Common Way to Remove Water from Ears Could Cause Brain Damage
When I was a kid, our family spent most summer weekends at the lake. Among the enduring memories is an image of my father standing on one leg, at least once every trip, pounding the side of his head to get water out of his ear. Modern science indicates this is not a technique he should’ve been teaching us kids.
New experiments with 3D-printed ear canals suggest the sudden acceleration of trying to shake water out could cause brain damage, with young children particularly at risk.
It takes a force of about 10 times gravity to get water out of the small ear canals of infants and small children, the scientists found. Other research, they say, finds an 8g to 10g impact when heading soccer balls can lead to lower academic performance in middle- and high-school students. (The threshold for concussions is higher.)
The sizes of ear canals vary by individual, so the researchers can’t say for sure what ages are most at risk from the ill-advised water-removal technique.
“Approximately, ages below 10 having smaller ear canals are in danger for sure,” study team member Sunghwan Jung, PhD, an associate professor Cornell, tells me. “But adults shouldn’t shake their heads either.”
Grownups, with their larger ear canals, need less force to get water out — about 5g, the experiments revealed. The findings were presented Saturday at the annual meeting of the American Physical Society’s Division of Fluid Dynamics.
Water in the ear is annoying at best. Left there, it can lead to infections in the outer ear canal — bacteria already in the ear canal love the water. Swimming in bacteria-laden water can increase the risk. The infection is commonly called swimmer’s ear (scientifically known as otitis externa).
Water gets stuck due to a simple scientific principle: “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,” says Jung’s colleague, Cornell undergraduate researcher Anuj Baskota.
Surface tension is the result of water molecules having a naturally stronger bond with each other than with air. So water molecules at the surface bond more strongly with other water molecules at the surface than they do with the air above. The surface of the water is resisting external forces, which can allow, for example, an insect to walk on water or even a paper clip to float on it.
There are other ways to get the water out your ear, from jiggling the earlobe to employing a yawning or chewing motion in the jaws. Eardrops can also help. But avoid my father’s other techniques, like cotton swabs and bobby pins. Sticking anything solid in your ear, including your finger, can worsen the problem.