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Author Topic: Could someone explain the can crushing experiment?  (Read 17381 times)

Offline ATremor

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It is an experiment I remember seeing in school. You add a couple of tablespoons of water to an aluminum can. You heat the can on the stove until the water is boiling. While the can is simmering you get another sauce pan full of cool water and keep it near by. When the water is boiling in the can, you then use a tongs and quickly turn it the can upside down into the cool sauce pan. The can is immediately crushed! What is happening exactly?
AT


 

Offline BenV

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Could someone explain the can crushing experiment?
« Reply #1 on: 09/01/2010 09:15:28 »
http://www.thenakedscientists.com/HTML/content/kitchenscience/exp/steam-powered-can-crusher/

"As you heat the can to 100C the water inside starts to boil, turning into steam and increasing in volume by a factor of about 600 times.  This steam pushes out, or displaces, most of the air in the can.

When you put the can into the cold water the sides of the can cool down rapidly, which  allows the steam to condense on the sides of the can.  This happens much too rapidly for the water to rush in through the mouth of the can and fill the space, so the pressure decreases inside the can and the external air pressure crushes the can."

Does that help?



 

Offline ATremor

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Could someone explain the can crushing experiment?
« Reply #2 on: 09/01/2010 15:21:34 »
Yup sure does! Thanks!
 

Offline blenhart

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Re: Could someone explain the can crushing experiment?
« Reply #3 on: 03/04/2012 14:06:14 »
what is the law that explains this phenomenon? the ideal gas law? the combined gas law? or is there some other force acting upon this can? plase helpppp
 

Offline daveshorts

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Re: Could someone explain the can crushing experiment?
« Reply #4 on: 21/08/2012 14:35:11 »
The reduction in pressure, so volume is to do with a phase change - going from gas to liquid. Ideal gasses don't liquify so their laws won't help you.  There are lots of equations to do with phase changes, but they are more complex, and involve more experimentally determined constants than I think you are looking for.
 

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Re: Could someone explain the can crushing experiment?
« Reply #4 on: 21/08/2012 14:35:11 »

 

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