* No new substance is formed: When salt (NaCl) dissolves in water, the sodium (Na+) and chloride (Cl-) ions separate and become surrounded by water molecules. The salt itself doesn't change its chemical composition. It's still NaCl.

* The change is reversible: You can easily recover the salt by evaporating the water. The salt crystals will reappear.

* The change doesn't involve breaking or forming new chemical bonds: The ionic bonds in the salt crystal are merely weakened by the water molecules, allowing the ions to separate and disperse.

In contrast, a chemical change would involve the formation of new substances with different chemical compositions. For example, burning wood is a chemical change because it produces ash, carbon dioxide, and other substances that are chemically different from the original wood.