Re: [Phys-l] FW: universal gravitation lab

[Roger Haar <haar@physics.arizona.edu>]

Hi,

	We do OK with reducing vibrations.  Our balance is mounted on a 3-4 ft 
high column, which is constructed of 1 ft cubes of concrete separated by 
vibration damping pads (like McMaster-Carr part # 5998k4 www.mcmaster.com)

	Once, I poured a 6" thick pad on concrete on top of a small Steelcase 
desk.  I had planned to add vibration damping pads between the concrete 
and the desk, but the faculty member was happy  without this addition 
for his atomic force microscope.  ( I made a form, placed it on the 
desk, and mixed up seven bag of concrete mix.  I figure it is 350-400 
lb)  The story is if you can decouple a little bit from the source of 
vibrations, mass usually helps.

	One could also try the methods in John Strong's  classic, "Procedures 
in Experimental Physics".

Thanks
Roger Haar U of AZ Physics

*****************************************************************
Paul Lulai wrote:
> Man, I hated the execution of the Cavendish experiment.  Not only come
> in at night *but also* try to time the buildings HVAC system to get a
> good run... Arrgh.
>
> Paul Lulai
> Physics Instructor & Online Learning Coordinator
> Saint Anthony Village Senior High School, ISD 282
> 3303 33rd Avenue N.E.
> Saint Anthony Village, MN 55418
>  
> (w) 612-706-1144
> (fax) 612-706-1140
> -----Original Message-----
> From: phys-l-bounces@carnot.physics.buffalo.edu
> [mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of William
> Maddox
> Sent: Monday, February 12, 2007 10:33 AM
> To: Forum for Physics Educators
> Subject: Re: [Phys-l] FW: universal gravitation lab
>
> From: WC Maddox
>
> If anyone wants to do a real equipment experiment involving gravity, 
> Tel-Atomic has a version of the Cavendish experiment that uses a 
> computer to analyze the data. The apparatus cost ~ $2,000. In the 
> past this experiment often didn't get done due to the weakness of the 
> force and the sensitivity of the apparatus to vibration. If anyone 
> wanted to do it when I took advanced lab they had to come in at night.
>
> End Message
>
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