A physical change is a transformation of a substance from one physical state or form to another without altering its chemical composition. The substance involved remains chemically the same, so the change can often be reversed by physical means. Melting ice into liquid water is a physical change, in contrast to a chemical change, in which new substances form.

物理变化是物质在不改变其化学组成的情况下由一种物理状态或形式转变为另一种的转变。所涉物质在化学上保持不变,因此这种变化常可通过物理方法逆转。冰融化成液态水是物理变化;与之相对,化学变化中则会生成新物质。