Evening star., 1952-01-30
Sparks Struck in Water
Intriguing to Physicists
Flosh Of Fire Is Recorded
When Steel Hits Surfuce
BY Thomos r. Henry

=
By Thomos R. Henry
Physicists at The Naval Ordnance Lab
oratory here are striking sparks from
water.
They have discovered q hitherto un-
known physical phenomenon which
gives the illusion. at least. Of burning
water" It Is observed when steel balls
are shot vertically downward into water
at speeds Of about 1000 feet second.
Almost at the instant the ball hits
the water surface there is . flash Of
fire.
The phenomenon has Just been re-
ported by Drs. J. NJ McMillen, n. Z.
Kramer and D. E. Allmand OF the lab
oratory staff. Several explanations have
been offered. none Of which is considered
entirely satisfactory.
Evidence indicates clearly, the phys
icists say. that the light Is emitted close
to the surface Of the. water, certainly
within one sphere diameter. The fash
is observed visually In q darkened room
and can be photographed with an open
shutter camera. It has been possible to
obtain simultaneous records Of the Inn
pact flash and Of the shock wave set
up in the water when the missiles strike.
One theory is that the compression
produced by the impact Is suficient to
heat the water to the point where it be-
comes luminous. but actually higher
pressure Is required than 1t Is possible to
produce. Another theory is that the
individual water molecules acquire the
same speed as the missile at impact. This
would give them temperature Of 2.000
degrees centigrade, probably sufficient
to make them luminous. .
Although some OF the luminosity II
observed apparently above the surface.
the greater part Of 1t seems to be with
In the water. which seems to be burn.
ing. It is Of extremely short duration.
like spark struck from flint.
Scientific Curiosity Thus Far.
At present. it Is pointed out In the
report. the observation can be con-
sidered only scientific curiosity, but
search for an adequate explanation may
open new fields in physics.
The phenomenon is not observed at
lesser speeds than 1000 feet second
and probably could not take place at
lower speeds.
A revolutionary development In rain.
making has been announced by the
Australian Commonwealth Scientific and
Research Organization.
1t consists Of spraying low clouds with
water. The technique was described by
DR.. E. G. Bowen, physicist member Of
the organization, at California Institute
Of Technology.
In this country rainmakers have con-
centrated on seeding clouds with dry
Ice or silver iodide and have met with
considerable success. BY using only
water, however the Australians have
started rain falling in Is to 20 minutes
and their experiments indicate single
ton of water should yield at least Q
million tons Of rain. s
The experiments have been on low
hanging clouds. In Australia so per
cent Of the country's rain comes from
low clouds. Silver iodide and dry ice
proved to be more effective than water
in high cumulus clouds, where freezing
occurs. In the low clouds the effect
of the sprayed water was 10 Introduce
droplets larger than those already sus-
pended in the cloud. The small drops
Of water attach themselves to the large
ones, which soon become so heavy they
fall to earth. sE705
More Research Needed.
The Australians, DR.. Bowen said, will
not go in for large scale rainmaking
until they are sure 1t Is q safe pro-
cedure. This means about two more
years of basic research. ,...'.
Down Under" physicists, he an
nounced, also have concentrated on
radio waves received on earth from the
moon and on radio echoes from the
moons surface. The first experiments
have enabled them to estimate ac-
curately the moons temperature. It
ranged from a high Of 158 r. to q low
Of -1454, with a mean temperature Of
-86. Essentially similar results have
been obtained by California Tech scien-
lists. using an entirely different pro-
cedure.
In less than a year, it was an
nounced, the researchers have hit the
moon with radio waves and received
echoes about IS times. Signals took
two and a half seconds to make the
round trip Of 100000 miles, which
means that they went at about the speed
Of light.
The experiments leave some doubt,
DR.. Bowen said. about the feasibility
Of using the moon to reflect messages.
The echoes from the moon In nearly
all cases were extremely blurred.