I can hear you whisper..... from 50 feet away.

[science_spot]

Is this possible?  Can you hear a whisper from 50 feet away?  Could you, if you had super ears like a cat, or maybe some fancy microphone equipment?  What if you had a parabolic reflector, used as a listening vessel?

Until this past weekend, I had never heard the term parabolic reflector, and I probably would not have been able to identify it as an object that can be used as a listening vessel.  A parabolic reflector is shaped like a bowl (concave dish) so that it reflects waves into a common focal point.  This dish can be used to collect sounds from a distant place, such as signals from stars.  The most well known parabolic reflector is the satellite dish.  Parabolic reflectors can also be used to concentrate solar heat waves onto a common point, which is useful in some solar cooking systems.

The coolest thing about our little lesson at the museum?  it wasn't "little" at all. The parabolic reflectors in the display were HUGE, considering they were inside the museum, and they were designed so you can sit in it, with your ears roughly at the focal point!  Here is a picture of Abby (and Lola, a bear from her kindergarden class's project about hosting a friend).  As you cansee, they are sitting inside a giant parabolic reflector.  I was sitting in the other one (50 feet away), talking to her in a whisper, which she could easily hear thanks to concentration of the sound waves by this huge device.  Really really cool!

 

 

This website shows how you can make your own parabolic reflector, specifically for the purpose of solar cooking (which is explained in the link at the bottom of the tutorial).  This is a great activity to compliment any physics lession regarding wave transmission or sound.

 

Tonya

The Science Spot

 

[Busymama07]

Nov. 20, 2009 at 3:54 PM

That is so cool!!!

[Lb128f]

Nov. 20, 2009 at 4:21 PM

Cool, thanks for sharing!

[justanotherjen]

Nov. 20, 2009 at 6:47 PM

We have a set up at the Museum of Science and Industry here in Chicago.  I always thought it was pretty darn cool when I was a kid and my kids had a blast with it.  The one at our museum is smaller with 2 plastic dishes...no clue how far apart they are but it's so cool to stand in them and hear the other person even with all the museum noise and people walking in and out of the display (it's right in the middle of a narrow hallway).