The research on why foamy liquid (such as beer or latte) is less likely to slosh out of a cup than non-foamy liquid (such as black coffee), has now been formally published. The study is:
The slosh team presented their work in public a few months ago, at the Annual Meeting of the APS Division of Fluid Dynamics.
A few years, earlier, that annual meeting went gaga, to a very limited degree, for a research presentation about why a cup of coffee is so very easy to spill (or, looked at from the other direction, why it’s so difficult to NOT spill a cup of coffee). That coffee-spill research was eventually honored with the 2012 Ig Nobel Prize for fluid dynamics. Here’s the Ig Nobel citation for that prize:
Rouslan Krechetnikov and Hans Mayer for studying the dynamics of liquid-sloshing, to learn what happens when a person walks while carrying a cup of coffee.
REFERENCE: “Walking With Coffee: Why Does It Spill?” Hans C. Mayer and Rouslan Krechetnikov, Physical Review E, vol. 85, 2012.
In 2013, that coffee-spill research was the subject of a dramatic demonstration by Karolinska neuroscientist Gustav Nilsonne, at the Karolinska Institute in Stockholm. Here is an action photo from that demonstration:
A month from now, Gustav Nilsonne will perhaps repeat that demonstration, with both coffee and beer, when the 2015 Ig Nobel Eurotour descends on the Karolinka Institute, on Monday afternoon, March 30. (There will be a second show in Stockholm, at Boulevardteatern, in the evening.)
(Thanks to investigator Mason Porter for bringing this to our attention.)