Hearing

Just when you thought you'd heard everything, [scientists:researchers] have found that the reason you can hear everything - including things that are very quiet - is because your ears have tiny tubelike motors that mechanically amplify sounds.You've probably heard that it's the hair cells in your ears that allow you to hear. These cells sport tufts of spiky hairs that are like little molecular Mohawks. When sound waves enter the ear these hairs vibrate, and that motion then gets translated into an [electrical:word] message that tells your brain that there's something worth listening to. But the [movement:transmission] of those hairs is not passive, like tall grass swaying in the breeze. The electrical signals they produce feed back on the system, causing the hairs to tilt even more. It's that [so-called:thought] "flexo-electric effect" that boosts the audio signal and amplifies the sound, findings [published:issued] in the April 22nd issue of the journal Public Library of Science ONE.The scientists behind the study also note that the length of the hairs in different species explains why animals like bats can detect such high frequency [sounds:waves] . It doesn't, however, explain why your kids can hear their cell phones vibrate two rooms away, yet they never seem to hear a word you say.