<story><title>Calgary student has been studying decibel levels in hand dryers since age nine</title><url>https://www.cbc.ca/news/canada/calgary/calgary-student-nora-keegan-hand-dyer-research-decibel-1.5185853</url></story><parent_chain><item><author>simias</author><text>That&amp;#x27;s very possible indeed. I remember when I was a kid my grandparent&amp;#x27;s tube TV was making a high-pitched sound that was figuratively driving me insane (maybe generated from the HSYNC frequency, now that I think about it). I couldn&amp;#x27;t understand how they could bear it but of course when I told them they didn&amp;#x27;t get it because it was probably way outside of their hearing range. I&amp;#x27;m fairly sure that now that I&amp;#x27;m in my 30s I couldn&amp;#x27;t hear it either.</text></item><item><author>JoeAltmaier</author><text>Also, we hear using the cochlea, a spiral sense organ that sorts sound by frequency. In children the whole thing is much smaller. So they hear much-smaller wavelengths of sound which means higher-pitched sound. As we grow so does the cochlea so we hear lower and lower sounds and lose the sensitivity to the highest-pitched ones?&lt;p&gt;I&amp;#x27;m guessing that hair dryers have a scream in the upper register that adults don&amp;#x27;t normally hear.</text></item><item><author>akerro</author><text>That&amp;#x27;s not the only reason why children hear more and louder. When you&amp;#x27;re in your &amp;#x27;30s you already have a minor hearing loss, you don&amp;#x27;t hear all sounds and noises then you did when you were 5. Children see more colours as well.</text></item><item><author>tda</author><text>My kids get nervous as soon as they even see a hand dryer. They start crying when it&amp;#x27;s on. I thought they were exaggerating, it never occurred to me that sound levels for kids are different because they are smaller (though it makes complete sense). That, coupled with higher sensitivity to noise and more delicate hearing canals of youngsters kind of make me feel like a bad parent for trying to let them use the dryers anyway (Even though I have long since given up). This kids research proves my kids right, and I am not easily convinced ;) Great accomplishment for I should listen to my kids.&lt;p&gt;Already an impressive combination of curiosity and perseverance to get a scientific paper published for any non-academic, let alone a 13 year old!!&lt;p&gt;edit: The absolute worst things are these &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.ehanddryers.com&amp;#x2F;hand-dryers&amp;#x2F;tap-hand-dryers&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.ehanddryers.com&amp;#x2F;hand-dryers&amp;#x2F;tap-hand-dryers&lt;/a&gt;, my kids just plain refuse to wash their hands out of fear of accidentally triggering the dryer</text></item></parent_chain><comment><author>papln</author><text>&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;The_Mosquito&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;The_Mosquito&lt;/a&gt;&lt;p&gt;&amp;gt; The Mosquito or Mosquito alarm is a hand wound machine used to deter loitering by young people by emitting sound at high frequency, in some versions so it can be heard mostly by younger people.&lt;p&gt;&amp;gt;  The sound was made into a mobile phone ringtone, which could not be heard by teachers if the phone rang during a class.</text></comment>
<story><title>Calgary student has been studying decibel levels in hand dryers since age nine</title><url>https://www.cbc.ca/news/canada/calgary/calgary-student-nora-keegan-hand-dyer-research-decibel-1.5185853</url></story><parent_chain><item><author>simias</author><text>That&amp;#x27;s very possible indeed. I remember when I was a kid my grandparent&amp;#x27;s tube TV was making a high-pitched sound that was figuratively driving me insane (maybe generated from the HSYNC frequency, now that I think about it). I couldn&amp;#x27;t understand how they could bear it but of course when I told them they didn&amp;#x27;t get it because it was probably way outside of their hearing range. I&amp;#x27;m fairly sure that now that I&amp;#x27;m in my 30s I couldn&amp;#x27;t hear it either.</text></item><item><author>JoeAltmaier</author><text>Also, we hear using the cochlea, a spiral sense organ that sorts sound by frequency. In children the whole thing is much smaller. So they hear much-smaller wavelengths of sound which means higher-pitched sound. As we grow so does the cochlea so we hear lower and lower sounds and lose the sensitivity to the highest-pitched ones?&lt;p&gt;I&amp;#x27;m guessing that hair dryers have a scream in the upper register that adults don&amp;#x27;t normally hear.</text></item><item><author>akerro</author><text>That&amp;#x27;s not the only reason why children hear more and louder. When you&amp;#x27;re in your &amp;#x27;30s you already have a minor hearing loss, you don&amp;#x27;t hear all sounds and noises then you did when you were 5. Children see more colours as well.</text></item><item><author>tda</author><text>My kids get nervous as soon as they even see a hand dryer. They start crying when it&amp;#x27;s on. I thought they were exaggerating, it never occurred to me that sound levels for kids are different because they are smaller (though it makes complete sense). That, coupled with higher sensitivity to noise and more delicate hearing canals of youngsters kind of make me feel like a bad parent for trying to let them use the dryers anyway (Even though I have long since given up). This kids research proves my kids right, and I am not easily convinced ;) Great accomplishment for I should listen to my kids.&lt;p&gt;Already an impressive combination of curiosity and perseverance to get a scientific paper published for any non-academic, let alone a 13 year old!!&lt;p&gt;edit: The absolute worst things are these &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.ehanddryers.com&amp;#x2F;hand-dryers&amp;#x2F;tap-hand-dryers&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.ehanddryers.com&amp;#x2F;hand-dryers&amp;#x2F;tap-hand-dryers&lt;/a&gt;, my kids just plain refuse to wash their hands out of fear of accidentally triggering the dryer</text></item></parent_chain><comment><author>h2odragon</author><text>15Khz colorburst whine. Its amusing how many audio recordings even today show a notch filter used at that frequency, years after there were no CRTs anywhere in the recording process.</text></comment>