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Home » Santa Clarita News » Environment » SCV Outdoor Report » Santa Clarita Valley Outdoor Report: Speed Of Sound
Santa Clarita Valley Outdoor Report:  Speed Of Sound

Santa Clarita Valley Outdoor Report: Speed Of Sound

What do bats and toothed whales have in common?  Certainly not size, not habitat, and not even how they get from one place to another. 

But they both hunt using sound waves to locate their prey, a technique known as echolocation.  A recent report from the University of Southern Denmark concludes “that bats and toothed whales produce signals for echolocation in the same frequency range, from 10 to 200 kHz.”

 

Our local gray whale is a baleen whale, not to be confused with toothed whales.  They use sound for communication, not hunting.

Why would animals who are so dissimilar rely on a similar sound frequencies for locating food?  To explain this, I’m going to use a bit of math.

The first thing to keep in mind: sound travels about 5 times faster in water than it does in air.  According to this University of Rhode Island website:  “Sound travels about 1500 meters per second in seawater” and “about 340 meters per second” in air. This is because molecules that are closer to one another transmit sound faster; water is denser than air, so sound waves move faster in water.

The second thing to keep in mind:  Speed of sound = frequency x wavelength.

The third thing to keep in mind: “The shorter the wavelength, “the more information you can get about the target.”  A hunter needs to know the direction and size of it’s target.

Now…for the math…if the speed increases but the frequency remains the same, the wavelength increases.  And if the wavelength increases, you get less information about the target.  Simply put, it looks like this:

 

 

Speed   =

Frequency  X

Wavelength

 

Target Info

Air

4

2

2

 

More

Water

20

2

10

 

Less

 

So there’s a trade-off between sound speed and the amount of information provided.  Which means, no matter whether you are a bat, hunting in the air for a tiny, agile target like a mosquito, or a toothed whale, hunting in the water for a larger target like a seal, you will rely on the same range of sound frequency.

Just out of curiosity, I decided to check the frequency of some commonly used communications equipment.  Good news!  There’s no overlap with the 10-200 kHz frequency range of bats and tooth whales.  And this includes our local station, KHTS; our frequency is 1220 kHZ.  We’re only hunting for listeners.

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Upcoming Outdoor Events: 

Trail Maintenance Schedule.  Come join our volunteers as they help maintain our trails.  Contact Steve at machiamist@aol.com for time and place.

Wednesday mornings, November 6, 13, 20 & 27.
Saturday mornings, November 9 & 23.

2014 PlaceritaCanyon Wild Flower Calendar.  Looking for a unique and local gift?  For $10, the Docents and Volunteers at PlaceritaCanyonNatureCenter are offering a calendar filled with original photos of local wild flowers.  Best of all, your purchase will help support their fine work at the PlaceritaCanyonNatureCenter. They are available at the Placerita Canyon Nature Center Gift Shop.

New trail maps available.  If you’d like to explore a bit on your own, the City of Santa Clarita has a website with trail maps of our local open spaces.

There’s also a new website for bicycle riders.  

Ask Dr. Norm:  Do you have questions about the flora, fauna, animals, rocks, etc. in our Santa Clarita Valley?  Here’s a place for you to ask your questions.  Dr. Norman Herr, Ph.D., is a professor of science and computer education at CaliforniaStateUniversity, Northridge.

Tell Us About Your Hike:  Here’s a new website where you can post pictures, provide feedback and make suggestions about the City of Santa Clarita’s trails and open spaces.

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You can listen to stories like this every Friday morning at 7:10 a.m. on “The SCV Outdoor Report”, brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.

For the complete MRCA hike and activity schedule and for trail maps, click here or go to LAMountains.com.    

Or check out our Facebook page  – L.A. Mountains.

 


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Source: Santa Clarita News


Santa Clarita Valley Outdoor Report: Speed Of Sound

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