How Drinking Straws Work
submitted by: Emery B
Last updated: 10/4/11

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Straws are used every day by people, but we don’t think much about how they work, in fact we probably don’t think about the way straws work at all anyway! But they are an important tool to have, and can be very useful when the rare situation calls for a straw.

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Straws work very fast, so keep in mind that all this happens in less than a second.
First, you have a straw in liquid. The straw is full of air.
Then you put your mouth on the end of the straw, and suck.
This sucks all the air out of the straw, creating a vacuum.
The air around the straw wants to be where there isn’t air, and since no air exists in the straw, the air tries to get in.
But that won’t happen so easily, since water is blocking the other end of the straw. The air pushes on the water, eventually pushing the water up into your mouth.

Ever tried to use a straw in a thick liquid, and the straw went flat?
That's because the air can't push the thick liquid up the straw, so it pushes on the rest of the straw. The straw is weaker than the air so it crushes the straw.

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Suction is also a key part in straws. Suction is the flow of liquid into a partial vacuum. In this case suction is the flow of water (Or whatever you happen to be drinking) into and up the vacuum, which is our straw.

Glossary:
Vacuum: A place without air.
Suction: The flow of fluid into a vacuum, or area of low pressure.

Sources

Macaulay, David (The way things work) Boston: Houghton Mifflin, 1998. Print

"Suction" Wikipedia, Wikipedia the free encyclopedia.
Wikipedia 2011.Web. Sept. 2011
"vacuum" Encyclopedia Britannica, Encyclopedia Britannica online school edition.
Encyclopedia Britannica 2011. Web. Sept 2011