Thursday, January 10, 2013

Escape Velocity

by emilyl13, This post originally appeared at Radioactive Lab Rats.




Did anyone else watch Happy Feet and wonder why there were bubble trails behind the cute little dancing penguins when they were speeding around underwater? No? Maybe it’s just a marine biologist thing… I did, and after reading an article in the National Geographic I now know why!
Apparently, emperor penguins have managed to do something engineers have been trying to do with boats and torpedoes: use air as a lubricant to cut resistance to increase speed. Without the benefit of using air as a lubricant, the penguins can swim about four to nine feet per second. However, in short bursts they can double or even triple their speed to escape predators like leopard seals by releasing teeny tiny bubbles from their feathers which reduces the density and viscosity of the water around their bodies, letting them swim much faster than normal.
This is made possible by the penguin’s feathers, which like other bird’s they can fluff to insulate themselves with layers of air. Instead of having rows of feathers with bare skin between them like most birds, emperor penguins have a super dense uniform coat of feathers. Because the base of their feathers have little filaments which are less than half the width of a human hair, the air is trapped in a downy mesh that turns the air into tiny micro bubbles. These lubricate the penguin and allow it to reach maximum speed to avoid those pesky predators like leopard seals.
Engineers wouldn’t dream of attaching feathers to boats to make them go faster, however they are using the technology to create systems that lubricate hulls of containerships with bubbles and air-lubrication systems for supertankers. But they still haven’t quite caught up to the emperor penguins yet.

About this contributor: EmilyL13 is a high school student currently in Science World’s Future Science Leaders program, who is very interested in marine biology, and loves horseback riding and volleyball. She wants to be a research scientist, and one day she hopes to shed light on the many secrets the ocean holds.

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