South Bend news-times. (South Bend, Ind.) 1913-1938, 1917-02-19

VIII OccdSl Onally see the doctors
pulling one another around by the
ears over the definitions OF these
subjects. In short. a good general
rule to bear in mind is that when
ever you find anything defined as
that which does so and So" you
may safely conclude that the that
which" is something which respect
fully but firmly declines to be
pinned and labelled.
The Amount of Work Done Gives
Fair Measure of Energy
Expended.
on the other hand, you must not
suppose that barring the difficulty
of telling what it is except by talk
ing of what it does, there is any
thing incomprehensiole about en-
ergy. The amount of work done, or
of effect produced, gives a fair meas
ure of the energy expended. If you
think of energy as the cause of all
physical. chemical, electrical or 9TH
er forms Of activity you will have a
workaday conception of il. Science
suppOses that the universe contains
a certain sum of energy, which can
not be increased or diminished I'M
less something outside Of, or super
Tor to, the universe should interfere.
That something would necessarily be
a supernatural power. capable of
making or changing nature at it's
will-in a word, God
There are people who think that
energy is God. l have never cared
10 try to believe that. But let us
descend again to the level of science
and take up your question in another
way. Heat has been defined as a
form of enersy, but il is, rather, an
effect of energy. Heat consists in a
vibratory motion of the molecules
Of a substance. This motion can be
transferred from one substance TO
another. A hot iron will set a piece
of wood on fire. The burning of
the wood is the result of violent
vibration OF its molecules, which
arc thus thrown out of cohesion,
and, according to their nature,
shape themselves anew, some into
ashes, some into smoke. and some
into gas, or vapor.
The flame is the result of addi-
tional molecular vibration, disinteg-
rating carbon and other chemical
elements set free from the wood and
turning them into the gaseous con-
dition. or rendering those that are
already gaseous luminescent, or
light-giving Energy, then. may be
said TO create heat, but heat cannot
create energy; il can only hand it
along. or call it into operation.
There May BE Light Without Heat,
But IL Is Always Energy
That Creates It.
Energy is the most protean thing
imaginable. II has endless forms
and guises. When the temperature
becomes great enough the thermal
energy" or that which produces
heat, changes into light energy"
or that which produces luminosity.
There may be light without percep-
tible heat, as in the frefy's lantern.
or in phcsphorescence, but it is al
ways energy that creates it.
If energy were not so changeable
in its forms the world could not ex-
list as we know it. and we could not
live The food that we eat is full
of energy which is transformed into
the vital forces. Streams of energy
are continually entering and leav-
ing our bodies. Nothing of il is ever
lost Change is ceaseless and uni
versal but in the sum total there is
neither loss nor gain.
The books usually speak of energy
in two forms-potential energy
and kinetic energy. BY potential
energy is meant energy not in mo-
ton. or not doing work. Kinetic en-
ergy is energy in motion, or doing
work. If you suspend a stone by a
string from the ceiling. the stone
possesses potential energy in proper
ton 10 its weight and the distance
from the floor.
If YOU cut the string, the energy
in the stone at once change TO the
kinetic form as the stone falls. But
a hot body also contains kinetic en-
ergv. because Of the vibration OF its
molecules. and this form OF kinetic
energy may be derived from the
other by causing the moving body TO
strike another body. thereby ar
resting its motion as a whole Then
the energy that kept the body NOV
ing will give rise 10 energy acting
upon the molecules by setting them
into the vibratory movement called
heat