Ask A Scientist© Chemistry Archive

   > >    name         Cassy
 > >    status       student
 > >    age          13

 > >    Question -   How did scientists reach absolute zero. What types of
 > > things did they use and how was it acomplished. How long did it take and
 > > how useful is it.

Dear Cassy,
The Third Law of Thermodynamics states that it is
impossible for a real experimental system to be brought
down to a temperature of absolute zero. However,
one can get really, really close, down to microkelvins
of degrees above this temperature.

A variety of methods can be used to bring systems down to
really low temperatures. I believe that the lowest temperatures
achieved were by using laser beams and magnetic fields to
push around a small number of cesium atoms inside a
"magnetic bottle," and that this work was done at the NIST
labs in Colorado. You might try searching the NIST web site
at http://www.nist.gov.
Best regards,
Prof. Topper
The Cooper Union
New York, NY
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Absolute zero has never been attained.  Experimenters are able to get
closer and closer as technical advances are made, but never to actual
absolute zero.

In fact, the third law of thermodynamics states that absolute zero is
unattainable.


                Richard Barrans Jr., Ph.D.
                Chemical Separations Group
                Chemistry Division CHM/200
                Argonne National Laboratory
                9700 South Cass Avenue
                Argonne, IL 60439
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