[keithlfrost]

No, I don't think so. Archimedes' principle tells us that the decrease in force required to support the object is equal to the weight of the displaced liquid. The force of gravity on the object itself is the same, regardless of which portion of the object is submerged.

[simon_acca]

Indeed, I also reached this conclusion upon thinking about it a bit more.

So a force sensor on the arm would only be good as a way of measuring what they are already measuring, that is, the volume of the displaced liquid.

[deckar01]

I'm not so sure. If the sensor was able to take a 2D measurement of the weight, the rotations could be used to calculate the 3rd dimension of density.

[derefr]

How about if you're using a compressible fluid?