FOR IMMEDIATE RELEASE:             NIST 94-15
April 18, 1994

Contact:  Linda Joy                NIST SCIENTISTS HELP VISITORS
          (301) 975-4403           TO THE SMITHSONIAN'S SCIENCE
                                   IN AMERICAN LIFE EXHIBITION
                                   LEARN ABOUT LASERS AND ENZYMES


     How far away is the moon?

     How fast does light travel?

     How do detergent enzymes trounce laundry stains?

     Visitors to the Smithsonian's National Museum of American
History in Washington, D.C., will explore these questions at
hands-on experiment stations developed by scientists at the
Commerce Department's National Institute of Standards and
Technology for the museum's permanent new exhibition, "Science in
American Life."

     Three interactive displays created by scientists at NIST and
the Center for Advanced Research in Biotechnology will be part of
the exhibit opening April 27.

     Two NIST displays designed by research physicist John Travis
of Gaithersburg, Md.; physicist David King of Washington, D.C.;
and electronics engineer Alan Band of Derwood, Md., will teach
visitors about lasers and the speed of light.  The displays will
be located together in the exhibit's Hands On Science Center.

     A third interactive display, developed by NIST biologist
Travis Gallagher of Rockville, Md., will be in "Looking Ahead,"
an area focusing on the science and public perceptions of
biotechnology.  Gallagher prepared molecular images for this
interactive computer display at CARB, a research cooperative of
NIST, the University of Maryland Biotechnology Institute and
Montgomery County, Md.

     Two NIST displays will illustrate how scientists used
properties of light to measure the distance from the Earth to the
moon.  Travis, a research physicist in NIST's Chemical Science
and Technology Laboratory, designed a table-top display to
illustrate the advantages of laser light for measuring distance.
Using hand controls on the display, visitors will be able to
compare how white light and laser light travel over a distance.
They will also be able to pass a white light and a laser through
four color filters to illustrate how filters can reduce the
influence of moonlight on the experiment.

     Laser and white light also pass through a tank containing a
milky solution that illuminates the paths the light beams follow.
As light scatters off particles in the solution, different colors
are visible from different angles, Travis explains. 

     Next to this table-top display, another NIST experiment
allows visitors to calculate the actual distance to a target on a
picture of the moon approximately 25 meters away.  In this
display, designed by Band and King in the NIST Physics
Laboratory, visitors will use a control to aim the laser at a
reflector on the picture of the moon.  Laser pulses start a timer
on their way to the moon.  The reflector on the moon sends the
laser light back, which stops the timer.  A computer displays how
long it takes for a single pulse to travel to the reflector and
back, about 100 nanoseconds (100 billionths of a second.)

     A visitor can then multiply the time by the speed of light
in meters per second to calculate the distance the laser
traveled.  Directions and a calculator are provided at the
display.

     A third interactive display created at CARB will be located
in "Looking Ahead," a special area dedicated to biotechnology. 
The interactive display will introduce visitors to advances in
molecular biology and computer graphics and, at the same time,
familiarize them with a practical, everyday application of
biotechnology.

     Visitors will use a colorful computer graphics model
to explore the structure-function relationship between an enzyme
and a protein substrate.  The enzyme, subtilisin, is a common
laundry detergent additive that helps dissolve protein-containing
stains, such as blood or gravy, by cleaving the protein substrate
into smaller, more soluble pieces.  

     "Visitors will be able to move the substrate in three
dimensions to the docking site on the enzyme with touch-screen
controls," says Gallagher, the biologist who designed the
display. 

     The protein substrate appears to float in front of the
enzyme until it is placed in the docking position.  Whether or
not a visitor successfully guides the substrate to the docking
site, the final sequence of the computer display simulates the
enzyme cleaving a larger protein molecule.

     The three NIST interactive displays will be part of a large
permanent exhibition that traces the history of science in
American life from 1876 into the present and then looks ahead to
the 21st century.  Developed by a team of curators, educators,
writers, designers and scientific consultants, the exhibition is
based on the theme that society and science are inseparable in
modern America--that science has grown into a complex enterprise
interwoven to all aspects of life.

     CARB was established in 1984 by NIST, the University of
Maryland and Montgomery County, Md., as a unique center for
government, academic and industry scientists.

     As a non-regulatory agency of the Commerce Department's
Technology Administration, NIST promotes U.S. economic growth by
working with industry to develop and apply technology,
measurements and standards.

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