Physical Change:
* No new substances are formed. The change only affects the appearance or form of the substance, not its chemical composition.
* Usually reversible. You can often get the original substance back by reversing the change.
* No energy change is involved, or a small amount of energy is involved.
* Examples:
* Melting ice (solid water to liquid water)
* Cutting paper
* Dissolving sugar in water
* Boiling water
Chemical Change:
* New substances are formed. The chemical composition of the substance changes.
* Usually irreversible. You cannot get the original substances back by simple means.
* Significant energy change is involved. The reaction may release energy (exothermic) or absorb energy (endothermic).
* Examples:
* Burning wood (wood reacts with oxygen to form ash, carbon dioxide, and water)
* Rusting of iron (iron reacts with oxygen to form iron oxide)
* Cooking an egg (proteins in the egg change structure)
* Baking a cake (ingredients react to form a new substance)
Here's a simple way to remember:
* Physical change: Changes the look of something, not what it is.
* Chemical change: Changes what something is, not just how it looks.
Let me know if you'd like more examples or have any other questions!
