May 14, 2007 With meteorologists concerned about a possible
worldwide intensification of tornado activity, scientists in
Germany are proposing a new approach to studying formation of
twisters, which pack Earth's most violent winds. It involves
forming microtornadoes under millimeter-scale crystalline
"igloos," according to a report by Andrei P. Sommer scheduled
for publication in the June 6 edition of ACS' Crystal Growth &
Design, a bi-monthly journal. In the report, Sommer describes
evaporating tiny drops of water laced with polystyrene
nanospheres to form the transparent igloos. The drops consisted
of 15-microliters of liquid -- 15 millionths of a liter -- and
formed the translucent "igloos" after being deposited on a
surface under an evaporation chamber. As the drops evaporated
(taking 191 hours, a record for such experiments), Sommer
observed patterns formed by swirling micro-vortexes that
appeared similar to those formed by tornadoes under real-world
conditions. Because the conditions favoring the format