The metric system: Make your case for it and why we should switch to it. (As if we haven't already)

U.S. residents simply haven’t been indoctrinated into the SI units. Miles, pounds, ounces, yards, etc. are labeled everywhere so people get a feel for them from a very young age. They just don’t know the SI unit sizes- or so it would seem.

What may be necessary to instill some confidence in younger folks is to point out the units they already have a feel for but don’t know they do.
Grams- all U.S. currency notes have a mass of one gram each.
Liters- this one most people know. A liter is one quart plus an extra gulp. They don’t know one liter of water is one kilo. Therefore, those 500 ml bottles of water everyone totes around these days are a half kilo plus a few grams for the bottle, or just over one and one tenth of a pound.
A half kilo of ground beef would be the same as a pound plus a bite or two more.
Speedometers are informative- 50 mph is just about 80 kph which means one km is about 5/8 of a mile.
61 F = 16 C (approximately)

I found teaching the units this way made the students (9th graders) more comfortable when using the SI units.

Not if your thermostat only works in whole numbers. Setting a thermostat to Fahrenheit instead of Celsius allows more precision. And yes, I can tell the difference in how the house feels. The thermostat came with a factory default of Celsius which I used for a while, but switched to Fahrenheit because it allows for more precise heat.

I’m glad you have a workaround available, but it sounds like your system is the problem here not Celsius.

…Assuming that your system really is as accurate as it is telling you (home heating systems might not have a range of error as precise as a thermostat implies they do).

Except that it probably doesn’t, it just lets you pick a more precise set point. Your thermostat is a single point in your house where you measure the ambient temperature. The furnace turns on at the set point, runs for a minimum amount of time while the temperature goes above the set point. That range will not change regardless of the units on the thermostat. In the meantime, any other rooms in the house will be warmer or colder based on drafts, solar heating, etc.

Our system of measurement is totally unscientific. It makes no logical sense. What the hell is a “foot”, and why is it twelve inches? It only makes sense in our heads because we were familiarized with it from childhood, and we have a picture of a “foot” in our heads. How many “hands” high is a horse? It’s a joke for a first world country that is a leader in mathematics and technology. It’s also an indication that, in this country, the educated do not seem to be winning the battle against ignorance.

I don’t think there is an enormous benefit to changing ‘popular’ measurements with metric. Exchanging hectare for acre in real estate descriptions, km for mi in road signs and speedometers, and C for F in thermometers doesn’t really drive a personal benefit. All that happens is your intuitive understanding of the measurement applies to a different amount of whatever is being measured. “Hey, an acre is a nice chunk of land” vs “Hey, a half hectare is a nice chuck of land” doesn’t really do it for me.

From a scientific and engineering standpoint, metric is the way to go, 100%. Well… 99%, in building construction, we have a huge legacy issue with existing buildings based on a non-metric standard, and I have no idea how to transition over without a half century of pain and suffering for the industry, unless we’re just going to sell 1,219 x 2,438 plywood, and call it a day.

Well frankly it’s a flawed system, and I envy the places that are fully metric.
But the UK has chugged along with it for decades so places like the US can take it as proof that it doesn’t need to be all-or-nothing I guess (although they already have 2L bottles to suggest that).

One interesting phenomenon in the UK is how generational it has become. When helping out at a school I was surprised to learn that many teens only knew their height in centimeters, not in feet and inches (among the older generation, it’s the opposite). I guess people who have to routinely record such data get used to the fact that it’s one system for the young, and another for the old.

UK is mostly straightforward (well, OK, beer is sold in pints; but they’re proper pints, ie 20 ounces).

But I pay for timber (US: lumber) by the metre. And it’s all sold in 0.3 metre units! That’s to say, they’ll only sell you 2.4, 2.7. 3m, 3.3, 3.6 etc.
I.e. foot units.

Many Americans my age think mostly in pounds and ounces, but easily switch over to grams and kilos when recreational drugs are the topic.

In Norway and Sweden a “mil” is ten kilometers, because pre-metric (before 1875 in Norway) the Norwegian (land) mile was 11.295 km and the Swedish 10.689 km. (Both of them 18,000 ells).

“Mål” (literally “measure”) is still used to refer to land area. Just pre-metric it was 984,33 square meters, so it’s used as a synonym for “dekar” (1000 square meters).

Not just recreational drugs. Even large bottles of soft drinks!

I am old enough to remember when the soda distributors switched from glass bottles to plastic. But they didn’t change only the material - they also changed the size. The standard family size bottle went from 28 ounces in glass, to 2 liters in plastic. The bottle was bigger, of course, but not much heavier, and a lot safer.

Here’s what I’ve never been sure of, and I hope this is a good place to ask: Are there any stories about why they chose that particular moment in history to go metric?

A two-liter bottle holds more than 5% more than a 2-quart bottle. I know that (to the manufacturer) soda is almost as cheap as water, but it’s still not free. Why would they make such a large bottle? I can’t help but wonder if they anticipated a near-future switch to metric, so they figured to do it now while all the bottling machinery is being rebuilt.

Any thoughts?

As an additional side point, does anyone know when the liquor companies went metric?

The “4/5 quart” bottle was replaced by the 750 ml bottle. FYI, 0.8 quart is 757.1 ml, so (unlike the soda people) the new bottles are actually smaller, but only by 1%.

Alternatively, a 750 ml bottle is approximately 25 23/64 ounces.

For the bonus round, who can figure out in their head, whether 25 23/64 is smaller or larger than 25 369/1024 ?

Lots of people would have trouble figuring in their head whether 25 23/64 is larger or smaller than 25 3/8.

Who can say? But the world obviously needs 3-litre bottles of Frosty Jack

Exactly. Defining the metre as the length of the path travelled by light in a vacuum, in 1/299,792,458 of the time duration of 9,192 631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the fundamental unperturbed ground-state of the caesium-133 atom, is a far less arbitrary and more intuitive measure than an approximation of the length of the human foot.


Here is a copy of the original EEC harmonization directive from 1974:

Presumably many U.S.-only companies were forced to follow suit as well.

I have happily worked (and thought) for years in grams, milliliters and centimeters in medicine, then gone home and been contented with good ol’ American pounds, ounces and feet. Those industries that benefit from metric have pretty much all adopted it as far as I can tell. The general public doesn’t need to.

Also, I’ll give up Fahrenheit when you pry my dead cold (or steaming hot) hands from it.

Well, since customary units are defined in amounts of SI, SI is (by all your standards and definitions) less arbitary.

Presumably there is already a provision for inspectors to verify that the scales and weights used by your grocer, etc., are accurate. In a really for-real official switch it would not cost much more for those inspectors to fine any business not trading using approved units.

ETA remember this sort of nonsense?

That is not correct. The easy to remember conversion is 640 acres per square mile.

So you can divide a square mile into 8 by 80 acres. With 5280 feet per mile, that’s 660 by 66 feet per acre. Or, 220 by 22 yards. Or, 10 by 1 chains. Which is based on what a man and ox could plow in one day.