Physical Properties:
* What something IS: These are characteristics that describe a substance without changing its chemical composition. Think of them as the "identity card" of a substance.
* Examples: Color, odor, density, melting point, boiling point, hardness, state of matter (solid, liquid, gas), texture, luster.
* No new substances are formed: When you observe a physical property, you're not changing what the substance fundamentally is.
Physical Changes:
* What happens to something: These are changes in the form or appearance of a substance, but not its chemical composition. Think of them as changes in "how the substance looks or feels".
* Examples:
* Changes of state: Melting (solid to liquid), freezing (liquid to solid), boiling (liquid to gas), condensation (gas to liquid), sublimation (solid to gas), deposition (gas to solid).
* Changes in shape: Cutting, bending, crushing.
* Dissolving: Sugar dissolving in water.
* No new substances are formed: The substance remains the same chemically, even though it might look different.
Key Difference:
The key difference is that physical changes are reversible, while chemical changes are not (or at least not easily reversible).
* You can freeze water (physical change) and then melt it back into liquid water.
* You can cut paper (physical change), but you can't easily put the pieces back together to form the original sheet.
Examples to illustrate:
* Physical Property: Water is colorless and odorless.
* Physical Change: Water freezes into ice. (The water molecules are still H2O, just arranged differently.)
Let me know if you have any more questions!
