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How to use the vacuum? | Physics
How to use the vacuum? Although air is everywhere around us, we can not see, smell or taste
Although air is everywhere around us, we can not see, smell or taste. We can feel how it moves when the wind blows. Without air our planet would be without water, without the empty desert creatures. Air is a mixture of gases, mainly nitrogen and oxygen. Most people think that the vacuum in the place where no matter where the place is not absolutely nothing.
However, in the opinion of scientists, it is impossible. They believe that there is no space in which no there is some substance, some molecules of gas or a particle of dust.
The vacuum is actually a space in which there is a very small amount of matter. Space is a vacuum, although it contains some dust and gaseous particles. In a good vacuum is almost no air, dust and other particulate matter. But here is the emphasis on the word, almost.
One of the easiest ways of getting the vacuum pumping air from the container into which it is necessary to create a vacuum. very efficient vacuum pumps, which can create a good air-free space, which are used in the industry. For example, a vacuum pump is used in the manufacture of electric bulbs. If air remains in the bulb, in a split second to oxygen combustion caused žaruljina fibers.
The bulbs modern manufacturing almost all the air pump removed. It is also in production of vacuum tubes for radio and television receivers. just before closing, the air is removed to the greatest extent possible.
probably the most famous use of vacuum in the thermos bottle. Thermos flasks have double walls and vacuum is created between the walls. In thermos vacuum bottle is placed between the outer and inner walls of the container. The bottled beverage stays hot or cold because the heat is hard to pass a vacuum so hot beverage retains heat and it can not reach out to a cold beverage.
vacuum is still used in the evacuation of food or clothing, special bags from which displaces the air ..