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Q & A: Making a vacuum chamber

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Most recent answer: 01/25/2015
So, I was wondering, what would be a possible way to re-create a vacuum in a glass ball or something? I think it might be a cool idea to have a vacuum in a sort of capsule, but I don't think it is possible. Would I need certain materials, or would I need a sample of dark matter or something? I would really like to know. Thanks
- Ian Montgomery (age 11)
Cambridge ON Canada

Good question, Ian. The answer depends on exactly what you mean by "vacuum."

Imagine a cube the size of your fingertip, about one centimeter on each side. On Earth, the "empty" space around you is filled with about 10 quintillion air molecules—that's 10,000,000,000,000,000,000—in every centimeter cube! A perfect vacuum would be totally empty space, with zero atoms or molecules. Even the most advanced scientific laboratories can't produce a perfect vacuum. The best they can do is about 100,000 atoms in each centimeter cube. Outer space is much closer to a perfect vacuum. Out between the stars, there are only about three atoms in each centimeter cube. Between galaxies, there are even fewer. (We're just counting atoms and molecules. If you count other particles, like photons and neutrinos, even intergalactic space isn't so empty.)

You can't make a perfect vacuum in a capsule at home, but you can make a pretty good one—good enough to do some science experiments. You don't even need antimatter. To make your own vacuum chamber, you just need a sturdy container and a pump to suck out the air inside. You could use a  (which you might be able to find at an auto supply store) or even make your own by . You can also buy a vacuum chamber like , made for storing coffee beans or wine (air spoils them over time) for about $20.

There are all kinds of interesting experiments you can do with a vacuum. For example, you can make marshmallows expand and contract, boil water at low temperatures, and inflate an "empty" balloon. Let us know if you try anything.

Rebecca Holmes

PS:  and  are where I got my vacuum numbers.

(published on 01/25/2015)

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