A rotational deceleration experiment with egg yolk, using an egg scrambler and measuring the soft matter deformation, to find possible answers about concussions. (video link)

A growing number of professional football players have been diagnosed with a neurodegenerative disease called chronic traumatic encephalopathy (CTE), likely the result of suffering repeated concussions or similar repetitive brain trauma over the course of their careers. It’s also common in other high-contact sports like boxing, Muay Thai, kickboxing, and ice hockey. We might find clues about the underlying physics by studying the deformation of egg yolks, according to a new paper published in The Physics of Fluids. This in turn could one day lead to better prevention of such trauma.

Egg yolk submerged in liquid egg white encased in a hard shell is an example of what physicists call “soft matter in a liquid environment.” Other examples include the red blood cells that flow through our circulatory systems and our brains, surrounded by cerebrospinal fluid (CBR) inside a hard skull.  How much a type of soft matter deforms in response to external impacts is a key feature, according to Villanova University physicist Qianhong Wu and his co-authors on this latest study. They point to red blood cells as an example. It’s the ability of red blood cells to change shape under stress (“erythrocyte deformability“) that lets them squeeze through tiny capillaries, for instance, and also triggers the spleen to remove red blood cells whose size, shape, and overall deformability have been too greatly altered.