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ML Exhibit Noise


I am a long-time NCAR employee who remembers the days before the wonderful
exhibit involving a fan used to generate a vortex was installed in the
entry area of the Mesa Lab. In spite of the pleasure I take from that
exhibit, I miss the peace and quiet of those days. It is now necessary to
have the library doors closed to avoid distraction by the noise, which also
pervades the entire visitor area of the building. One only has to come in
after hours, when the fan is not in use, to be reminded of how pleasant
that area and the library can be.

I am wondering whether it would be possible to use a quieter fan, or
whether the exhibit could be started by a visitor, using a button, and run
on a timer for a few minutes whenever someone wants to see the exhibit in
operation. The rest of the time it would be off, and hence quiet.

Answered on August 18, 2000


In 1994 we received funding from NSF and a number of local foundations for
the specific purpose of enhancing the visitor and exhibits program. Through
the Exploratorium in San Francisco, we acquired seven highly interactive
exhibits that demonstrate scientific principles underlying many of the
research activities at NCAR. While the new exhibits created the intended
stimulating environment for visitors, we were aware that the tornado, in
particular, created some new problems, due primarily to the lack of
acoustic materials on surrounding surfaces. We worked closely with the
designer from the Exploratorium to investigate alternatives, and we
replaced the fan with a lower-powered one. The alternatives were limited by
both our altitude and Boulder's relatively low humidity levels, which
affect the creation of the vortex.

In response to the concerns of the questioner, we contacted the designer
again. After an extensive investigation, he was unable to find any new
alternative fans with quieter motors. However, he recalled the acoustic
reflectivity of the surrounding floors, walls, and ceiling and has
suggested some other actions that may reduce the noise level. A variety of
possible solutions include surrounding the fan with acoustic materials or
hanging such materials above the fan. We intend to pursue these suggestions
as soon as possible.

–Karon Kelly, Director, Information Support Services