Water changes from liquid to gas through a physical change called evaporation. Here's why:

* Physical Changes: These changes alter the form or appearance of a substance, but not its chemical composition.

* Chemical Changes: These changes involve the formation of new substances with different chemical properties.

Evaporation is a physical change where liquid water absorbs energy (usually heat) and changes into water vapor (gaseous water). The chemical composition of the water remains the same (H₂O).