92
Reference
idea to invent the hydraulic press. Pascal’s principle is often
used in devices that multiply an applied force and transmit it
to a point of application. Examples include the hydraulic jack,
and the pneumatic cylinder.
Gas Laws
The actions of gases under varying conditions of temperature,
pressure, and volume can be described and predicted by a set
of equations, or gas Laws. These Laws were determined by
measurements of actual gases and are valid for all substances
in a gaseous state.
Measurements on gases were first published by Robert Boyle
in 1660. He figured out that if an enclosed amount of gas is
compressed until it is half its original volume while the
temperature is kept constant, the pressure will be doubled.
Quantitatively, Boyle’s Law is: PV = Constant, where the
value of the constant depends on the temperature and the
amount of gas present.
Relationships between the temperature of the gas and its
volume while keeping the pressure unchanged were studied
by Jacques Charles. He saw a steady increase in the volume as
the temperature went up, finding that for every degree Celsius
rise in temperature, the gas volume increase by 1/273 of its
volume at zero degrees C.
Charles’s Law and Kelvin Temperature
Charles’s observations led to the absolute (Kelvin)
temperature scale, since the gas, according to the equation,
would have zero volume at -273 degrees C. The absolute
temperature scale was defined by Kelvin so that absolute
temperature equals negative 273 degrees C and each absolute
degree is the same size as a Celsius degree. The modern value
for absolute zero is -273.15 degrees C. This temperature scale
allows Charles’s Law to be written V/T = Constant, where V
Содержание sprint iq
Страница 1: ...Owner s Guide...
Страница 24: ...22 Quick Start...
Страница 50: ...48 Menus...
Страница 116: ...114 Reference 45 pounds per square inch pressure then increase at a rate of 10 pounds per square inch every second...