OT; Forced Resonance

[bfish]

Interesting viddie demo on PopSci;

http://www.popsci.com/breakdown/arti...cillate-wildly

That's almost enough to strip my gears...

Added;
After watching it a few more times, it appears that having an odd number of 'nomes with random phase is key to the effect. When placed on the cans, the platform reacts to the majority, creating a side to side sway that brings all into phase. Were the experiment performed with an even number of 'nomes equally out of phase (say 4 'nomes at 90 degrees each respectively) they should cancel and continue their preset beat.

Still pretty cool though.

Added later;
The axis of movement is obviously also key in the vid. Would the same effect occur if you substituted 4 solid balls for the 2 can "rollers", and oriented the 'nomes at random different axes?

<font color="#FFFFFF" size="1">[ June 24, 2008 04:38 PM: Message edited by: bfish ]</font>

[mah]

Hey bfish,

I think you have revealed the secret behind Acoustimas - smaller metronomes, of course.

[mah]

bfish,

Multiple loudspeakers in the one enclosure would be an example if their parameters were not identical. The effect would be swamped by the amp drive.

[Steve Mac]

Actually women grouped together whose time of the month starts aligning may be forced resonance too.

[bfish]

I'm not so sure. I'm having trouble relating the effect to any real world phenomena besides balanced crankshafts and buildings.

I sure wish I could have learned some technique to control a metronome when I was a kid taking piano lessons though...I hated those things.

[bowtie427ss]

I'm not so sure. I'm having trouble relating the effect to any real world phenomena besides balanced crankshafts and buildings.

<font size="2" face="Verdana, Helvetica, sans-serif">Tacoma Narrows bridge maybe?

[ame="http://www.youtube.com/watch?v=j-zczJXSxnw"]YouTube - Tacoma Narrows Bridge Collapse "Gallopin' Gertie"[/ame]

[bfish]

Good points. Bonus points to Steve and Bow for using analogies I can really relate to...when my ex went out of phase, every bridge in the county started swaying.

Metronomes, women's moods, and falling bridges...Hunter Thompson didn't scratch the surface of Fear and Loathing...

tick...tick...tick...tick...

"Do these slacks make me look fat?"

tick
.....tick
........tick
............tick
.................tick.."Arch those fingers, young man! Sit up straight! Now play it again..."

I'm
f
..a
....l
......l
........i
..........n
.............g

"The cucumbers taste like Clorox because I soaked them in Clorox, stupid!"

tick...tick...tick...

I feel a nightmare coming on...

<font color="#FFFFFF" size="1">[ June 25, 2008 11:16 PM: Message edited by: bfish ]</font>

[Mike Gibson]

Stepping into my Wayback Machine I seem to remember getting this big lecture about breaking step when crossing a bridge in bootcamp.

Naturally we'd try and get everyone to march in step but you know how that went. They called it sympathetic vibration. Which struck me as odd since those Company Commanders were anything but sympathetic.

Feesh, all you need to do is find the resonant frequency of of Walleye and you're home free

[bfish]

Yeah Mike, sympathetic vibration seems a more fitting descriptor for sure. I just see no real resonance in the vid as the article describes. The 'nomes are merely a periodic source that the suspended platform responds to, which in turn influences the period of the 'nomes.

Originally posted by Mike Gibson:
Feesh, all you need to do is find the resonant frequency of Walleye and you're home free

<font size="2" face="Verdana, Helvetica, sans-serif">Done that. I call it large signal impulse response, or The Big Click...

Actually though, the electrofishing boys have it pretty well pinned down to the 50-60 cycle range of pulsed DC.

My resonant frequency? Well, I found that back in '76 at the prom, standing in front of some A7s and a Leslie for the first time. Been resonating to both ever since...

<font color="#FFFFFF" size="1">[ June 27, 2008 01:11 AM: Message edited by: bfish ]</font>