Jay-qu Posted July 13, 2009 Report Share Posted July 13, 2009 ************************************************************************A duck's quack doesn't echo, and no one knows why.************************************************************************sorry not true MythBusters (2003 season) - Wikipedia, the free encyclopedia It is because the ducks quack has an acoustic structure that coincides with its echos Quote Link to comment Share on other sites More sharing options...
Boerseun Posted July 14, 2009 Author Report Share Posted July 14, 2009 sorry not true MythBusters (2003 season) - Wikipedia, the free encyclopedia It is because the ducks quack has an acoustic structure that coincides with its echosThat could only be destructive interference? Wouldn't the shape of the object against which it echoes scatter it so that it won't occur? Quote Link to comment Share on other sites More sharing options...
Jay-qu Posted July 14, 2009 Report Share Posted July 14, 2009 That could only be destructive interference? Wouldn't the shape of the object against which it echoes scatter it so that it won't occur?Its not destructive interference, sounds more like they mean constructive. Quote Link to comment Share on other sites More sharing options...
Boerseun Posted July 15, 2009 Author Report Share Posted July 15, 2009 Its not destructive interference, sounds more like they mean constructive.Sorry - I did not check the link, my bandwidth's a bit sucky right now and it keeps bombing out. But either ways, won't either destructive or constructive interference of the quack's echo be dependent on the reflecting surface being perfectly flat and pointing exactly at the source? Which you won't normally find in nature, where the myth presumably originated from? If not flat, it would be scattered so much that perfect interference would be impossible? Quote Link to comment Share on other sites More sharing options...
Jay-qu Posted July 15, 2009 Report Share Posted July 15, 2009 You make a good point B, and it will also depend on the distance to the object that is doing the reflecting.. So all I can say is a ducks quack will have an echo, but I dont know what to the guy was smoking that put forward such a conjecture :Alien: Quote Link to comment Share on other sites More sharing options...
DougF Posted July 20, 2009 Report Share Posted July 20, 2009 I watched the Show in Question also and at first thought that they were saying that the Ducks Quack had no echo, but what was said was: When examined by an audio-expert' date=' it was found that the echo was "swallowed" by the original quack, due to the very similar acoustic structure between the quack and the echo. Because of this, it may be difficult to tell where the quack ends and the echo begins. Normally, a sound and its own echo have very different waveforms on an oscilloscope. As it turns out, a duck's quack and its echo have a very similar waveform. Oscilloscope analysis of a duck's quack/echo could lead someone to mistake the echo waveform for part of the source waveform, due to the way in which they blend together. In the same way, human hearing may not perceive the difference between a duck's quack and its echo. [ Quote/'] MythBusters (2003 season) - Wikipedia, the free encyclopedia So in conclusion the Duck does have an Echo but you can't tell the Quack from the Echo !!!! :) :D :eek_big: :eek_big: :eek_big: :eek_big: :eek_big: :eek_big: Quote Link to comment Share on other sites More sharing options...
Boerseun Posted July 20, 2009 Author Report Share Posted July 20, 2009 Makes sense - a duck's quack is merely a pressure wave in air, like any other sound. And if there are any problems with it, like it not having an echo, the problem must lie with the human ear. Quote Link to comment Share on other sites More sharing options...
Boerseun Posted December 9, 2009 Author Report Share Posted December 9, 2009 While sitting at your desk, lift your right foot off the floor and make concentric clockwise circles. Now, while doing this, draw the number 6 in the air with your right hand. Your foot will change direction and there's nothing you can do about it.:naughty: Quote Link to comment Share on other sites More sharing options...
Michaelangelica Posted January 11, 2010 Report Share Posted January 11, 2010 You may already know that the tree Gingo biloba has survived unchanged for 180million years. It is the most ancient of flowering plants.But did you know that it is one of the few (only?) flowering plants with motile sperm-cells?(Source Cliltern seed catalog)Perhaps an idea that humans/mammals copied? Quote Link to comment Share on other sites More sharing options...
Jay-qu Posted March 25, 2010 Report Share Posted March 25, 2010 Things have been a bit quiet in this thread lately, heres another to get us restarted: The theoretical particles axions were actually named after a brand of detergent by Frank Wilczek, because they were introduced to 'clean up' a problem in quantum chromodynamics :shrug: Boerseun 1 Quote Link to comment Share on other sites More sharing options...
stereologist Posted March 25, 2010 Report Share Posted March 25, 2010 The Cavalieri estimator used in stereological studies gets its name from a 1902 paper in which one of Cavalieri's theorems was incorrectly applied. Although the present method does not use Cavalieri's theorem the name has stuck. Quote Link to comment Share on other sites More sharing options...
Michaelangelica Posted July 11, 2011 Report Share Posted July 11, 2011 http://www.sootoday.com/content/news/full_story.asp?StoryNumber=50683 Any explanations? Quote Link to comment Share on other sites More sharing options...
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