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The US doesn't use the Imperial system, it uses US customary units. They're similar but very different. An Imperial pint is 568 ml; a US pint is 473. An Impe

The US doesn't use the Imperial system, it uses US customary units. They're similar but very different. An Imperial pint is 568 ml; a US pint is 473. An Imperial hundredweight is 112 lbs. A US hundredweight is 100.

hilbert42 1y ago
They're similar but very different. Right. …And that's even worse—the US wasn't even satisfied with the well-established Imperial system and had to mess it up. Everyone who takes an interest in measurement matters knows the story of the various aircraft that have run out of fuel because the US 'shortchanged' the gallon. It'd be funny if it wasn't so serious, the last major incident was an Air Canada flight in the 80s. The rest of the world shakes its head in disbelief.
- maxerickson 1y ago
  The Gimli Glider? Wrong size gallons is a terrible analysis of that incident. The fueler reported that the density of jet fuel at the time was 1.77, which was in lb/L, since other Air Canada aircraft used lb. Pearson and Quintal both used the density of jet fuel in lb/L without converting to kg/L In fact, Air Canada was in the process of standardizing their fleet on metric, but failed to carefully train their personnel and failed to establish procedures for accurately transmitting measurements.
- saalweachter 1y ago
  Actually, the Imperial system messed itself up, post-1776. The US did screw up a bit by standardizing on the wine gallon (231 cubic inches) instead of 222 cubic inches. This leads to a fluid ounce that is about 4% larger than an Imperial fluid ounce, and breaks the "a pint's a pound the whole world round" relationship (an Imperial fluid ounce of water weighs an ounce, and a pint of water being 16 fluid ounces is also a pound, which is 16 ounces of weight); in the US, a gallon of water now weighs "a little more" than 8 pounds. Of course, in the UK, an Imperial gallon of water now weighs exactly 10 pounds. This is because in the 1820s -- which you will note is half a century after the US and UK parted ways -- the UK decided to add more factors of 10 and 7 into their units, and redefined the pint to be 20 fluid ounces instead of 16, and a gallon became 160 instead of 128. The US and UK systems of measure diverged after 1776, and I'd argue the UK system changed more during standardization and re-standardization from the semi-formal system they shared before.

hilbert42 1y ago

They're similar but very different. Right. …And that's even worse—the US wasn't even satisfied with the well-established Imperial system and had to mess it up. Everyone who takes an interest in measurement matters knows the story of the various aircraft that have run out of fuel because the US 'shortchanged' the gallon. It'd be funny if it wasn't so serious, the last major incident was an Air Canada flight in the 80s. The rest of the world shakes its head in disbelief.

maxerickson 1y ago
The Gimli Glider? Wrong size gallons is a terrible analysis of that incident. The fueler reported that the density of jet fuel at the time was 1.77, which was in lb/L, since other Air Canada aircraft used lb. Pearson and Quintal both used the density of jet fuel in lb/L without converting to kg/L In fact, Air Canada was in the process of standardizing their fleet on metric, but failed to carefully train their personnel and failed to establish procedures for accurately transmitting measurements.
saalweachter 1y ago
Actually, the Imperial system messed itself up, post-1776. The US did screw up a bit by standardizing on the wine gallon (231 cubic inches) instead of 222 cubic inches. This leads to a fluid ounce that is about 4% larger than an Imperial fluid ounce, and breaks the "a pint's a pound the whole world round" relationship (an Imperial fluid ounce of water weighs an ounce, and a pint of water being 16 fluid ounces is also a pound, which is 16 ounces of weight); in the US, a gallon of water now weighs "a little more" than 8 pounds. Of course, in the UK, an Imperial gallon of water now weighs exactly 10 pounds. This is because in the 1820s -- which you will note is half a century after the US and UK parted ways -- the UK decided to add more factors of 10 and 7 into their units, and redefined the pint to be 20 fluid ounces instead of 16, and a gallon became 160 instead of 128. The US and UK systems of measure diverged after 1776, and I'd argue the UK system changed more during standardization and re-standardization from the semi-formal system they shared before.