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Re: [Phys-l] Rubens Tube



Interesting thought. There are flowmeters operating on a similar principle.
They invariably use tapered tubes to indicate variation in pressure.
I suspect that a ping pong ball in a cylindrical pipe would be hard to hold
in position: there might be a need for a small hole at the low point,
and several small holes at the desired high point, to maintain some
stabilization. Supposing the amplitude of the indication is low, there
might also be a need for a big funnel for the diaphragm, in order to
increase the modulation.

Brian W

At 10:28 PM 4/10/2008, you wrote:
I've been thinking of trying to build a flameless Ruben's Tube using
ping-pong balls, clear acrylic tubes that would allow the balls to 'float',
and a compressed air source. Has anyone tried this approach or does anyone
foresee any catastrophic problems with the idea?

Matt Coia

On Thu, Apr 10, 2008 at 8:51 PM, Bernard Cleyet <bernardcleyet@redshift.com>
wrote:

> If one reads the archive: I suggested PVC using stainless steel
> nipples to "isolate" the "heat". I suspect the combo of your heat
> dissipation and the SS insulation would be a permanent "fix".
> Everyone on the list nixed my idea and gave sources for metal pipe,
> or wrote nothing.
>
> bc semi-vindicated, and thinks Josh should "join" tap-l.
>
>
> On 2008, Apr 10, , at 17:12, Josh GATES wrote:
> > My PVC Ruben's tube didn't melt, because I put a 2 inch wide strip of
> > folded-over (a few times) tin foil along the axis with the holes. I
> > drilled the holes through the tin foil. It conducted the heat away
> > nicely. Occasionally I would have to redrill to clear out a few of
> > the
> > individual holes that melted a bit, but it wasn't bad. However,
> > the tube
> > will eventually bow upwards, especially if you use it for extended
> > periods. It got to the point that I couldn't use it anymore after
> > 20 uses.
> >
> > Josh Gates
> > Stoneleigh-Burnham School
> > Greenfield MA
> >
> > Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu> on
> > Thursday, April 10, 2008 at 6:45 PM -0500 wrote:
> >> And it didn't melt?
> >>
> >> bc suggest asking the tap-l people; they evidently all have one.
> >>
> >> Archive:
> >>
> >> http://lists.ncsu.edu/cgi-bin/digest?list=tap-l&archive=tap-l.
> >> 200803&Submit=Show+Archive
> >>
> >>
> >> p.s. The history and detailed construction of his* tube:
> >>
> >>
> >> http://en.wikipedia.org/wiki/Rubens'_Tube
> >>
> >>
> >>
> >>
> >>
> >> * Heinrich Rubens
> >>
>
> cut
> >
>
> _______________________________________________
> Forum for Physics Educators
> Phys-l@carnot.physics.buffalo.edu
> https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
>
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Brian Whatcott Altus OK Eureka!