burned on a trip and stretched it out into a thin tube along your route, 0.1 square millimeters would be the cross-sectional area of that tube.

Someone once claimed to me that a car uses less fuel to drive a mile than the volume of ink that would be used by a Bic biro to draw a line of the same distance. Judging by the above calculation, that could be fairly close to the truth.

[R3d_Anonymous]

@Colibri

We never get that hot in Panama. The hottest day of the year is April 8 with and average high of about 33 C.

But the coldest day of the year is January 20, with an average high of 32 C.

It’s really pretty much June year round.

Dude, I almost dream to live in a climate like that. One of the things I really hate about living in CT besides high population density is how the temperature is not stable here at all unless it’s summer or winter (and I hate winter). In the spring, basically anything from a high of 5 degrees to 35 degrees Celsius is fair game here. I remember one time in spring it being like 27 degrees as a high temperature one day and the next only going up to 12! Living in a place where you have 4 seasons means a lot of adjusting and allergies.

Whenever I preach about summer being the greatest season of all, one of the things I mention is that I don’t like it to necessarily be very hot, but I just don’t want the winter to be cold. I just like it to be mildly warm (like 20-35 degrees C) throughout the year.

[johnpost]

@runningdude

Kilometers are the largest standardized unit in the SI (metric system). All “larger” units are theoretical based on the prefixed, but not used in practice.

meter(metre) can have any prefix allowed before it. kilo is the largest common prefix.

[AaronX]

Those used to the imperial system - can you convert, say, 2.567 km to miles, feet, inches? How many operations on a calculator does it take you?