macliam

And in the UK we use Gallons (imperial) for consumption and Litres for purchase..... because you know it makes sense.....

Pulaski

You realize those are US fluid ounces, not imperial fluid ounces, right? .... US fluid ounces are about 4% larger than imperial fluid ounces.

SultanOfSwing

A great thing about the metric system is a litre is a litre wherever in the universe you might be filling up

caretaker

That much? I had no idea.
Still, 160 US ounces = 1.040842735185616 Imperial gallon according to this chart. https://www.convertunits.com/from/US...mperial+gallon
I only have my grade 12, but you'd think if the US ounce was 5% larger it would be somewhere around 1.20 gallons.
My apologies if I'm just missing sarcasm or a late April Fool's joke.
Oh, I did the math... (which I was not great at, ever) Ok, but to tell the truth, .04 Imperial gallons isn't an awful lot.
Surprisingly, I did quite well at measuring when building houses and doing renovations, and knew every 3 dart finish from 170 by heart.

Pulaski

I am not sure why you detoured through 160 floz (US) .... and I was "about" 1% adrift with what I remembered.

1 gal (US) = 3,785ml and there are 16 floz (US) in 1 gal (US), therefore 1 floz (US) = 236.6ml
1 gal (imp) = 4,546ml and there are 20 floz (imp) in 1 gal (imp), therefore 1 floz (imp) = 227.3ml

(236.6/227.3) = 1.04

caretaker

16oz and 20oz to the pint, respectively, but I get it. Our paint in Canada comes in 3.78 litre cans, which I always just assumed to be 128oz.
Our liquor in 750ml and 1.14 litre bottles, etc.

caretaker

Now I'm curious, why does the US have not only a unique measure for gallons, but ounces as well?
I found an answer from David Osofsky of the UK, who is smarter than the average bear.

The fluid ounces are different because the gallons are different. Rather than a gallon being based on a standard fluid ounce, the fluid ounce is based on the gallon of which it is a part.

Long ago there were many gallons. By the end of the 18th Century there were 3: 2 wet and 1 dry. The two wet gallons were the wine gallon and the ale gallon.

Earlier, the wine gallon had been defined as a cylinder 6 inches deep and 7 inches in diameter. Remember geometry? Volume of a cylinder is height times π(r)², so 230.90706blahblah cubic inches. For the reason of import duty standards, a law was passed in 1706 (Queen Anne) to standardise it as 231 cubic inches. After the US became independent and set its standards of weights and measures, it adopted the 1706 wine gallon of 231 cubic inches as the US gallon, the size it remains to this day.

The ale gallon was originally based on the ale quart as set by law under Henry VII as being 2 pounds of wheat using Troy weight. This worked out to be 70.5 cubic inches. Multiplied by 4, the ale gallon was 282 cubic inches. In 1824, influenced by the relationship of the kilogram and litre, the UK re-defined the ale gallon as 10 pounds of distilled water weighed by brass weights when the barometer is at 30 inches of mercury at 62° F (science, eh?) This changed it to 277.274 cubic inches. And they also chucked the other gallons, and this revised ale gallon became the Imperial gallon. This also worked out to 4.5460903 litres. The litre was changed (Napoleon rolled over) in 1964 so in Canada they made the Imperial gallon equal to 4.54609 litres. This was adopted in the UK in 1985.

This rambling story meant that the US gallon is the 1706 standard of the 231 cubic inch wine gallon and the Imperial gallon landing on the several times revised 277.419533 cubic inch ale gallon.

Gallons are divided into 4 quarts. Quarts are divided into 2 pints. And pints? The wine gallon pint is 16 fluid ounces and the ale gallon pint is 20 fluid ounces. This is why a pint of beer in the UK is 25% larger than a pint of beer in the US.

But as the gallons have different histories and standards, the ounces that compose them are slightly off from each other; the Imperial fluid ounce equating to 28.4130625 millilitres and the US fluid ounce equating to 29.5735295625 millilitres.

In the US, for nutritional labelling only, the fluid ounce is defined as 30 ml.

So, there you go. The US fluid ounce is about a millilitre larger than an Imperial fluid ounce because of the different gallons, and the history of those gallons.

Pulaski

That reminds me of how the pound sterling came to be divisible into 960 parts. On a handful of occasions over the past 18 years since I arrived in the US, someone has asked me about the pound sterling, and in response I explain that prior to 1970, when the pound was "decimalized" it had been divided into 240 pennies, and that the pound had comprised 20 shillings each of 12 pennies, and that after decimalization the UK had, for several year a 2½p coin, which was known as sixpence! ..... and then when they look suitably astounded, I add the division of pennies into ha'pennies, and farthings. ..... And then there are guineas!

macliam

It was all sensible until bloody Napoleon got his snout in......
How many chains in a hundredweight? How many groats in a furlong? What about the difference in terrestrial miles and nautical miles...... so much fun.
Then again, for non-US people the idea of "a cup" as a measurement? I use a cup for my tea that holds 1/2 litre, SWMBO has cups that hold 20ml.
How about time being "notional" and local until the coming of the railways?......
Odd thing is, we don't seem to be able to build as elegantly as the Georgians, or a decoratively as the Moors, despite all our "advances".

caretaker

No need to get racist. Having gone through metrification in Canada it was never much of a problem (a mechanic trying to get a wrench on my '68 Cortina down in the pit doing a wheel alignment really hurt his hand, cursed and threw his tools) but I cannot judge my fuel consumption with the litres per 100km light on the info console. I always have to think, "Oh, that's 33mpg, not bad!"

macliam

I just can't get my head around the "litres per 100Km" measure..... mainly because what I want to do is translate it to MPG and it isn't that straightforward!! I just don't have a reference for "good" in that measure, I know lower is good and highter is worse..... but where does it swap over?

The UK had a half-arsed metrication..... so both imperial and metric measures are still in daily use and nobody has been "forced" to convert. So things can be priced in Kilos but sold in Pounds, metric measures are changed to match imperial equivalents, etc., etc. You still order a pint of beer, but a litre of petrol..... and check your consumption in Miles per Gallon. You walk 2 miles to the stadium to run 100 metres. No wonder people get confused!!

Pulaski

It's not just in the UK - in France "une livre" is half a kilo, and I suspect that all countries still have echos of pre-metrication measures.

macliam

Yes, but it is a division of a kilo, whereas in the UK it isn't, it's still the same old imperial measure.

The weirdest one I ever found was in Portugal.... in the UK one thing that was immediately affected by metrification was copper pipe and fittings, so the "standards" became 15mm and 22mm rather than 1/2" and 3/4". Then my BiL was refitting his kitchen in Lisbon in the 90s and the pipe was sold in "thumbs" (polegadas).... the old equivalent of inches, either 1/2 polegada or 3/4 polegada.... neither decimal nor metric!!

caretaker

In Old Mexico a reliable standard of measure in the markets was the mano, or handful.

zzrmark

...And what about the groats, crowns, half crowns, florins and 'thrupney' bits?