Originally Posted by
UAL Traveler
Since a dry ounce (which is the same as a net-weight ounce) weights about 16% more than a liquid ounce, the 5oz net weight toothpaste would weigh more (5 x 1.16) than the the 3 fluid ounce tube of hair gel.
Actually, the weight of a dry ounce depends on the density of the material. 1 mL of water weighs approximately 1 g, and likewise 1 fl oz water weighs around 1 oz. But if something has a lower density than water, it can have more volume for the same mass of water (and vice-versa). @:-)