What is vacuum?

Answer 1

A vacuum is a volume of space that is essentially empty of matter, so that gaseous pressure is much less than standard atmospheric pressure.

Answer 2

A Vacuum Is A Space Devoid Of Air, Though Not Necessarily Empty. If You Take For Example Anything That Has Been Vacuum Packed For Freshness Or Otherwise. In This Case The Air Has Been Removed In A Packing Plant Prior To The Packaging Being Sealed.
Have A Gooday And A Bonza Christmas Mate!

Answer 3

Although the Latin word vacuum means "empty", the object of vacuum techniques is far from being spaces without matter. At the lowest pressures which can be obtained by modern pumping methods there are still hundreds of mole­cules in each cm3 of evacuated space.

According to the definition of the American Vacuum Society (1958) the term "vacuum" refers to a given space filled with gas at pressures below atmospheric, i.e. having a density of molecules less than about 2.5 x 1019 molecules/cm3.

The general term "vacuum" Includes nowadays about 19 orders of magnitude of pressures (or densities) below that corresponding to the standard atmosphere. The lower limit of the range is continuously decreasing, as the vacuum techno­logy improves its pumping and measuring techniques.

Answer 4

A vacuum is a machine that pulls air inwards at a high rate. If you were to place something flat against the entrance of the vacuum the suction power wouild be so great that the flat thing would "stick" to the opening.

The most common kind of vacuum in the United States would be the household machine we use to suck air and debris from our carpet into a container (or bag).

Essentially a "vaccum effect" would be the same effect that I mentioned above. A pulling of air inward so hard that suction occurs.

Answer 5

A vacuum is a space with no or very little gas pressure. VAN ALLEN, JAMES A. James A. Van Allen was an American physicist who discovered doughnut-shaped belts of radiation that circle the Earth (the van Allen Belts).

Any pressure less than atmospheric pressure
or
Vacuum is created through use of a vacuum pump or aspirator pump, to facilitate specific biological preparations, such as inclusions or disinfection of material for in vitro culture, etc.

Answer 6

A vacuum is a volume of space that is essentially empty of matter, so that gaseous pressure is much less than standard atmospheric pressure. The root of the word vacuum is the Latin adjective vacuus which means "empty," but space can never be perfectly empty. A perfect vacuum with a gaseous pressure of absolute zero is a philosophical concept that is never observed in practice, not least because quantum theory predicts that no volume of space is perfectly empty in this way. Physicists often use the term "vacuum" slightly differently. They 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 the imperfect vacua realized in practice.

The quality of a vacuum is measured by how closely it approaches a perfect vacuum. The residual gas pressure is the primary indicator of quality, and it is most commonly measured in units of torr, even in metric contexts. Lower pressures indicate higher quality, although other variables must also be taken into account. Quantum mechanics sets limits on the best possible quality of vacuum. Outer space is a natural high quality vacuum, mostly of much higher quality than what can be created artificially with current technology. Low quality artificial vacuums have been used for suction for millennia.

Vacuum has been a common topic of philosophical debate since Ancient Greek times, but it was not studied empirically until the 17th century. Experimental techniques were developed following Evangelista Torricelli's theories of atmospheric pressure. Vacuum became a valuable industrial tool in the 20th century with the introduction of the light bulb and vacuum tube, 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 life forms in general.

http://en.wikipedia.org/wiki/Vacuum

Answer 7

Vacuum, theoretically, space without matter in it. A perfect vacuum has never been obtained; the best man-made vacuums contain less than 100,000 gas molecules per cc, compared to about 30 billion billion (30×1018) molecules for air at sea level. The most nearly perfect vacuum exists in intergalactic space, where it is estimated that on the average there is less than one molecule per cubic meter. In ancient times the belief that “nature abhors a vacuum” was held widely and persisted without serious question until the late 16th and early 17th cent., when the experimental observations of Galileo and the Italian physicist Evangelista Torricelli demonstrated its essential fallacy. Torricelli obtained a nearly perfect vacuum (Torricellian vacuum) in his mercury barometer. A common but incorrect belief is that a vacuum causes “suction.” Actually the apparent suction caused by a vacuum is the pressure of the atmosphere tending to rush in and fill the unoccupied space. There are various methods for producing a vacuum, and several different kinds of vacuum pumps have been devised for removing the molecules of gas or vapor from a confined space. In the rotary oil-sealed pump a rotor turning in a cylinder allows gas to enter through an inlet valve from a space to be evacuated and then pushes it through an outlet valve into the atmosphere. In the oil or mercury diffusion pump, gas enters the pump through an inlet and is then swept toward an outlet by heavy, fast-moving oil or mercury vapor molecules. The outlet is connected to a rotary pump that expels the gas into the atmosphere. A cryogenic pump removes gas from a container by condensing the gas molecules on an extremely cold surface in the container. An ion pump consists of a chamber containing a source of electrons that are used to bombard gas molecules from a container to be evacuated. Collisions between the electrons and gas molecules ionize the molecules, causing them to be drawn to, and held by, a collector in the pump. The first vacuum pump was invented by the German physicist Otto von Guerricke in 1650. There are many practical applications of vacuums in industry and scientific research, e.g., in vacuum distillation, vacuum processing of food, in devices such as the vacuum tube, vacuum bottle, and barometer, and in research machines..

Answer 8

Vacuum is a medium without a medium. Without any matter like gas, etc between it at all! Vacuum cleaner works on the same principle.

Answer 9

when we dragout everything from a particular volume, the above said volume is said to be vacuum. But 100% vacuum is not possible. Everything outside the volume will be trying to go into it.

Answer 10

A vacuum is an empty space.

Some scientists say the temperature of absolute zero is found in vacuums, but it hasn't gotten that cold.