Is An oil and vinegar salad dressing a solution or mixture?

* Solutions are homogeneous mixtures where one substance (the solute) is dissolved evenly throughout another substance (the solvent). The components of a solution are mixed at a molecular level.

* Mixtures are combinations of two or more substances where each substance retains its own chemical identity. They can be heterogeneous (unevenly mixed) or homogeneous (evenly mixed).

Oil and vinegar don't dissolve into each other. They separate into layers, with the oil floating on top. Even when shaken, they eventually separate again, making it a heterogeneous mixture.