SEATTLE — There are few sensations quite as frustrating as knowing there is just a little bit of water stuck in your ear canal that refuses to come out. It’s happened to the best of us at one point or another after a dip in the pool or particularly long shower. Of course, one’s natural reaction may be to immediately start shaking their head violently in an attempt to force the water out, most of the time to middling results. Regardless of the strategy’s effectiveness, a new study warns this approach can actually lead to brain damage in small children.
Researchers from both Cornell University and Virginia Tech constructed various 3D printed ear canals of differing sizes, to represent age groups, and filled each with water. Then varying levels of acceleration were tested out on each model in order to gauge how much force of gravity is usually needed to eject water from the ear canal.
“Our research mainly focuses on the acceleration required to get the water out of the ear canal,” says study author Anuj Baskota, of Cornell University, in a media release. “The critical acceleration that we obtained experimentally on glass tubes and 3D printed ear canals was around the range of 10 times the force of gravity for infant ear sizes, which could cause damage to the brain.”
As we mature from childhood to adulthood, our ear canals grow larger in diameter. Thus, adults don’t require as much acceleration to rid themselves of water as children do. According to the study’s authors, the overall position and volume of the water present in the ear canal influences the amount of acceleration needed to remove it. Due to the small size of young children’s ear canals, denser accumulations of water can develop the in narrower passages.
“From our experiments and theoretical model, we figured out that surface tension of the fluid is one of the crucial factors promoting the water to get stuck in ear canals,” Baskota says.
It isn’t such a good idea to just leave the water alone, either. Water left stagnant in an ear canal can lead to infections such as swimmer’s ear. On that note, the research team have a suggestion on how to remove water from ears without head-banging.
“Presumably, putting a few drops of a liquid with lower surface tension than water, like alcohol or vinegar, in the ear would reduce the surface tension force allowing the water to flow out,” Baskota concludes.
The study was presented at the American Physical Society’s Division of Fluid Dynamics 72nd Annual Meeting.