What happens to the brain when it receives a sudden shock? When I experiment with egg yolk, it looks like this

Boxing, soccer, and American football players, who often experience physical shock to their heads, often suffer from '

chronic traumatic encephalopathy, ' the so-called punched ranker . A paper was published that used egg yolks to verify how the brain inside the skull was shaken when it was actually physically impacted from the outside.

How to deform an egg yolk? On the study of soft matter deformation in a liquid environment: Physics of Fluids: Vol 33, No 1

Eggs reveal what may happen to brain on impact | EurekAlert! Science News

What happens to the brain on sudden impact? Egg yolks could hold the answer | Ars Technica
The skull is filled with cerebrospinal fluid , and the brain is floating in it. Previous studies have shown that when a soft substance deforms in a liquid, the flow of the liquid changes rapidly. A research team led by Qianhong Wu of Villanova University in the United States newly asked 'whether there is a possibility of damaging the brain without breaking the skull' using egg yolk floating in the egg white in a hard shell. I investigated.

Previous studies have shown that when a soft substance deforms in a liquid, the flow of the liquid changes rapidly. The research team investigated 'whether it is possible to damage the brain without breaking the skull' using the yolk that floats in the egg white in a hard shell.

The experimental equipment prepared by the research team is as follows. The device A contains egg white and yolk in the container of (a), and the weight of (c) drops from above to give an impact. The device B uses the motor (g) to rotate the container containing the egg white and yolk.

As a result of the experiment, in the device A that gives a vertical impact, the yolk hardly deformed and maintained an oval shape as shown in the image below.

However, in device B, which gives a rotational impact, the yolk quickly deformed significantly, extending once horizontally and then increasing its radius in the vertical direction. You can see how it transforms by looking at the picture below.

In addition, you can see the movie that shows how the yolk is deformed in the device of B below.

Rotational deceleration experiment with egg yolk --YouTube

To confirm that this deformation is not unique to egg yolk, the researchers conducted the same experiment by submerging calcium alginate capsules used in artificial salmon roe in a calcium lactate solution, and obtained the same results as egg yolk. It was said that. From this, the research team argued that 'the main mechanism leading to the deformation of soft substances in a liquid environment is the result of mechanical forces rather than biological reactions.' He further claims that 'centrifugal force due to rotation, especially slow rotation, has a harmful impact on the brain.'

'For example, when a boxer hits the chin sharply, the chin is the farthest point from the neck, so the speed at which the head rotates can be the greatest,' Wu said. , It is pointed out that the impact of swinging the head from side to side with the punch has a greater effect on the brain than the linear impact of the punch. 'This study can be applied not only to the brain, but also to the study of red blood cells in the blood,' Wu commented.

in Science,   Video, Posted by log1i_yk