It’s all in the foam, researchers find
Vinicius Revecchi/Flickr (CC BY-NC-ND 2.0)
Carrying a cup of joe can prove dangerous: Just a small jostle can send hot liquid flying. A latte comes with considerably less risk. Thank the bubbles.
With a high-speed camera, the team recorded oscillations of a mixture of water, glycerol and dish soap inside a rectangular container after they jolted or rocked it. Pumping air into the liquid, the researchers created varied quantities of bubbles. Bubbles form in layers on top of a liquid, and five layers were enough to reduce sloshing as long as the bubbles touched the container’s sides. The researchers think that foam bubbles absorb the energy driving the liquid waves by creating friction at