Energy, Potential, or Static Energy.
The capacity for doing work in a system due to advantage of position or
other cause, such as the stress of a spring. A pound weight supported
ten feet above a plane has ten foot lbs. of potential energy of position
referred to that plane. A given weight of an elementary substance
represents potential chemical energy, which will be liberated as actual
energy in its combination with some other element for which it has an
affinity. Thus a ton of coal represents a quantity of potential chemical
energy which appears in the kinetic form of thermal energy when the coal
is burning in a furnace. A charged Leyden jar represents a source of
potential electric energy, which becomes kinetic heat energy as the same
is discharged.
Energy, Thermal.
A form of kinetic molecular energy due to the molecular motion of bodies
caused by heat.
Entropy.
Non-available energy. As energy may in some way or other be generally
reduced to heat, it will be found that the equalizing of temperature,
actual and potential, in a system, while it leaves the total energy
unchanged, makes it all unavailable, because all work represents a fall
in degree of energy or a fall in temperature. But in a system such as
described no such fall could occur, therefore no work could be done. The
universe is obviously tending in that direction. On the earth the
exhaustion of coal is in the direction of degradation of its high
potential energy, so that the entropy of the universe tends to zero.
(See Energy, Degradation of.)
[Transcriber's note: Entropy (disorder) INCREASES, while AVAILABLE
ENERGY tends to zero.]
Entropy, Electric.
Clerk Maxwell thought it possible to recognize in the Peltier effect, q.
v., a change in entropy, a gain or loss according to whether the
thermo-electric junction was heated or cooled. This is termed Electric
Entropy. (See Energy, Degradation of.)