Final answer:
The question addresses a physical change where a solid dissolves into a liquid, altering its shape or size without changing its composition, as seen when salt dissolves in water. This points to concepts like changes of state and the physical process of separating mixtures in Chemistry.
Step-by-step explanation:
When substances are mixed and one dissolves, we observe a physical change wherein the object's shape or size is altered while retaining its composition and properties. This can occur in processes like changes of state, where a substance goes from solid to liquid or gas and vice versa, and the separation of a mixture. Both of these processes can significantly alter the form or appearance of matter.
Additionally, when substances are mixed and a new substance forms, such as a precipitate in a chemical reaction, this indicates a chemical change where one type of matter is transformed into another. A classic example is mixing table salt (sodium chloride) and water.