– Dr. John A. Pojman will travel to NASA's Marshall
Space Flight Center in Huntsville, Ala., Saturday, April 2, to help Cmdr. Leroy
Chiao perform Pojman's experiment on the International Space Station.
will mark NASA's seventh run of the Miscible Fluids in Microgravity (MFMG) experiment,
designed by Pojman, a professor in the Department of Chemistry and Biochemistry
at The University of Southern Mississippi.
The MFMG experiment
will test how miscible fluids - those that completely dissolve in each other -
interact without the interference of gravity. Pojman will be able to talk to Chiao
in real time, watch him perform the experiment and offer advice.
fluids, like oil and water, exhibit something called "interfacial tension"
because of the different ways that each type of molecule pulls on another. "This
interfacial (surface) tension is what allows a water skeeter to walk on water,"
The experiment will test a timeworn but
unsupported theory. "One hundred years ago, a scientist named Korteweg predicted
that miscible fluids could act like immiscible fluids until they had diffused
and become uniform," Pojman said.
has been much theory and some provocative experiments during the intervening century,
no definitive experiments have been performed. This simple experiment will be
a step toward a complete test of Korteweg's hypothesis."
a stream of one immiscible fluid is injected into another in weightlessness, the
stream will break into drops - a phenomenon called the Rayleigh-Tomotika instability.
Pojman said his test will determine if the same breakup occurs with two miscible
fluids by injecting honey into water and observing if the honey stream breaks
"Because the honey is denser than water,"
he said, "the stream sinks in the water when we try to do the experiment
However, the experiment does have some down-to-earth
implications, Pojman said. "The models used to simulate the experiment provide
information on the fundamental interactions between molecules."
the first runs were performed in March 2004, Pojman's collaborators, Vitaly Volpert
in France and Nick Bessonov in Russia, have performed computer simulations based
on those early results. "We determined that we need to let the experiment
run longer," said Pojman. "We changed the procedures, and NASA accommodated
This will be the third crewmember to perform
Pojman's experiment. "I briefed Cmdr. Chiao from my kitchen in New Orleans
in December. The call was routed from the Space Station to a satellite to White
Sands Missile Range to Houston and then to my home. It was a thrill for my three-year-old
son and my wife to be able to listen to the conversation," Pojman said.
more information, contact Pojman at (504) 296-7224.