Just for the record, I wrote post 793 before doing any research. The methodology is pretty obvious, but just to be sure, I did a google search and found the reference in 794.
It remains true that measuring the amount of water displaced by a completely immersed object tells you its volume and tells you nothing about its weight.
You could, for example cast statues out of aluminum, tin and lead, from the same mold and immerse them in water. They would all displace the same amount of water, and you would learn nothing about their weight.
Wrong...as I pointed out this procedure tells us very much about a person’s mass, specifically how much mass they have in regards to muscle mass vs. fat mass/body fat.
It appears your research is incomplete or your logic is faulty, but that’s why they dunk people in the tank...to find out how fat they are, they could care less about their volume.
If it is so "obvious" to you, why did you suddenly change your tune after I posted Reply 787 this morning at 11:10:37 AM PST? A mere 7 hours before you started implying you already knew what you were denying in multiple posts. Did you suddenly realize your argument stating displacement only measures volume was suddenly untenable? And wrong?
What mechanism is used in a scale to determine weight/mass? Weighing something in a gravity field is merely either comparing its mass against a known reference mass as in a balance scale, or measuring the amount of deflection a—either coil or straight—the mass of the measured item causes in a spring in response to the force of gravity. Neither of these methods will work in freefall.
In freefall, to determine the mass of an object one must be able to apply a known force for a specific period of time and measure the resulting change in motion and then calculate the mass. OR... on can use the displacement method for objects less dense than water. One can also use any liquid that is denser than the object to be tested. Mercury is useful for very dense objects that would sink in water.