Things to ponder:
If PIN stands for Personal Identification Number, why do we call it a PIN
number?
Why isn't phonetic spelled the way it sounds?
Fact of the day:
Flamingos are naturally white. Their diet of brine shrimp and algae turns
them pink.
Five Sounds You can Not Hear
Think you have perfect hearing? There are still plenty of sounds in the
world that you can't detect. The low range of human hearing starts around 20
hertz, and tops out at about 20,000 [
By contrast, bats can hear ultrasonic sounds with frequencies up to 110,000
hertz . Other animals, like elephants, hear sounds many times lower than
those a human can perceive. And as people age, their hearing gets even
worse, eliminating even more sounds from the range of audible noises. Here
are just a few sounds most people are missing out on:
1. Sounds for young people
As humans age, their hearing changes. Age-related hearing loss, called
presbycusis, means that older people can't hear some high-pitched sounds
they would have heard in their youth. Most people over the age of 18 cannot
hear the 17,400 hertz tone in the video above.
2. Music designed for cats
In 2014, activists from Pussy Riot rigged an electric piano to play music
designed specifically for cats. Cats possess ultrasonic hearing, meaning
they can hear a much wider frequency of sounds than humans (or most other
mammals, for that matter) can Although people could hear portions of the
concerto
<http://mentalfloss.com/article/52633/why-these-11-bands-wear-masks> Pussy
Riot staged to protest Internet censorship,
<http://mentalfloss.com/article/52633/why-these-11-bands-wear-masks>
http://mentalfloss.com/article/52633/why-these-11-bands-wear-masks
the melody is a whole lot more complex from the feline point of view. For
what it's worth, the cats seemed to enjoy it. Research has shown that cats
are pretty into feline-specific tunes, in general. (We have some
<http://mentalfloss.com/article/61990/scientists-have-composed-music-your-ca
ts> video evidence) found at the next link,
http://mentalfloss.com/article/64572/5-sounds-you-probably-cant-hear
3. A dog-specific Beatles' song
In the Beatles' song "A Day in the Life," the band included a whistling
noise at a frequency of 15,000 hertz right after the last chord of the song,
designed to be heard by canine Beatles fans. "We'd talk for hours about
these frequencies below the sub that you couldn't really hear and the high
frequencies that only dogs could hear. We put a sound on Sgt. Pepper that
only dogs could hear," Paul McCartney told the BBC in 2013. (The sound
starts just after the 5-minute mark.)
4. Ultrasonic finger friction
When you gently rub your thumb and index finger together, the friction
creates an ultrasonic signal
When you gently rub your thumb and index finger together, the friction
creates an ultrasonic signal The action is a useful way to test out the
function of a <http://www.batsound.com/?p=2> bat detector, which converts
ultrasonic sound from bat echolocation into noise humans can hear. In the
book
<https://books.google.com/books?id=UGjtXW4eoNkC&pg=PA131&lpg=PA131&dq=bat+ec
holocation+finger+rub&source=bl&ots=l8ltkkkVnP&sig=dspvQjHg4G4guXmCspHavXpJV
t0&hl=en&sa=X&ei=6K5sVfD6F8e1sASL7oJQ&ved=0CEoQ6AEwBg#v=onepage&q=roeder&f=f
alse> Insects Through the Seasons,
Find at this link to buy:
<https://books.google.com/books?id=UGjtXW4eoNkC&pg=PA131&lpg=PA131&dq=bat+ec
holocation+finger+rub&source=bl&ots=l8ltkkkVnP&sig=dspvQjHg4G4guXmCspHavXpJV
t0&hl=en&sa=X&ei=6K5sVfD6F8e1sASL7oJQ&ved=0CEoQ6AEwBg#v=onepage&q=roeder&f=f
alse>
https://books.google.com/books?id=UGjtXW4eoNkC&pg=PA131&lpg=PA131&dq=bat+ech
olocation+finger+rub&source=bl&ots=l8ltkkkVnP&sig=dspvQjHg4G4guXmCspHavXpJVt
0&hl=en&sa=X&ei=6K5sVfD6F8e1sASL7oJQ&ved=0CEoQ6AEwBg#v=onepage&q=roeder&f=fa
lse
entomologist Gilbert Waldbauer writes that pet bats can be trained to
respond to the sound, and fly toward it.
5. Infrasonic elephant calls
<http://www.upali.ch/communication_en.html> distances of more than a mile.
Listen to an example of these elephant rumbles from the
<http://www.birds.cornell.edu/brp/elephant/cyclotis/language/infrasound.html
Elephant Listening Project.
http://www.birds.cornell.edu/brp/elephant/cyclotis/language/infrasound.html
