This article is a year and half old, but it’s still cool. From ZDNet:
Pouring beer in a mug involves multiply scattered acoustic waves. They are more complex to study [than singly-scattered waves like radar], but they can be used to look at various phenomena, such as predicting volcanic eruptions or understanding the movement of particles in fluids like beer. They also could be used to monitor the structural health of bridges and buildings or the stability of food products over time.
Tasty and helpful.