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Re: Heating tape





On Thu, 08 Oct 1998 22:05:17 -0700 Glenn Knapp <kahuna@vcn.com> writes:

There is a variation on this demo (linear expansion) that replaces the
pointer with
a small mirror attached to a needle which the rod rests upon. You
reflect a laser
off the mirror onto the wall. When you heat the rod, the expansion
rotates
the needle/mirror assembly and the laser spot on the wall will move
dramatically. I've done it both ways, but the laser seems to have the
greater "wow" factor.

Glenn Knapp

Using the principle of optical amplification with the laser beam is well
known
but I had not thought of using it with the coefficient of linear
expansion lab or demo. It might prove to be a very practical solution for
improving a classic lab if heating tape and an inexpensive, reliable,
and precise temperature measurement instrument can be found.

The idea is certainly worth investigating as a student extra-credit
project!

Herb Gottlieb from New York City
(Where good physics projects are always needed for our students)