usually, the solid phase. Water is a notable exception.
Solids are the densest state of matter for most substances. The variation of density for solids is typically very small.
A gaseous phase!
The gas phase
Solids
Solid, Liquid, Gas, or Plasma are all different types of states of matter.
Phase-space density is a measure of how densely particles are distributed in both physical space and momentum space. It provides information about the distribution of particles in a physical system by showing how closely packed they are in different regions of space and momentum. A higher phase-space density indicates a higher concentration of particles in a given volume of space and momentum, while a lower phase-space density indicates a lower concentration.
A physical property.
Examples: density, reactivity, phase.
Phase change. Liquid phase to gaseous phase (evaporation) Liquid phase to solid phase (solidification, freezing) Solid phase to gaseous phase (sublimation9 Etc...
Solid, Liquid, Gas, Plasma
Shape and volume
This sounds like you are describing a physical transformation. A physical transformation is when the chemical structure remains the same, but the phase is changed. Examples of physical transformations are phase transformations such as melting or boiling.