How does straw work

Since the atmosphere is also pushing down on the liquid in the straw, the liquid rises, just until the force of the atmosphere on the liquid inside the straw exactly balances the force of the atmosphere inside the glass.

That happens when the levels are even. So, why can you use a straw to get the liquid up into your mouth, higher than the level in the glass? When you inhale through the straw, you take the atmosphere out of the straw it goes into your lungs. Now the atmosphere is pushing down on the liquid in the glass, with noting the balance it inside the straw, so the liquid rises…into your mouth!

Scientists deal with this problem all the time. Here are a few experiments you can try to see the atmosphere! Drink something from it to be sure that it works. Now, make a small hole in it make sure the hole is large enough to see. Make sure the hole is above the level of the liquid in the glass. Does the straw still work? What happens if you cover the hole with your finger and then try to drink? Give Now ».

Noon Edition. Home Archives About Contact. How Do Drinking Straws Work? By Don Ulin Posted November 24, Media Player Error Update your browser or Flash plugin.

Decreasing Air Pressure With the straw just sitting in the glass, the pressure on the surface of the tea is the same all over, including on the little bit of surface inside the straw. Why Do Straws Work? With the straw just sitting in the glass, the pressure on the surface of the tea is the same all over, including on the little bit of surface inside the straw. When you suck the air out of the straw, you decrease the pressure inside the straw, allowing the higher pressure on the rest of the surface to push the tea up the straw and into your mouth.

Because it is really the atmosphere that is doing the pushing, the atmospheric pressure limits how high water will go up a straw. If you formed a perfect vacuum within the straw, the pressure outside of the straw at sea level would be enough to push water to a total height of about