How Does a Straw Work?
By: Riley M.
When you drink a soda, do think about how your straw actually works? Now you can find out, it’s not just the suction that pushes the soda up, it’s also all of the atmosphere.

Figure 1.) Colorful Straws
Figure 2.) Straw in a glass of water

How it Works
As your glass sits on the table, millions of air particles push on the water, the glass, and the straw. When your mouth is on one end of the straw and the liquid is covering the other, air particles are pushing on the outside of the straw trying to find a way into it. As the air particles push down, this is called air pressure*, they find no entrance and begin to scatter around the straw. Meanwhile, as you suck suck air out of the out of the straw, it creates a low pressure inside of the straw. As some of the particles come in contact with the liquid, they continue to push down looking for an entrance, causing the water in the glass to move to the place that it can easily get to, the inside of the straw. The reason that the straw is the easiest place to get to is because the inside has become a partial vacuum, or low pressure zone, therefore it has the least amount of pressure that is pushing down on the water, making it the easiest for the water move up the straw.

Figure 3: Diagram of how a straw works

strawwork dia1.jpg strawwork dia2.jpg

Do you know what a vacuum* is? No, not the vacuum cleaner that your mom cleans the carpets with, a vacuum. A vacuum is a space in which all matter has been removed, even air. The Ancient-Greeks were the first people to consider that a space with absolutely nothing in it could exist. Did you know that outer space is thought to be a vacuum? Wouldn’t that be weird to think that when astronauts fly up, they are surrounded by complete nothingness? Some would question the idea that space is a vacuum because it hasn’t been completely proven, but others disagree.

Would a Straw Work in Outer Space?
Now that you know how a straw works on earth, do you think that it would work in space? You would start with your glass, liquid and straw, standing completely still in space. As nothing pushes down on the straw, liquid, or glass, not air or atmospheric pressure*, it would not work. If you were in a space shuttle with a pressurized cabin, the air would put pressure on everything in the cabin. In the end, just sitting in space, a straw wouldn’t work, but in a space shuttle, a straw would work because there is a pressure in the cabin of a space shuttle.


Air pressure/atmospheric pressure: the pressure of the atmosphere pushing down on the earth’s surface and what is on it

Atmosphere: a layer of gas surrounding a planet

Vacuum: a space in which all matter has been removed (even air)


“barometer.” Compton’s by Britannica. Encyclopedia Britannica Online School Edition. Encyclopedia Britannica, Inc., 2012. Web. 25 Sept. 2012.

Brown, Theodore. LeMay, Eugene and Bursten, Bruce. Chemistry: Englewood Cliffs, NJ. Prentice Hall, 1994. Print.

Hewitt, Paul G. Conceptual Physics. San Francisco: Pearson Addison Wesley, 2006. Print.

Hill, Kyle. ‘’Would a Straw Work in Space.’’ Science-Based Life. Science-Based Life. 21 Mar. 2012. Web. 19 Sept. 2012.

Setterfield, Barry. ‘’The Vacuum, Lightspeed, and The Redshift.’’ I Dolphin. June 21 2001. Web. Sept. 23 2012.