The positive end of a water molecule is attracted to the negative ions or regions of a salt crystal, pulling it apart and into solution. Oil, on the other hand, is nonpolar.
How Surface Tension Keeps Oil and Water in Separate Layers
Consequently, the system minimizes its energy by keeping the substances segregated. Interfacial Tension: The Skin on the Surface If you have ever seen a droplet of oil sit perfectly on a puddle of water, you have witnessed interfacial tension in action.
This tension is the physical manifestation of the imbalance of intermolecular forces at the boundary between the two liquids. Its molecules are essentially symmetrical bundles of electrons that share their charge evenly, creating no significant positive or negative regions.
How Surface Tension Keeps Oil and Water in Separate Layers
The two substances seem to dance around each other forever, never truly combining into a single, uniform mixture. Nonpolar substances, however, lack these charge interactions.
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.
