Naked Science Forum

General Science => General Science => Topic started by: stana on 09/06/2007 11:44:04

Title: Frequency Sounds
Post by: stana on 09/06/2007 11:44:04

Hi, i`m not sure if this is the right forum, so if anyone could correct me..thanks.

I heard that younger people are on different wave frequencies to older people, is this true? and is it true that there is some things only younger people than hear, and older people cant? If so, can someone give me a link to something, so me and an older freind can see if it actually works.

PS. Ive heard that when you hear a noise, and your ears tingle it means that youl never hear that sound again, is that also true?

thanks

Title: Frequency Sounds
Post by: dentstudent on 11/06/2007 08:21:51

I know that a child can hear a much broader range of frequencies than an adult, and this range diminishes all the way through your life. From birth, you can hear perhaps from 20 Hz to 30,000 Hz, which by adulthood will reduce to 20,000 Hz. Here'a link to some further explanation:

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/earsens.html

I did hear about a year ago, that in the UK, a noise was going to be used to disperse groups of teenagers which was pitched where only they could hear it. This noise was played over the radio and to a teenage studio guest, and she heard a nasty sort of "white" noise (like you get on the TV when it's not tuned in). I didn't hear anything..........

Title: Frequency Sounds
Post by: daveshorts on 11/06/2007 10:17:52

yes when I was 15 or so I could hear up to about 20kHz (which I think is normal) but now at almost 30 I can only hear up to about 17kHz.

Your external ears, eardrums, the funky little bones are all ways of transferring vibration to your cochlear. This is a snail shaped structure with lots of sensitive little hairs in it. At the wide mouth it detects low frequencies, and at the narrow top it resonates at high frequencies. It does this by the  vibration moving the hairs which then send a signal back to your brain. The high frequency hairs get damaged over the years and stop working so the highest frequency you can hear reduces with time.

Title: Frequency Sounds
Post by: paul.fr on 11/06/2007 10:21:34

Quote from: daveshorts on 11/06/2007 10:17:52

yes when I was 15 or so I could hear up to about 20kHz (which I think is normal) but now at almost 30 I can only hear up to about 17kHz.

Your external ears, eardrums, the funky little bones are all ways of transferring vibration to your cochlear. This is a snail shaped structure with lots of sensitive little hairs in it. At the wide mouth it detects low frequencies, and at the narrow top it resonates at high frequencies. It does this by the  vibration moving the hairs which then send a signal back to your brain. The high frequency hairs get damaged over the years and stop working so the highest frequency you can hear reduces with time.

I also seem to remember that, people with darker skin have a better hearing range.

Title: Frequency Sounds
Post by: dentstudent on 11/06/2007 10:25:03

Quote from: daveshorts on 11/06/2007 10:17:52

The high frequency hairs get damaged over the years and stop working so the highest frequency you can hear reduces with time.

And also that prolonged exposure to loud noises will also reduce your ability to hear.

Title: Frequency Sounds
Post by: guest6180 on 11/06/2007 12:41:46

The sound you were referring to is called the mosquito.  For a while it did work as a "youth deterrent" but then the sneaky young things got wise and started to use it as a ring tone so that their teachers wouldn't be able to tell if they used their phone in class!!

Title: Frequency Sounds
Post by: dentstudent on 11/06/2007 13:06:32

I'm not so sure....do you mean the "mosquito" as in nasty bitey pain in the ass insect, or "mosquito" name given to noise to get rid of nasty bitey pain in the ass teenagers?  [;D]