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 

Be vigilant in your community and discourage the fire, smoke, and 
explosions in your schools.

David Katz 
Chemist, Educator, Expert Demonstrator, Science Communicator, and 
133 N. Desert Stream Dr., Tucson, AZ 85745, U.S.A.
Voice/Fax/Message: 520-624-2207     Email: 
Programs and workshops for teachers, schools, museums, and the public
Visit my web site:
  ----- 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 
  reaction for some children and let the molten iron drip into water?

  "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

  email: >

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