Miscible Fluids - John Dunn, Consultant, Ambertec, P.E., P.C.

Life is just full of charming little mysteries and here's one of them.

When you take a cup of black coffee and add a little milk to it, the milk doesn't immediately disperse evenly throughout the cup. Instead, fluid layers form that appear to be quite stable. If left alone, the layers will remain as you see them on the left side of these two photos.

However, if you stir the contents of the cup, the layers mix and are gone. The contents merge into an apparently homogeneous mixture and do not separate out again.

Why is that so?

Comments

[Stewart Senator]

temperature difference