Monday, September 06, 2021

[pbzphzds] density of water

many systems of measurement units attempt to link their units of mass and volume so that the density of water is a nice round number.  however, they seem to inevitably diverge away from it:

density of water is 1.0431756 ounce / fluid ounce .  if it were exactly 1.0, then a pint would be a pound the world around.  but it isn't, so it's not 8 pounds per gallon, but 8.3454045 lb/gal .

water density = 10.022413 lb/imperialgallon: originally 10.

the metric system nowadays defines meter and kilogram without reference to water, so the density of water has likely diverged from a nice round number 1 g/cc in metric as well.  how much does the maximum density of pure water (4 degrees C) differ from 1000 kg/m^3?  probably need to specify distribution of isotopes.

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