Comment author:SilasBarta
23 March 2010 05:49:46PM
*
6 points
[-]
Do you remember what insight helped you to overcome these questions? My experience with Level 1 -> Level 2 transitions is that I somehow mysteriously got used to the phenomenon, without knowing exactly how that happened. Also, I am not sure how could I explain the Doppler effect to somebody at Level 1, or answer questions such as the ones above. It seems that explanations reliably work up to Level 1 only.
I don't remember when I finally got a "Level 2" answer, but to move someone else in that direction, I would explain it this way: First, make sure they understand what's actually happening in a compression wave in air. Help visualize it with a slinky if necessary. Then say,
"The sensation of sound comes from when your ears recognize a quick sequence of compressed-air, less-compressed-air, compressed-air, less-compressed-air, etc. And the rate at which this sequence cycles determines the pitch you hear, with quicker cycling meaning a higher pitch.
"If the source of the sound isn't just standing still, but moving toward you, then each compression it makes of the air happens at a point where it is closer to you that it was before, so that bit of compressed air hits you sooner than otherwise. So as the compressed/less-compressed groups reach you, they cycle through faster, which you experience as a higher pitch, for the same reason you'd experience anything as a higher pitch."
(Someone let me know if I'm seriously off; it's been a while.)
Comment author:srjskam
15 June 2010 09:17:16PM
3 points
[-]
My first instinct would have been something like that, but on second thought, I'd start with a example of a boat moving in water and the waves it makes, maybe drawing a picture and ask them to visualize it. This is admittedly very crude and inaccurate, but gives a good overview of the phenomenon. After that I'd elaborate on the differences of surface waves vs. pressure waves, wavelength & frequency and anatomy of hearing etc.
Generally speaking (and not directed against anything anyone has said): give the explainee an intuitive framework to hang details on, don't pour a litany of seemingly unconnected facts. Just make sure he doesn't confuse the crude framework for the actual phenomenon.
(...And more generally: of course, the best would be to explain in a mode that is natural for the individual... for me (and, I assume, quite a few others) it's visuality & real-world analogies.)
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I don't remember when I finally got a "Level 2" answer, but to move someone else in that direction, I would explain it this way: First, make sure they understand what's actually happening in a compression wave in air. Help visualize it with a slinky if necessary. Then say,
"The sensation of sound comes from when your ears recognize a quick sequence of compressed-air, less-compressed-air, compressed-air, less-compressed-air, etc. And the rate at which this sequence cycles determines the pitch you hear, with quicker cycling meaning a higher pitch.
"If the source of the sound isn't just standing still, but moving toward you, then each compression it makes of the air happens at a point where it is closer to you that it was before, so that bit of compressed air hits you sooner than otherwise. So as the compressed/less-compressed groups reach you, they cycle through faster, which you experience as a higher pitch, for the same reason you'd experience anything as a higher pitch."
(Someone let me know if I'm seriously off; it's been a while.)
My first instinct would have been something like that, but on second thought, I'd start with a example of a boat moving in water and the waves it makes, maybe drawing a picture and ask them to visualize it. This is admittedly very crude and inaccurate, but gives a good overview of the phenomenon. After that I'd elaborate on the differences of surface waves vs. pressure waves, wavelength & frequency and anatomy of hearing etc.
Generally speaking (and not directed against anything anyone has said): give the explainee an intuitive framework to hang details on, don't pour a litany of seemingly unconnected facts. Just make sure he doesn't confuse the crude framework for the actual phenomenon.
(...And more generally: of course, the best would be to explain in a mode that is natural for the individual... for me (and, I assume, quite a few others) it's visuality & real-world analogies.)
(And hello, everyone. First post.)