Date: Mon, 2 May 2011 14:52:14 -

Author: --- "Zani, Gerald"

Subject: Re: Liquid Nitrogen and Ice cream

Post:

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One year a biology professor complained when she saw the grad students make
LN ice cream with their research dewars and their LN and give the ice cream
to children.

I thought hell would reign.
But nothing came of it.
Maybe not a good practice?

Better to buy an ice cream machine and use either dry ice or H2O ice that is
super-hardened with LN? - Jerry

On Mon, May 2, 2011 at 2:39 PM, David Sturm wrote:

> Another thing to consider: not much is dissolvable in LN2.
> "Safety" people think every liquid is like water, the universal solvent.
>
> I usually use clear or white balloons to demonstrate LO2 forming
> inside an air-filled balloon immersed in LN2. When I use the party
> store Helium tanks (the disposable pink steel tanks), I also see LO2
> forming in side a supposedly He-filled balloon. I suspect this is because
> they back fill the He with air? Never have that issue with real He
> tanks.
>
> The worst thing I get accumulating in the bottom of dewars is iceballs,
> from humidity condensing anytime the caps are off.
>
> Nitrogen will pour through cheesecloth, if you want to "filter" it?
>
> An intriguing question though, Stephen.
>
> David
>
> **Physics Days at Funtown/Splashtown USA May 19-20, 2011
> ====================================================
> David E G Sturm - sturmde@maine.edu - 1.207.581.1241
> --Physics & Astronomy Instructional Laboratories
> --Bennett Hall Lecture Demonstration Facilities
> --Mainely Physics Road Show --PIRA Past President '09-'10
> Dept of Physics & Astronomy -- University of Maine
> 5709 Bennett Hall -- Orono ME 04469-5709
> http://www.physics.umaine.edu/
> =============================================
>
>


--
Gerald Zani
Demonstration Manager
Physics
Brown University
(401) 863-3964

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One year a biology professor complained when she saw the grad students make=
LN ice cream with their research dewars and their LN and give the ice crea=
m to children.I thought hell would reign.=A0 But nothing came o=
f it.

Maybe not a good practice?Better to buy an ice cream machine and us=
e either dry ice or H2O ice that is super-hardened with LN? - Jerry=
On Mon, May 2, 2011 at 2:39 PM, David Sturm @umit.maine.edu> wrote:

Another thing to =
consider: not much is dissolvable in LN2.
"Safety" people think every liquid is like water, the universal s=
olvent.

I usually use clear or white balloons to demonstrate LO2 forming
inside an air-filled balloon immersed in LN2. =A0When I use the party
store Helium tanks (the disposable pink steel tanks), I also see LO2
forming in side a supposedly He-filled balloon. =A0I suspect this is becaus=
e
they back fill the He with air? =A0Never have that issue with real He
tanks.

The worst thing I get accumulating in the bottom of dewars is iceballs,
from humidity condensing anytime the caps are off.

Nitrogen will pour through cheesecloth, if you want to "filter" i=
t?

An intriguing question though, Stephen.

David

**Physics Days at Funtown/Splashtown USA May 19-20, 2011
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D
David E G Sturm - sturmde@maine.edu - 1.207.581.1241
--Physics & Astronomy Instructional Laboratories
--Bennett Hall Lecture Demonstration Facilities
--Mainely Physics Road Show --PIRA Past President '09-'10
Dept of Physics & Astronomy -- University of Maine
5709 Bennett Hall -- Orono ME 04469-5709
http://www.phy=
sics.umaine.edu/
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

-- Gerald ZaniDemonstr=
ation ManagerPhysicsBrown University(401) 863-3964

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