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Topic: Yama tabletop on the way!, (4 msgs / 295 lines)
1) From: David Adler
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Hi ,
as others have pointed out, John got the pressures on the vacuum pot  
explanation backwards.
BUT - more importantly - just in case for safety's sake:
DO NOT do the other experiment the way John describes - it's also  
backwards - it possibly will explode the container!
the actual demonstration is: put a small amount of water in the  
container, get it boiling - WITHOUT the cap.
then *take it off the heat*, screw the cap on and wait. As the steam  
turns back into water, with much less volume, the vapor pressure  
inside the can decreases below atmospheric pressure.
Then the atmospheric pressure on the outside will squeeze the can and  
it will start to collapse.
Very fun if done the right way, potentially very not fun done the  
wrong way..
.and try to pay closer attention to dad's demonstrations,
:)
David
--> wishing everyone a happy, safe, and some good coffee, New Year!
On Jan 5, 2008, at 8:01 PM, homeroast-request  
wrote:
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Hi ,as others have pointed out, John got the pressures on the =
vacuum pot explanation backwards.
BUT - more importantly - = just in case for safety's sake:
DO NOT do the other = experiment the way John describes - it's also backwards - it possibly = will explode the container!
the actual demonstration = is: put a small amount of water in the container, get it boiling - = WITHOUT the cap.then *take it off the heat*, screw the cap on = and wait. As the steam turns back into water, with much less volume, the = vapor pressure inside the can decreases below atmospheric = pressure.Then the atmospheric pressure on the outside will = squeeze the can and it will start to collapse.
Very fun if done the right = way, potentially very not fun done the wrong way...and try to = pay closer attention to dad's = demonstrations,:)David--> wishing = everyone a happy, safe, and some good coffee, New Year!
On Jan 5, 2008, at 8:01 = PM, homeroast-request@= lists.sweetmarias.com wrote:

Message: 6

Date: Sat, 05 Jan 2008 = 18:24:49 -0500

From: John Despres <john= com>

To: homeroast= s.com

Subject: = Re: +Yama tabletop on the way!

Reply-To: homeroast= s.com

It's all about atmospheric pressure and = vacuums.

...

For a fun experiment, take a metal can (my dad used to = do this for us as 

kids with a gallon maple = syrup can) with a screw top lid, add a bit of 

water and close the lid tightly. Put it = on the stove and slowly heat it. 

As the water warms, the exterior = pressure will "increase" and the can 

will begin to collapse...

Very fun, this science!

= --Apple-Mail-1-109622125--

2) From: Dave Ehrenkranz
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BTW - This also works very well with a metal pop or beer can. In fact  
all one has to do is put a little bit of water in the can and get the  
water boiling. Let it boil for a little while (this is to remove the  
air from the can as the steam displaces the air). Then remove the can  
from the source of heat, turn the can over and immediately put  into  
a pot with a few inches of cold water. The can will immediately  
collapse.
The can collapses because the steam that was in the can turns to  
liquid when put into the cold pot of water. This causes the pressure  
in the can to rapidly decrease and the atmospheric pressure outside  
the can causes the can to collapse.
dave "retired chem teacher"
On Jan 6, 2008, at 12:20 AM, David Adler wrote:
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BTW - This also works very well =
with a metal pop or beer can. In fact all one has to do is put a little =
bit of water in the can and get the water boiling. Let it boil for a =
little while (this is to remove the air from the can as the steam =
displaces the air). Then remove the can from the source of heat, turn =
the can over and immediately put  into a pot with a few inches of cold =
water. The can will immediately collapse.
The can collapses because = the steam that was in the can turns to liquid when put into the cold pot = of water. This causes the pressure in the can to rapidly decrease and = the atmospheric pressure outside the can causes the can to = collapse.
dave = "retired chem teacher" On Jan 6, 2008, at 12:20 = AM, David Adler wrote:
Hi = ,as others have pointed out, John got the pressures on the vacuum = pot explanation backwards.
BUT - more importantly - = just in case for safety's sake:
DO NOT do the other = experiment the way John describes - it's also backwards - it possibly = will explode the container!
the actual demonstration = is: put a small amount of water in the container, get it boiling - = WITHOUT the cap.then *take it off the heat*, screw the cap on = and wait. As the steam turns back into water, with much less volume, the = vapor pressure inside the can decreases below atmospheric = pressure.Then the atmospheric pressure on the outside will = squeeze the can and it will start to collapse.
Very fun if done the right = way, potentially very not fun done the wrong way...and try to = pay closer attention to dad's = demonstrations,:)David--> wishing = everyone a happy, safe, and some good coffee, New Year!
On Jan 5, 2008, at 8:01 = PM, homeroast-request@= lists.sweetmarias.com wrote:
Message: 6Date: = Sat, 05 Jan 2008 18:24:49 -0500From: = John Despres <john= com>To: homeroast= s.comSubject: Re: +Yama tabletop = on the way!Reply-To: homeroast= s.com It's all about atmospheric pressure and = vacuums....For a fun experiment, take a metal can (my dad used to = do this for us as kids with a gallon maple syrup can) with a screw top = lid, add a bit of water and close the lid tightly. Put it on the stove = and slowly heat it. As the water warms, the exterior pressure will = "increase" and the can will begin to collapse... Very fun, = this science!

3) From: John Despres
I think I was six when my dad showed us that experiment. A long time 
ago. Memory, huh...
I must have been in a backwards mode yesterday. Thanks for the 
correction, Dave
John
David Adler wrote:
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-- 
John A C Despres
Hug your kids
616.437.9182http://www.sceneitallproductions.com

4) From: Rich
I have seen this happen to 250,00 gallon storage tanks.  You can get 
your fingers caught in collapsing cans, be careful.
Dave Ehrenkranz wrote:
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