You're absolutely right! Liquids that don't mix, also known as immiscible liquids, will form layers based on their densities. Here's why:

* Density: Density is a measure of how much mass is packed into a given volume. A denser liquid is heavier for the same amount of space.

* Gravity: Gravity pulls denser liquids down, causing them to settle at the bottom. Less dense liquids float on top.

Example: Oil and water are immiscible. Oil is less dense than water, so it will float on top of the water when they are mixed.

Here are some other examples of immiscible liquids that form layers:

* Vinegar and oil: Vinegar is denser than oil.

* Mercury and water: Mercury is much denser than water.

* Gasoline and water: Gasoline is less dense than water.

Let me know if you'd like more information about immiscible liquids or density!