Physical Changes:

* Change in appearance or form, but not in chemical composition. This means the molecules themselves remain the same.

* Usually reversible.

* No new substances are formed.

* Examples:

* Melting ice (water changes state from solid to liquid)

* Dissolving sugar in water (sugar molecules are dispersed but not changed)

* Cutting a piece of paper (changes size and shape, not the chemical makeup)

Chemical Changes:

* Changes the chemical composition of a substance, resulting in new substances with different properties.

* Usually irreversible.

* New substances are formed.

* Examples:

* Burning wood (wood reacts with oxygen to form ash, carbon dioxide, and other substances)

* Cooking an egg (protein molecules change structure and create new compounds)

* Rusting iron (iron reacts with oxygen to form iron oxide, a new substance)

Here's a simple way to remember:

* Physical changes are temporary and easily reversed.

* Chemical changes are permanent and often involve a release or absorption of energy.

Let me know if you'd like to see more examples or have any other questions!