Originally Posted by sneuman
...water weighs about 8 lbs/gallon...
Those would be "lite", not "real" gallons.
The Imperial gallon is now legally defined as 4.54609 litres, and was originally defined as the volume of 10 pounds of water
at 62 ̊F. An Imp. Gal is 277.42 cubic inches.
The U.S. gallon is legally defined as 231 cubic inches.
A US Gallon 231 cubic inches. A US Gal of water weighs about 8.33 pounds at 62 ̊F.
An Imperial Gallon of diesel weighs about 8.5191 pounds,
whereas a US Gallon of diesel weighs about 7.0936 Lbs.
Gasoline weighs about 7.504 Lbs/Imp Gal,
and about 6.2484 Lbs/US Gal.