Why coffee is easier to spill than beer

A team of scientists from Princeton University conducted a serious study and found out why beer is harder to shed from a glass when churning than coffee. The results of scientific work are presented on November 24 at the conference of the American Scientific Society, in the section on fluid dynamics .


See the full version of the video with the description of the experiment, mp4

The answer is in the number of bubbles on the surface, that is, in the thickness of the foam.

There is such a scientific term - sloshing . In fluid dynamics, it means moving the fluid inside another object (which is usually in motion).
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So, a layer of foam with a thickness of only 0.3 cm is enough to significantly suppress bleeding, and a layer of 3 cm suppresses bleeding almost completely.

The study of Princeton physicists is of tremendous practical value for the safe transportation (and transportation) of fluids inside other objects. It is enough to cover it with a layer of foam - and the pressure on the walls of the container will decrease, and the liquid will not splash out when rocking.

Well, coffee lovers now know why coffee with foam splashes worse than coffee without foam. It just squishes less.

via New Scientist