The Indianapolis times. [volume] (Indianapolis [Ind.]) 1922-1965, 1933-05-31
-Dietz on Science
NINE KINDS OF
WATER KNOWN
TO CHEMISTS
Difference Found Due to
Structure of Oxygen,
Hydrogen.
BY DAVID DIETZ
Seripps Howard Science Editor

Nine kinds of water now are
known to scientists. Perhaps this
fact, better than any other, repre-
sents the rapid strides Of science
and the complex nature of modern
knowledge.
For years, chemists have regard
ed chemically pure water as
standard thing, something always
the same, which could be used as a
basis for various comparisons and
measurements. Thus, for example,
zero on the Centigrade scale was
determined as the freezing point of
water and 100 degrees as the boiling
point Of water
But from now on it will be neces-
sary to specify the variety of water
under consideration.
All nine of them are composed Of
hydrogen and oxygen in the we'll
known tWo-to-one ratio. Insofar
as their chemical reactions are con-
cerned, all the varieties of water are
alike.
However, they differ in physical
qualities. The primary difference is
in their weights. There are also
Slight differences in their boiling
and freezing points and in certain
other characteristics.
Atoms in Two Types
The different kinds of water exist
because there are different kinds of
hydrogen and oxygen. Researches
of the last few years have revealed
that there are two kinds Of hydro
gen atoms. One is twice as heavy
as the other. In addition, there are
three kinds Of oxygen atoms. Atoms
which are alike in every way except
weight are known to scientists as
isOtopes.
Atomaci weights are expressed by
comparison with the lightest of the
oxygen atoms which is rated at six
teen. The other two isotopes Of oXy-
gen have atomic weights of seven
teen and eighteen.
The light atom of hydrogen has
an atomic weight of 1008. The
heavy atom of hydrogen, which the
saVants of the California Institute
of Technology have christened the
"deuton,' has an atomic weight Of
2.016.
Samples Are Prepared
Each molecule of water, as is we'll
known, consists of one atom of oXy-
gen and two atoms of hydrogen.
The lightest possible water would
consist of molecules made up of the
lighter hydrogen and oxygen atoms.
It's molecular weight would be Is
plus 1.008 plus another 1908 or a
total of 1906
The heaviest possible water would
consist of molecules built of the
heavier atoms. It's molecular weight
would be 18 plus 1.016 plus another
1016, or a total of 20032.
Ordinary, samples of water are a
mixture of all the forms Of water.
A number Of laboratories, however,
have been able to prepare samples
in which some one form dominated.
Professor g. N. Lewis of the Uni
versity of California, has succeeded
in preparing samples which con-
tanned about IS per cent of the
heaviest form of water.
Chlorine Is Analysed
The term "isotope" first was sug-
gested by Professor Frederick Soddy
Of Great Britain, in 1918. At that
time, he predicted that investiga-
ton would disclose lead atoms of
two different weights, one resulting
from the radioactive disintegration
of uranium and the other from the
diSintegration of thorium.
In 1919, the construction of an
apparatus known as the mass
speCtrOgraph revealed that neon
consisted of two isotopes. The next
element successfully analysed was
chlorine.
Since then, it has been established
that a majority of the chemical
elements consist of isotopes Tin
has no less than eleven iSOtODeS.