vacuum (an empty space, void) noun use of neuter of vacuus (empty)
related to vacare (be empty). It is one of the few words in the
English language to have the letter combination of uu.
When you evacuate the V-Bag it becomes rock hard and keeps its
shape exactly unchanged. The reason is the heavy force that the
pressure differential between the empty inner side and the
atmospheric outside act on the bag.
The Power of Vacuum was first demonstrated by German scientist
Otto von Guerickein in 1650 in the German city Magdeburg. The
copper hemispheres were sealed with fat and evacuated by the pump
that von Guericke wanted to demonstrate. The hemispheres could not
be pulled apart by teams of horses.
To day the original hemispheres are exhibited in Deutsches museum
A vacuum is a volume of space that is essentially empty of
matter, such that its gaseous pressure is much less than
atmospheric pressure. The word comes from the Latin term for
"empty," but in reality, no volume of space can ever be perfectly
empty. A perfect vacuum with a gaseous pressure of absolute zero is
a philosophical concept that is never observed in practice.
Physicists often discuss ideal test results that would occur in a
perfect vacuum, which they simply call "vacuum" or "free space" in
this context, and use the term partial vacuum to refer to real
vacuum. The Latin term in vacuo is also used to describe an object
as being in what would otherwise be a vacuum.
The quality of a vacuum refers to how closely it approaches a
perfect vacuum. The residual gas pressure is the primary indicator
of quality, and is most commonly measured in units called torr,
even in metric contexts. Lower pressures indicate higher quality,
although other variables must also be taken into account. Quantum
theory sets limits for the best possible quality of vacuum,
predicting that no volume of space can be perfectly empty. Outer
space is a natural high quality vacuum, mostly of much higher
quality than can be created artificially with current technology.
Low quality artificial vacuums have been used for suction for many
Vacuum has been a frequent topic of philosophical debate since
Ancient Greek times, but was not studied empirically until the 17th
century. Evangelista Torricelli produced the first laboratory
vacuum in 1643, and other experimental techniques were developed as
a result of his theories of atmospheric pressure. A torricellian
vacuum is created by filling a tall glass container closed at one
end with mercury and then inverting the container into a bowl to
contain the mercury.
Vacuum became a valuable industrial tool in the 20th century with
the introduction of incandescent light bulbs and vacuum tubes, and
a wide array of vacuum technology has since become available. The
recent development of human spaceflight has raised interest in the
impact of vacuum on human health, and on life forms in general.