Oil, on the other hand, is nonpolar. The natural tendency of isolated systems is toward this state of greater disorder, which further drives the separation.
Understanding Polar and Nonpolar Molecule Interactions in Water and Oil
" Polar solvents are effective at dissolving other polar substances because their charges can interact favorably. The two substances seem to dance around each other forever, never truly combining into a single, uniform mixture.
Instead of mixing, the water molecules prefer to stay bonded to each other, effectively excluding the oil. Nonpolar substances, however, lack these charge interactions.
How Polar and Nonpolar Molecules Resist Mixing
Water molecules at the surface experience a net inward pull because they are attracted to other water molecules but not to the oil above them. This tension is the physical manifestation of the imbalance of intermolecular forces at the boundary between the two liquids.
More About Why do oil and water not mix
Looking at Why do oil and water not mix from another angle can help expand the discussion and give readers a second clear paragraph under the same section.
More perspective on Why do oil and water not mix can make the topic easier to follow by connecting earlier points with a few simple takeaways.
