Final answer:
Matter experiences physical changes, which do not alter its chemical composition, and chemical changes, which result in new substances with distinct molecular structures. Evidence such as color or temperature changes can indicate a chemical change.
Step-by-step explanation:
Physical changes involve the conversion of a substance from one state of matter to another, without changing its chemical composition. Examples of physical changes include melting ice, boiling water, and cutting paper. In contrast, chemical changes result in the formation of new substances with different chemical compositions. Examples of chemical changes include burning wood, rusting iron, and digesting food.
One key difference between physical and chemical changes is that physical changes can often be reversed, while chemical changes are usually irreversible. Physical changes only affect the physical properties of matter, such as its shape, size, or state, while chemical changes involve the rearrangement of atoms and the creation of new substances.