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Subject: Re: Class demo - whoa!
Date: Tue, 1 Feb 2005 11:05:23 -0500
Author: Don Abramowitz
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Subject: Re: Class demo - whoa!
Date: Tue, 1 Feb 2005 17:53:05 EST
Author: ACTSNYC**At_Symbol_Here**CS.COM
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Date: Tue, 1 Feb 2005 09:33:44 -0700
Reply-To: DAVID KATZ <dakatz45**At_Symbol_Here**MSN.COM>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: DAVID KATZ <dakatz45**At_Symbol_Here**MSN.COM>
Subject: Re: Class demo - whoa!
The incident with the thermite reaction occurred when a college
professor thought that it would "look cool" to replace the bucket of
sand with a large beaker of water so students could see the molten iron
under water. A number of youngsters were hurt. In his book Tested
Demonstrations in Chemistry, Hubert Alyea shows a thermit reaction using
a beaker partially filled with sand, a tin pan on top of the sand and
then the beaker is filled with water. (Demo no. 7-3) The thermite
mixture, only a few grams, is placed in a crucible. As I recall, that
professor used a 4-inch flower pot of thermite and completely
disregarded the kinetics of that quantity of material.
In defense of the thermite reaction, I do that reaction every semester
with my class when I discuss chemical reactions. We go outside, onto a
concrete patio, everyone is a minimum of 10 yards away, and a bucket of
sand is used to catch the molten iron. I explain how I grew up in
Philadelphia and how I watched repair crews fix cracks in the trolley
tracks using this reaction. It was also used to weld track together
when building the railroads. I never use the thermite reaction when
visiting classrooms or entertaining the general public.
As a chemistry teacher, I have been doing chemistry demonstrations for
over 35 years to audiences from pre-school through professional
scientists. I do at least one demonstration in every class I teach,
often more. During my career, I have done my share of fire and smoke
demonstrations, but always with a point, and always in context with a
specific topic or goal, and always with an eye on safety. Fire, smoke
and explosions are not appropriate for school visitations or public
demonstrations. I'm proud of a 100% safety record.
We became chemists because we think chemistry is a fascinating and
exciting science. Who needs magic when we can demonstrate how a glowing
splint bursts into flame in an enriched oxygen atmosphere and is then
extinguished in a beaker of carbon dioxide - that's better than magic!
I 1981 pioneered my Chemistry in the Toy Store demos and brought some
safe and fun science using toys and common materials into many
classrooms around the world.
Right now, I'm preaching to the choir, but I preach to the masses
whenever I get a chance. Unfortunately, when I approach the purveyors
of fire, smoke and explosions and point out that their presentations are
inappropriate and offer safe alternatives, my message falls on deaf
ears.
Be vigilant in your community and discourage the fire, smoke, and
explosions in your schools.
David Katz
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DAVID A. KATZ
Chemist, Educator, Expert Demonstrator, Science Communicator, and
Consultant
133 N. Desert Stream Dr., Tucson, AZ 85745, U.S.A.
Voice/Fax/Message: 520-624-2207 Email:
dakatz45**At_Symbol_Here**msn.com
Programs and workshops for teachers, schools, museums, and the public
Visit my web site: http://www.chymist.com
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----- Original Message -----
From: List Moderator
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Sent: Tuesday, February 01, 2005 6:18 AM
Subject: Re: [DCHAS-L] Class demo - whoa!
Date: Tue, 01 Feb 2005 07:45:34 -0500
From: Joe Crockett
>
Subject: Re: Class demo - whoa!
Anyone notice that none of the children have eye protection! This
story is
scary. Wasn't it about 10-15 years ago that a college prof did a
thermite
reaction for some children and let the molten iron drip into water?
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"If we knew what it was we were doing, it would not be called
research, would it?" - Albert Einstein
Joseph M Crockett
Professor of Chemistry
Bridgewater College of Virginia
Bridgewater, VA 22812
McKinney Center for Science and Mathematics - Office 307
(540)-828-5431
email: >
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