Quote:
Originally posted by stingc
There are no perfect vacua. Your hole would allow air in as well as vapor out. You actually couldn't get it below atmospheric pressure this way. Putting in hot air at atmospheric pressure, and then capping and cooling would give you low pressure, but it isn't very good compared to a vacuum pump.
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A good example of a perfect vacuum on earth is in a barometer. The mercury is heavy enough that at the top of the glass cylinder a perfect vacuum forms.
As for the temperature, the vacuum has no temperature, (no molecules = no temp) however if you were to put an object in the vacuum (technically no longer a vacuum) say a thermometer, that thermometer would be heated by infra red radiation given off by all molecules that have heat. IR radiation can pass through a vacuum ( sun heats earth by IR) and strike an object, converting the IR radiation to the kinetic energy that moves molecules and is in turn: heat.