scilearner Posted April 20, 2010 Share Posted April 20, 2010 Hello guys, This is simple question but I have gone completely blank. Ok let's say there was a balloon outside that was inflated. This means that it has expandes so it's pressure is equivalent to atmpospheric pressure right? So when I pinch it why does air escape, how does balloon suddenly have higher pressure to make air move out? Is pinching the balloon equivalent to making the volume of the ballon smaller. Thanks Link to comment Share on other sites More sharing options...
Moontanman Posted April 20, 2010 Share Posted April 20, 2010 No, the pressure inside an inflated balloon is greater than the surrounding atmospheric pressure, when you make a hole all the air rushes to go out to the lower pressure outside through hole. Link to comment Share on other sites More sharing options...
scilearner Posted April 20, 2010 Author Share Posted April 20, 2010 No, the pressure inside an inflated balloon is greater than the surrounding atmospheric pressure, when you make a hole all the air rushes to go out to the lower pressure outside through hole. Thanks for the response If the balloon is in equilibrium how come its internal pressure is not equivalent to atmospheric pressure? Do you mean that the ballon does expand because it has higher pressure but it can only do that for a certain limit. Link to comment Share on other sites More sharing options...
Sisyphus Posted April 20, 2010 Share Posted April 20, 2010 Remember that you are stretching out the elastic balloon. The inside pressure has to fight both the outside pressure and the elasticity of the balloon. Think of stretching out or compressing a spring - to maintain a shape other than its nautral shape requires a constant force. Link to comment Share on other sites More sharing options...
scilearner Posted April 20, 2010 Author Share Posted April 20, 2010 Remember that you are stretching out the elastic balloon. The inside pressure has to fight both the outside pressure and the elasticity of the balloon. Think of stretching out or compressing a spring - to maintain a shape other than its nautral shape requires a constant force. I see thanks for the help However the balloon might expand atleast a little bit if I suddenly decrease the atmospheric pressure right? It might not equalize it. Link to comment Share on other sites More sharing options...
Sisyphus Posted April 20, 2010 Share Posted April 20, 2010 Sure, if you decrease outside pressure, it should have the same effect as increasing inside pressure. Link to comment Share on other sites More sharing options...
Moontanman Posted April 20, 2010 Share Posted April 20, 2010 I see thanks for the help However the balloon might expand atleast a little bit if I suddenly decrease the atmospheric pressure right? It might not equalize it. Yes, increase or decrease the ambient pressure the balloon will respond by getting larger or smaller, decrease the ambient pressure enough and the balloon will explode. Link to comment Share on other sites More sharing options...
Mr Skeptic Posted April 20, 2010 Share Posted April 20, 2010 Yes, increase or decrease the ambient pressure the balloon will respond by getting larger or smaller, decrease the ambient pressure enough and the balloon will explode. Which helium-filled balloons will do when you release them and they float upwards to where the air is less dense. Link to comment Share on other sites More sharing options...
rooshidavid Posted April 22, 2010 Share Posted April 22, 2010 I state that any balloon filled with helium gas in good amount will go so denser but i thinks the perfect answer for this question is Promotional Balloons. Link to comment Share on other sites More sharing options...
insane_alien Posted April 22, 2010 Share Posted April 22, 2010 roosh, ummm what? can you rephrase that so it makes sense? Link to comment Share on other sites More sharing options...
khaled Posted April 22, 2010 Share Posted April 22, 2010 Heat [math]\propto[/math] Pressure also, Speed [math]\propto[/math] Pressure gas inside the balloon escapes High-Pressure, but if the balloon is kept under the water, it won't lose gas from its pressure, but because the high pressure of the water causes it to press on the balloon and enforce its gas to escape, but gas won't escape it if the container is solid ... Link to comment Share on other sites More sharing options...
insane_alien Posted April 22, 2010 Share Posted April 22, 2010 Heat [math]\propto[/math] Pressure also, Speed [math]\propto[/math] Pressure only in an isolated system, a balloon is not an isolated system. but if the balloon is kept under the water, it won't lose gas from its pressure, but because the high pressure of the water causes it to press on the balloon and enforce its gas to escape, but gas won't escape it if the container is solid ... this is muddled. gas can and will still escape underwater. also, many gasses can diffuse through apparently solid materials. such as helium through steel. Link to comment Share on other sites More sharing options...
Moontanman Posted April 23, 2010 Share Posted April 23, 2010 Not to mention how fast helium difuses through a rubber balloon. Ever put propane in a balloon? Link to comment Share on other sites More sharing options...
khaled Posted April 23, 2010 Share Posted April 23, 2010 Ever put propane in a balloon? it will be like "flying mines to heat", lol Link to comment Share on other sites More sharing options...
Moontanman Posted April 23, 2010 Share Posted April 23, 2010 it will be like "flying mines to heat", lol Actually a balloon full of propane drops like a rock, propane is so heavy the behavior of a balloon full of it acts really weird after you have been used to balloons full of hydrogen or even air. Link to comment Share on other sites More sharing options...
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