How do you make a vacuum?

Answer 1

As i did a practical regarding this i found that it is quite easy to create vacuum(about 95%) inside the hollow tube(50 cm length,30 mm Di) by just placing it above the boiling water surface.just let the steam get inside.close the open end and let the steam get condensed.you will get vacuum inside the tube.As steam replaces the air.Before closing the free end place a layer of some moisture absorbent over inside of covering cap.

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1 way is to light a match in a sealed glass. The fire uses up all the oxygen, thus creating a vacuum in the glass.

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Actually lighting a match inside glass will not create a vacuum. It will lower the pressure inside the container however a bit. The reason it does not create a vacuum is that when the oxygen is "used up" the oxygen molecules do not leave the container. They Chemically react with other molecules to form fewer molecules. This lowers pressure because of how gasses behave. The presssure of a gas in a sealed container is proportional to the number of gas molecules (I will calll this number n). Combustion reduces the number of gas molecules and reduces the pressure. Of course if the gas is heated enough in the process the effect will be negated, but a match will probably burn itself out before that happens in a reasonably sealed container.

In the laboratory by pumping the air out of a container to begin with and then using clever tricks to remove the last traces of air.

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(im not any of the other people) Actually, the law of conservation of matter in physics class says that matter cannot be destroyed or created, only changed, so i don't believe a match could create a vacuum because when you light a match it would change the oxygen molecules into some other elements found in smoke and the other particles released by the chemical reaction.

To really create a vacuum, you would need a vacuum pump to pump out all the gases in the container.

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(I am yet another contributor) Let me address each piece of information in here. First, to the original question, there are a number of different ways to create a vacuum. It depends on several factors, including what kind of gas you're trying to evacuate and how big the chamber is. Wikipedia has a very thorough article on the matter under 'Vacuum'. One way is to expand an area, thus reducing the pressure. You then cut that area in half with another mechanism, and then expand that area. Just repeat and you'll have a pretty good vacuum at the end. There is no known way to create a perfect vacuum. Even space has gas molecules zipping around.

About the original answer:

Yes, the fire will use up oxygen, but you must remember that oxygen might not be the gas they're dealing with. Or, if they're dealing with more than one type of gas (the atmosphere), you'd need some sort of reaction that uses up all kinds of different gases. On top of that, combustion reactions release CO2. For every molecule of oxygen that you use up, 1 CO2 molecule will be released. Not to mention the other chemicals that are burning in the match.

Vacuum: A space that is completely lacking all matter.

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A vacuum can be created by removing air from a space using a vacuum pump or by reducing the pressure using a fast flow of fluid, as in Bernoulli's principle,principle that relates pressure, velocity, and height for a nonviscous fluid with steady flow.