* Physical Changes: These changes alter the appearance or form of a substance but don't change its chemical composition. Examples include melting ice (solid to liquid), boiling water (liquid to gas), or crushing a rock.

* Chemical Changes: These changes involve the formation of new substances with different chemical compositions. Examples include burning wood, rusting iron, or baking a cake.

* Temperature: Temperature is a measure of the average kinetic energy of particles in a substance. While heat can increase temperature, it's not the change itself.

How heat affects changes of state:

* Breaking bonds: When you add heat to a substance, the particles gain energy and vibrate faster. This increased energy can overcome the forces holding the particles together in a solid (like ice), causing them to move more freely and transition into a liquid (water).

* Creating bonds: When you remove heat from a substance, the particles lose energy and slow down. This allows the attractive forces between particles to become stronger, causing a gas to condense into a liquid or a liquid to freeze into a solid.

In summary: Heat can cause changes in the arrangement of particles within a substance, leading to transitions between solid, liquid, and gaseous states. These are physical changes, not chemical changes.