This article investigates the relationship between particle size, true density, and the compressive strength of hollow glass microspheres (HGMs). Using the Bettersizer 2600 laser diffraction particle ...

It can be impossible to identify full virus particles from empty ones based on size or shape alone. The particle's buoyant density can help you to distinguish between otherwise identical populations.

Even with some understanding of infinite density, it seems impossible for the enormous mass of the universe to arise from a subatomic particle. How is this possible? K. M. Johannsen, Storm Lake, Iowa ...