There is more to drinking out of a straw than meets the eye! Most people think that when they suck on a straw, the liquid goes right into their mouth. However, there is science behind it. With just some understanding of physics and air pressure, we will explain how does a straw works ! All you need is a straw and a glass of water
WHAT IS AIR PRESSURE
Before we can explain how a straw works, we must first comprehend what air pressure is. The air around us has weight, and it presses against everything it comes into contact with.. The amount of force that these air molecules put on a surface is called air pressure or atmospheric pressure. The higher the pressure, the more force they will put on it. This can be caused by different things, such as temperature or altitude.
So, what causes air pressure ? Air pressure is caused by the weight of the air molecules above an object. Even tiny ones have some heft, and collectively huge numbers or air molecules make up our atmosphere’s layers which press down on whatever it touches below.
How does a straw work air pressure?
As we drink through the straws, we think they work because we suck the water up.
According to science, air constantly pushes down on the liquid in the cup. When you place a straw in a cup of liquid, the air inside the straw pushes down on the liquid. Because of this, the level of liquid in the straw and in the cup are the same. By sucking on the straw, we suck out all of the air and put it into our lungs. Due to this, there is a lower pressure area inside our mouth (and on the straw as well), which means that the air pressure inside and outside the straw is no longer balanced.
Once all the air has been expelled from the straw, nothing can push down on the liquid. The liquid outside the straw is still being pressed down by air, which causes the liquid to rise up the straw to restore equilibrium. In other words, the weight of the atmosphere pushes the liquid through the straw and into your mouth, with no sucking required.
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DO STRAWS WORK IN SPACE
A straw relies on the surrounding pressure of the atmosphere to drive materials into our mouths. And because there is no atmospheric pressure in space, the straw does not work.
Imagine putting one straw in the cup, one straw out of the cup, and then trying to suck water up through the straw. Would the water come up through the straw faster, or do nothing at all?
Air moves from areas with high pressure to areas with low pressure. Taking a sip of water through a straw reduces the air pressure in your mouth and forces the water up through the straw ( from a higher to a lower pressure ).
Due to the second straw not being inside the glass, air moves up the second straw and equalizes the pressure inside your mouth with the pressure outside…and water won’t travel up the straw.
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Air pressure is an amazing thing that we use every day without realizing it. And now you know a little bit more about how it works. Whether you’re blowing up a balloon or trying to get water through a dispenser, air pressure is always at work. We hope this article has shown you some of the amazing ways air pressure can be used and given you some ideas for experiments you can do on your own. Stay tuned for more science experiments from us here at My World Their Way!
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