Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-10-19
STRIKING PARALLELS
That Can Be Drawn Between Electric
ity and Everyday Water.
HOW THEY ARE MADE TO Do WORK.
Each Has Its Dam and Its Flood, Its Eric.
tion and Its Leakage.
INSTRUCTION PUT In A NOVEL WAY
WRITTEN FOR THE prsPArcH.l

Energy is a condition of things having
the capacity to perform work, and it, like
matter, is indestructible. 1t can be trans
formed from one condition of things to
another, and in this way change its char
acter. But energy cannot be truly lost or
created through any human agency. Our
greatest and almost only source of energy is
the Sun. Its energy is transmitted to the
earth in the shape of light and heat, and
from this condition it is transformed into
countless other forms, ever ready to slave
for mankind in various capacities.
The heat of the sun will evaporate water
and form the clouds. The heat energy of
the sun has thus been transformed into
energy of position; that is to say, clouds
represent energy by virtue of their position
in that the earth and clouds have a strong
attraction for each other, and when they
come together, in the shape of rain. the rain
water will reproduce the exact amount of
energy expended in vaporising it. Again,
the heat energy of the sun can be trans
formed in a most wondrous way and enter
into the chemical construction of wood and
| coal, and then, in a minute or in an hour,
this solar energy, that had been accumulat-
ing for years and perhaps centuries. can
again be transformed into heat, as may be
daily seen in any wood or coal fire. The
energy taken out is in every case equal to
the energy absorbed.
ENERGY THAT IS LOST.
When we speak of lost energy we mean
that some of the energy has escaped without
doing useful work. For example, let us
follow energy through various transforma-
| or,1 rzo%h r
| with the solar heat we next find it in coal or
wood, and, this being burned, it is again
transformed into heat, having a more useful
form than solar heat. This artificial heat
can then be made to expand water. The
| energy here is due to the strained condition
OF the water PARTICLES which we call steam.
The steam can then drive an engine and
thus give us the energy of a moving mass,
and with this we can drive the armature of
a dynamo and once more transform the
energy, this time into the condition known
| as electricity.
| But the electric energy that we now have
is very, very small proportion of the solar
energy that we started with. Without going
| into figures it will at once be evident that a
| large proportion of the heat energy went up
the chimney, while steam was being gener-
ated; another large proportion was radiated
from the boiler into the air, and certainly
no small amount was trans ormed from the
energy of moving mass into heat, due to
the friction of the machinery used. In such
cases the energy is said to be lost, but as a
matter o! fact, it is simply switched of, so
to speak, and left behind. 1t is only lost
as FAR as dollars and cents are concerned.
Although the exact nature of electricity is
but imperfectly understood, it is very GER
tain, as we have just seen, that he electric
current represents form of energy; that is,
condition of things capable of performing
work, and that it can be generated from
other forms of energy and again transformed
at will.
AN INSTRUCTIVE COMPARISON.
Such expressions as electric current"
and Electric fluid" are often heard, and,
although these are merely names given to
an imperfectly understood condition of
things, yet it must be admitted that there is
a striking likeness between some of the
characteristics of an electric current" and
the flow OF water through pipes. Both can
have reservoirs, dams, conductors, quantity,
pressure and drop in the pressure along the
pipe or wire, as the case may be. Both can
leak out through imperfections in their re-
spective conductors, and electricity, as we'll
as water, can. by the giving way of the
dam-if I may be allowed the expression
be the cause of disaster as great as that of
the JohnstowD food.
A dynamo, so long as its armature is kent
in motion, is a reservoir OF electricity, and
in it there is generated both pressure in
volts and quantity in amperes, according to
the construction of the dynamo. The
product of the pressure into the quantity
gives the energy in watts and TAG watts are
equivalent to one horse power. With water
this energy is represented BY the product of
its weight in pounds and height in feet
The product is called so many foot pounds,
and 5000 ioot-pounds per minute is equiva-
lent to one horse power. Here it must be
understood that $4,000 pounds raised one
foot represents the same amount of energy
as one pound raised 80, 900 feet. With cleo
tricity, rs with water, we must have closed
circuit to generate power. Water to gen.
crate power must fall or flow, and to fall it
must rise. In other words, water comes
from the clouds, passes over the falls, and
in SO doing generates power; then it flows
into the ocean, and is finally drawn by
evaporation back into the clouds. thus
closing the circuit. And so it is with cleo
tricity-there must be a closed circuit to |
generate power.
WORK FROM THE CURRENT.
A closed electric circuit is obtained when
the two wires or poles OF a dynamo are |
brought in contact. If there is resistance
in the circuit, such as arc or incandescent
lamps, the current will do useful work lust
as flow OF water will when it overcomes
the interposed resistance of a water wheel.
If, however, there is no useful work to be
done in the electric circuit, the electric en-
ergy is all converted into heat due to fric-
tion along the line. With water it is the
same. Niagara Falls might be made to do
useful work, but as it is, its energy is all
transformed into heat, and so the tempera-
ture of the water below the falls is greater
than it is above. If there is very little re-
sistance in the electric circuit-the resist
ance being what I would call the dam-and
if the reservoir or dynamo is great enough,
a tremendous flow of current will
be the result So it is again with water.
If the dam or resistance, keeping the water
back is removed, there will be a rush of
water corresponding to the capacity of the
and resisted only by the friction
Of the channel.
An electric circuit having very little re-
sistance is called a short circuit. The like
ness between an electric current and a flow
Of water can again be found with regard to
the ''drop" in the pressure along the wire or
pipe. A pipe having flow OF water in it