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Re: Heating tape/Linear Expansion

Thanks for the detailed response, Karl

I checked your reference to the "H-17" linear expansion apparatus in
Sutton. I remember using this apparatus many years ago but had completely
forgotten about it. I seem to remember that the one I had was
manufactured by Cenco but it is not in their current catalog. I also
checked Fisher, and Sargent Welch catalogs also with no luck.
However, I found a similar apparatus Called Tyndall's Bar Breaker (Item
381-16) in Leybold's General Physics Catalog that is being distributed in
the USA by Klinger Educational Products (718 761 1822) .
I also found the old heavy-duty version in one of the older catalogs of
Griffin Science and Education division of England's Griffin and George
Ltd
(Item XHK-370-P Bar Breaking Apparatus). It breaks cast iron bars that
are about 6 cm long.



On Fri, 9 Oct 1998 12:40:48 -0500 (CDT) trappe@physics.utexas.edu (Karl
Trappe) writes:
For a view of the originally posted linear expansion device see:
http://www.ph.utexas.edu/~phy-demo/demo-txt/4a30-xx.html It has no
specific PIRA number (hence the xx notation) since it is rarely owned
by many universities.

The device described by Sam Sampere is more common. It is PIRA #
4A30.30
break the bolt. This demonstration is one of the top 500 lecture
demonstrations (as opposed to 4A30.10 bimetal strip and 4A30.20 ball
and ring which are top 200 lecture demonstrations in the category "Solid
Expansion" (PIRA #4A30.xx)

4A30.30 is described in several demonstration manuals: (H-17 in
Sutton,
Ha-10 in Frier and Anderson, Disc 14-10 of the Video Encyclopedia of
Demonstrations). The Physics Demonstration Bibliography is the source
of
this information. AAPT promises to attempt to have it available for
purchase around January, 1999. It has been in preparation for over
10
years by Physics Instructional Resource Association members (An
Affiliate
Society of AAPT).

PIRA is online at: http://cavern.uark.edu/depts/pira/

Other useful resources may be located via the UTEXAS Lecture Demo
Homepage
(Andrew Yue) at: http://storm.ph.utexas.edu/~phy-demo/

There you will find "Demonstration Resources at Other Universities" (a
list
compiled by Keith Warren of NCState at the location:
http://www.ph.utexas.edu/~demog/resources.html

Enjoy, Karl



On Thu, 08 Oct 1998 22:55:52 -0400 Sam Sampere
<sampere@suhep.phy.syr.edu> writes:
Why not Herb. Can't you build it and transform the angle change
into
a linear displacement?? My version uses gas flames to heat a steel
rod.
The rod expands and busts an iron bar. No measurements here, just
proof
of themal expansion. Loud and dramatic.

This sounds GREAT!!!
Why don't you write it up (with photos) for publication in The
Physics
Teacher?
Meanwhile please let me have further details on the set up. How are
the
bars anchored and clamped?

Herb Gottlieb
herbgottlieb@ juno.com FAX 718 224 4764




Herbert H Gottlieb wrote:

On Thu, 08 Oct 1998 23:54:39 -0700 Ron Ebert
<ebert@citrus.ucr.edu>
writes:

We have a lecture demonstration which qualitatively demonstrates
the coefficient of expansion. It shouldn't be hard to adapt it as a
lab where the students can carry out quantitative measurements. It
consists of a long aluminum rod fixed at one end with a bench clamp.
The
other
end rests on a wood block, but between the rod and the block is a
needle
set
perpendicular to the rod. The end of the needle extends out past
the edge of the table, and affixed to it is a large paper arrow.
When
the aluminum
rod is heated with a burner, the arrow will rotate noticeably.
Ron...
This sounds like an easy to prepare demo with excellent
visibility
for large lecture halls. I'm going to show it at the next meeting of
the

New York City Physics Teachers .... and giving you full credit for
the
suggestion. However it seems to demonstrate that an aluminum rod
will lengthen as it is heated. As you say...it is not easy to use
this
apparatus for determining the coefficient of linear expansion.

Herb Gottlieb from New York City
(Where we invite you to see Ron's expansion demo at our next
physics teachers' meeting at New York University on Friday evening,
October
23.)

Dr. Karl I. Trappe Desk Phone: (512)
471-4152
Physics Dept, Mail Stop C-1600 Demo Office: (512)
471-5411
The University of Texas at Austin Home Phone: (512)
264-1616
Austin, Texas 78712-1081