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- ''For other meanings of "ultrasound" or "ultrasonic", see ultrasound (disambiguation).
Ultrasound is sound with a frequency greater than the upper limit of human hearing, this limit being approximately 20 kilohertz (20,000 hertz).
Ability to hear ultrasound
Some animals, such as dogs, dolphins, bats, and mice have an upper limit that is greater than that of the human ear and thus can hear ultrasound. Children can hear some high-pitched sounds that older adults cannot hear, as in humans the upper limit pitch of hearing gets lower with age. This frequency limit is caused by the middle ear that acts as a low-pass filter. If ultrasound is fed directly into the skull bone and reaches the cochlea without passing through the middle ear, much higher frequencies (up to about 200 kHz) can be heard. This effect (sometimes called ultrasonic hearing) was first discovered by divers exposed to a high-frequency (ca. 50 kHz) sonar signal.Medical sonography
More on [ Ultrasound ]
U - Twitter Search
Are U a rude clown who ran out of clever jokes with no laughing/paying audience?Fix it - run 4 office, cheat & win!
barnablues (jrvsanmartin) Wed, 16 Dec 2009 20:02:20 -0000
Are U a rude clown who ran out of clever jokes with no laughing/paying audience?Fix it - run 4 office, cheat & win!
I got 2 more bitches arguing on my timeline rt now, how the fuck u gon type out an argument?? LOL, I see chicks gettin no better in #2010
cnoaht (Christopher Edward) Wed, 16 Dec 2009 20:02:19 -0000
I got 2 more bitches arguing on my timeline rt now, how the fuck u gon type out an argument?? LOL, I see chicks gettin no better in #2010
@Robsessed83 ya done good. I'm gonna go on vacay for a while. U keep that cape and keep saving those lost souls out there.
tinkrbe1l3 (Tinker Bell) Wed, 16 Dec 2009 20:02:19 -0000
@Robsessed83 ya done good. I'm gonna go on vacay for a while. U keep that cape and keep saving those lost souls out there.
@Anthoonys haha u dumbbb
MervDiggity_011 (Merv Lindsay) Wed, 16 Dec 2009 20:02:19 -0000
@Anthoonys haha u dumbbb
@WestlifeTwinkle why u hate lady gaga?
Neoark25 (Ahmed Alhussaini) Wed, 16 Dec 2009 20:02:19 -0000
@WestlifeTwinkle why u hate lady gaga?
@jus_q heeeeeeeey Sister Q!!!!! What are u doing?!?!?!
1stGlamazon (Yazmine) Wed, 16 Dec 2009 20:02:19 -0000
@jus_q heeeeeeeey Sister Q!!!!! What are u doing?!?!?!
Subscribe to U RSS feed 
Are U a rude clown who ran out of clever jokes with no laughing/paying audience?Fix it - run 4 office, cheat & win!
barnablues (jrvsanmartin) Wed, 16 Dec 2009 20:02:20 -0000
Are U a rude clown who ran out of clever jokes with no laughing/paying audience?Fix it - run 4 office, cheat & win!
I got 2 more bitches arguing on my timeline rt now, how the fuck u gon type out an argument?? LOL, I see chicks gettin no better in #2010
cnoaht (Christopher Edward) Wed, 16 Dec 2009 20:02:19 -0000
I got 2 more bitches arguing on my timeline rt now, how the fuck u gon type out an argument?? LOL, I see chicks gettin no better in #2010
@Robsessed83 ya done good. I'm gonna go on vacay for a while. U keep that cape and keep saving those lost souls out there.
tinkrbe1l3 (Tinker Bell) Wed, 16 Dec 2009 20:02:19 -0000
@Robsessed83 ya done good. I'm gonna go on vacay for a while. U keep that cape and keep saving those lost souls out there.
@Anthoonys haha u dumbbb
MervDiggity_011 (Merv Lindsay) Wed, 16 Dec 2009 20:02:19 -0000
@Anthoonys haha u dumbbb
@WestlifeTwinkle why u hate lady gaga?
Neoark25 (Ahmed Alhussaini) Wed, 16 Dec 2009 20:02:19 -0000
@WestlifeTwinkle why u hate lady gaga?
@jus_q heeeeeeeey Sister Q!!!!! What are u doing?!?!?!
1stGlamazon (Yazmine) Wed, 16 Dec 2009 20:02:19 -0000
@jus_q heeeeeeeey Sister Q!!!!! What are u doing?!?!?!
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