Vacuum

Vacuum is space that is empty of matter. The word stems from the Latin adjective vacuus for "empty" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a perfect vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. The Latin term in vacuo is used to describe an object as being in what would otherwise be a vacuum.

The quality of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. Much higher-quality vacuums are possible. Ultra-high vacuum chambers, common in chemistry, physics, and engineering, operate below one trillionth (10−12) of atmospheric pressure (100 nPa), and can reach around 100 particles/cm3. Outer space is an even higher-quality vacuum, with the equivalent of just a few hydrogen atoms per cubic meter on average. However, even if every single atom and particle could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, and other phenomena in quantum physics. In modern particle physics, the vacuum state is considered as the ground state of matter.

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 with mercury a tall glass container closed at one end 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.

Read more about Vacuum:  Etymology, Electromagnetism, Quantum Mechanics, Outer Space, Historical Interpretation, Measurement, Uses, Effects On Humans and Animals, Examples

Other articles related to "vacuum":

Vacuum - Examples
... cm3 Standard atmosphere, for comparison 101.325 kPa 66 ... nm 2.5×1019 Vacuum cleaner approximately 80 kPa 70 ... nm 1019 liquid ring vacuum pump ...
John Hennon
... Duhem, in Le système du monde, isolates Hennon's account of the vacuum and a plurality of worlds ... Hennon believed that nature abhors a vacuum and therefore no natural void was possible, though God could create one ... that a sealed vase of water will break upon freezing because nature abhors a vacuum ...
J. Schmalz Gmb H
... blades to transport equipment and finally to vacuum components, vacuum handling systems, vacuum gripping and clamping systems ... The company is in the sector of vacuum clamping technology and one of the suppliers of vacuum technology in the fields of automation and handling ...
J. Schmalz Gmb H - Products
... Schmalz’s vacuum technology is utilized in production processes that require workpieces to be moved, ergonomically transported, or secured ... Vacuum components Vacuum components help a wide variety of users and industries to perform automation and handling tasks ... The range of products includes vacuum suction pads, vacuum generators, mounting elements and system monitors ...
RMA Tube Designation
... used a descriptive nomenclature system for industrial, transmitting, and special-purpose vacuum tubes ... and inductive output tubes) L-- Vacuum capacitors N-- Crystal rectifiers (This designation lived on as the "N" in the EIA/JEDEC EIA-370 solid state device numbers standard, like 2N2222) P-- Photosensitive types (ph ...

Famous quotes containing the word vacuum:

    When a daughter tries suicide
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    Anne Sexton (1928–1974)

    Teenagers who are never required to vacuum are living in one.
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