On the one hand, it seems like there's a higher density of 'stuff' in a nucleus, so it should be more dense. On the other hand, if it was more dense, I'd imagine that nuclei would 'settle' to the bottom of a cell, which would be rather surprising.
Update: http://www.eng.umd.edu/~nsw/ench485/lab10.htm reports nucleic density of 1.4 g/cm3.
https://books.google.com/books?id=t4ZQRWvr510C&pg=PA85&lpg=PA85&dq=cytoplasm%20density%20g%2Fcm3&source=bl&ots=rEkcu0HzZE&sig=Bs4MVad_pbS7vWY2pRv6ALWf-bc&hl=en&sa=X&ved=0ahUKEwj2rLXVnLbJAhVSlogKHUjAAS8Q6AEIMTAD#v=onepage&q=cytoplasm%20density%20g%2Fcm3&f=false reports a density of 1.03 - 1.1 g/cm3 for cytoplasm, so less dense.
do nuclei sink then? or is ICF too viscous / there too much disturbance through movement for nucleus to sink?