Re: [Phys-l] Strobe makes aluminum can go "ting"

[Bernard Cleyet <bernardcleyet@redshift.com>]

There are a number of variation to this, one my perform to narrow the 
cause of the effect.

First off cover the lens or what ever is the the ambient illumination 
detector.  Thereby one obtains consistently max. power to the lamp.  
Then try various other receivers.  Hint I get, so far, the greatest 
response from a Sparks can on the black portion.  Try also thick white 
card only, black card, a black T shirt, the black plastic cover of a 
plug in the wall P/S.

The can is a new variation of the demo by Dean Baird at a meeting of the 
Bay (SF) Area Physics Alliance several years ago.

bc, knows it's emp, but in the tera frequency range, and prefers, "ping".

Tony wrote:

> I came across something interesting today with another physics teacher and I
> thought some of you might know how or why this is happening.
>
> Take an empty aluminum drink can and place a camera's strobe in front of the
> can. Face the light from the strobe at the can. Place the strobe about 1/2 a
> cm in front of the can. Charge and then trigger the camera strobe. When the
> flash occurs, you will hear a, "ting," sound from the can. The question is
> what is causing the sound?
>
> If I move the strobe about 3 cm away from the can and triggered, no sound is
> heard from the can.
>
> If I aim the strobe perpendicular from the can and trigger it, no sound is
> heard from the can.
>
> If I place the strobe about 1/2 cm in front of the can can place one sheet
> of notebook paper between the strobe and can the sound is diminished.
>
> If I place the strobe about 1/2 cm in front of the can can place six sheets
> of notebook paper between the strobe and can, no sound is heard.
>
> If I place the strobe about 1/2 cm in front of the can can place a piece of
> manila folder between the strobe and can, no sound is heard.
>
> If I try the flash from my digital camera I don't get any sound under the
> original working conditions. However my friend's digital camera works and
> well as my older (removable) camera strobe.
>
> At first we thought it was an and emp from the capacitor in the strobe's
> firing circuit. (But, I don't have a faraday cage handy to test this at the
> moment.) But now that I've done the experiments, above, I'm not so sure it
> is an emp. 
>
> Any ideas or thoughts?
>
> -Tony
>