When soup gets cold, it often tastes greasy. This 'greasy' taste seems to be associated with oil spreading out all over the surface of the soup, instead of staying in little globules. This is readily explained in terms of

Pascal's principle: If an external pressure is applied to a confined fluid, the pressure at every point within the fluid increases by that amount.
Archimedes' principle: The buoyant force on an object immersed in a fluid is equal to the weight of the fluid displaced by that object.

Bernoulli's principle: Where the velocity of fluid is high, the pressure is low; and where the velocity is low, the pressure is high.