Physical changes are changes
affecting the form of a chemical substance, but not its chemical composition.
Solid is characterized by structural rigidity and resistance to changes of
shape or volume. The atoms in a solid are intact,compressed and are tightly bound to each other, either in a regular
geometric lattice.
Like a plastic ruler, when bent, it only changes its
form,not its chemical composition, solid does not change its chemical composition when bent, hammered or pressed, therefore plastic ruler when bent, or when being applied an extent force, only undergoes
physical change.