From: DAVID KATZ <dakatz45**At_Symbol_Here**MSN.COM>
Subject: Re: [DCHAS-L] 4L filter flasks
Date: Fri, 13 Sep 2013 03:00:25 -0700
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: BLU180-DS16763FB257E25726C6BC92C53B0**At_Symbol_Here**phx.gbl
In-Reply-To


Instead of purchasing a large filter flask at a high price, just use a video camera to project the live demonstration, in  a 250-mL or 500-mL filter flask, on a large screen in the lecture hall.  Check the filter flask, before use, for scratches or chips and use proper clamping and safety shielding of the apparatus.
 
As an alternative, use a bell jar and vacuum apparatus to do this demonstration in a beaker.  Again, project the demonstration on a large screen.  Safety shields are still recommended.  Protect your vacuum pump from the water vapors with a trap.
 
You probably want to use room temperature water for the demonstration, but you can get reasonable results with warm water in the filter flask using a good water aspirator.
 
I also use large 140-mL or 100-mL plastic syringes (never glass) with end caps, containing a small amount of water, which can be passed around the room so students can repeat the demonstration at their seats.  Occasionally, a student will pull the plunger completely out of the syringe splashing the water, but you can minimize that by cautioning the students in advance.
 
David  
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  David A. Katz             
  Chemist, Educator, Expert Demonstrator, Science Communicator, and Consultant  
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----- Original Message -----
From: Samantha D
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Sent: Thursday, September 12, 2013 8:09 AM
Subject: Re: [DCHAS-L] 4L filter flasks

Hi all,

I'm looking for a 4L filter flask for a demo but they all seem to be $150-$250. We are creating a vacuum in order to boil water. It needs to be that big because of the size of the lecture hall. Does anyone have a good website to turn to for glassware like this?

Thank you,

Sam


On Thu, Sep 12, 2013 at 10:56 AM, Samantha D <samantha.dannenberg**At_Symbol_Here**gmail.com> wrote:
Hi all,

I'm looking for a 4L filter flask for a demo but they all seem to be $150-$250. We are creating a vacuum in order to boil water. It needs to be that big because of the size of the lecture hall. Does anyone have a good website to turn to for glassware like this?

Thank you,

Sam

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