* Density is mass per unit volume. So, any change in either mass or volume will affect density.
Here are some examples:
* Compression: Squeezing a substance into a smaller volume increases its density.
* Expansion: Heating a substance (like a gas) causes it to expand, decreasing its density.
* Phase Changes:
* Solid to Liquid: Water expands when it freezes, making ice less dense than liquid water.
* Liquid to Gas: A gas takes up much more space than the same amount of liquid, so its density is much lower.
Important Note: While physical changes affect density, chemical changes often result in a *new substance* with a different density.
Let me know if you'd like more specific examples or have further questions!
