Chemical changes involve a substance undergoing a transformation that alters its chemical composition, resulting in the formation of new substances with different properties. Examples include iron rusting or wood burning, where the original substances cannot be recovered by simple physical means. In contrast, physical changes do not alter the chemical identity of a substance; they involve changes in state or form, such as water freezing into ice or sugar dissolving in tea. Physical changes are typically reversible, and the original substance can be recovered, unlike in chemical changes where the original substance is fundamentally changed.
