* Physical Properties: These are characteristics of a substance that can be observed or measured without changing the substance's chemical composition. Examples include color, density, melting point, and boiling point.

* Chemical Properties: These describe how a substance reacts with other substances or how it changes its chemical composition. Examples include flammability, reactivity with acids, and oxidation.

Why Boiling Point is Physical:

When a substance boils, it changes from a liquid to a gas. This change of state is a physical change. The molecules of the substance are still the same; they are simply arranged differently and moving more freely. No new substances are formed.

In contrast:

If you burn wood (a chemical change), you are altering the chemical composition of the wood. The wood reacts with oxygen to produce ash, carbon dioxide, and water. This is a chemical change because new substances are formed.