> > If you place a small, live fish in a bucket of water, does this increase the weight over that of the bucket/water combination alone?
> >
> > My first response was to say "Yes" but then I thought about the displacement of the water and could not be so sure. What do you all think?
> >
> > Drac "Not to sharp on abstract problems" imaS

> If we assume that some water spills out of the bucket because it was full to the brim before adding the fish, then the fish will displace water equal to its volume from the bucket, and the change in weight will depend on the density of the fish compared to that of water. Since a fish has variable density which is usually close to equal that of water (as indicated by the fish's ability to stay in one place at various depths) I would assume that there would be essentially no change in the weight of the bucket. [...]
>
> Don

(-: This reasoning is otherwise impeccable in terms of known relations. The only quibble anyone could pick with the explanation is that a fish's body has greater density than water, so if you took a given volume of fish and an equal volume of water, the fish flesh weighs more than the water. The only reason that fish float in the first place is that they use a baglike sac filled with gas called a swim bladder, which they can regulate to give themselves "neutral buoyancy" when diving upwards or downwards.

Wolf "phish use physics" spirit