Taking things a little further than in my last email ...
Using my conversion program and assuming 1 liter of water weighs 1
kilogram:
1 US fluid ounce of water will weight 1.043174 ounces.
1 UK fluid ounce of water will weigh 1.00224 ounces.
By "definition" (see below) a liter of water (at a certain temperature
and pressure) weighs 1 kilogram. At a higher temperature 1 UK fluid
ounce will weigh 1 ounce!
From
http://encyclopedia.thefreedictionary.com/litre: "A kilogram of pure water at a temperature of 4 °Celsius and standard
atmospheric pressure occupies approximately 1 litre of space.
"In the past, this was used to define the kilogram, but not anymore,
partially because the volume depends ever-so-slightly on the pressure,
and pressure units include mass as a factor, introducing a circular
dependency in the definition of the kilogram."