Swimming often results in water getting stuck in our ear canals. The narrow space, combined with the waxy surface, is excellent at trapping small amounts of water. If left in place, that excess fluid distorts hearing, can cause pain, and may eventually lead to an ear infection. So most people’s common response is to tilt their head sideways and shake it or jump to knock the water out. This recent study looks at just how much acceleration is needed to dislodge that water.
The team built an artificial ear based on the shape of a human’s ear canal and observed how much acceleration was needed to knock the water out. The answer? Quite a bit. As seen above, nearly 8g of acceleration was enough to distort the interface of the water in the ear canal, but it didn’t move the water out.
At higher accelerations — above 20 times the acceleration due to gravity – the air-water interface distorts enough to get the water to flow. But accelerations that large are enough to potentially damage brain tissues.
The problem is worse for children and babies, whose tiny ear canals necessitate even larger accelerations. For them, shaking hard enough to remove water could cause real damage. Instead, a couple drops of vinegar or alcohol in the ear will lower the surface tension and make the fluid easier to remove. (Image credit: top – J. Flavia, others – S. Kim et al.; research credit: S. Kim et al.; submitted by Sunny J.)