Solid

A solid object is in the states of matter characterized by resistance to deformation and changes of volume. At the microscopic scale, a solid has these properties :

The branch of physics that deals with solids is called solid-state physics, and is a type of condensed matter physics. Materials science is primarily concerned with properties of solids such as strength and phase transformations. It overlaps strongly with solid-state physics. Solid-state chemistry overlaps both of these fields, but is especially concerned with the synthesis of novel materials.

The lightest known solid is man-made and is called aerogel. The lightest aerogel produced has a density of 1.9 mg/cm3 or 1.9 kg/m3 (1/530 as dense as water).