* Physical Change: A change in the form or appearance of a substance, but not its chemical composition.

* Chemical Change: A change that results in the formation of new substances with different chemical properties.

Boiling Water Explained:

* When water boils, it changes from a liquid state to a gaseous state (steam). The water molecules themselves remain the same (H₂O).

* The change is driven by an increase in temperature, providing enough energy for the water molecules to overcome the forces holding them together in the liquid state.

* You can reverse the change by cooling the steam, causing it to condense back into liquid water.

Key Takeaway: Boiling is a physical change because it alters the state of matter but does not change the chemical composition of the substance.