[neact] Re: More on HS chlorate explosion-tsw reply
- From: Jerusha Vogel <jj@xxxxxxxx>
- To: neact@xxxxxxxxxxxxx
- Date: Fri, 22 Jan 2010 19:10:49 -0500
Oops, I knew that - thanks for the correction. It was KClO3 that I used.
That's what comes from typing when the kids are clamoring for food. So you
think this demo could be used successfully and more safely with the
potassium perchlorate?
JV
From: neact-bounce@xxxxxxxxxxxxx [mailto:neact-bounce@xxxxxxxxxxxxx] On
Behalf Of Ted Wysocki
Sent: Friday, January 22, 2010 6:40 PM
To: neact@xxxxxxxxxxxxx
Cc: ted w
Subject: [neact] Re: More on HS chlorate explosion-tsw reply
As I read throught the e-mails I find that KClO4, which is actually
Potassium Perchlorate, is being referered to as Potassium Chlorate.
Potassium Chlorate is KClO3.
I have worked with both in an explosives/ pyrotechnics company, and found
formulations using as the oxidizer KClO4 being less sensitive than those
made with Potassium Chlorate.
We also found slight traces of copper or copper compound increased the
sensitivty.
Could someone tell me which of these two compounds was used, ...that
resulted in the explosion?
Ted.
_____
Date: Fri, 22 Jan 2010 17:37:00 -0500
From: jj@xxxxxxxx
Subject: [neact] Re: More on HS chlorate explosion
To: neact@xxxxxxxxxxxxx
This is a very popular demo with the kids and I have done this many times
with the gummy bear with no problems. You heat a pyrex test tube with a
small amount of KClO4 over a Bunsen burner. It liquefies and decomposes.
You can see a white cloud of gas moving up the test tube. At this point I
do the oxygen test to show the kids the identity of the gas and then to
finish it off, I throw a gummy bear in. A light purple flame that looks
like a blow torch comes shooting out as the sugar reacts - it's a great demo
that can demonstrate flame tests, types of reactions, and even review the
electron movement in the potassium atom causing the violet color! My
colleague was doing this same demo in the hood in front of her class when
the oxygen produced got trapped under some liquefied KClO4 and cause it to
splatter outward violently. The teacher was burned on her hand and wrist by
the molten KCl. Since it was in a hood no kids were hurt, but we started
using heavy gloves when doing the demo. My school had the hood in the
middle of the room so the kids could be on one side looking through the
glass, while I was on the other with the glass partly up to reach in. That
made it even safer for the kids - but few rooms are set up that way.
Jerusha Vogel
From: neact-bounce@xxxxxxxxxxxxx [mailto:neact-bounce@xxxxxxxxxxxxx] On
Behalf Of Lois Ongley
Sent: Friday, January 22, 2010 5:00 PM
To: neact@xxxxxxxxxxxxx
Subject: [neact] Re: More on HS chlorate explosion
Speculation would indicate that it was just potassium chlorate heated with
stick of gum dropped in. A common enough HS experiment on You tube as gummi
bear sacrifice.
Lois Ongley
From: neact-bounce@xxxxxxxxxxxxx [mailto:neact-bounce@xxxxxxxxxxxxx] On
Behalf Of Kenneth Bowers
Sent: Friday, January 22, 2010 4:49 PM
To: neact@xxxxxxxxxxxxx
Subject: [neact] Re: More on HS chlorate explosion
I have conducted what I believe is the same experiment many times.
I always have done the experiment outside.
Can you provide more information on the catalyst used ?
Was concentrated sulfuric acid part of the experiment ?
Retired now from full time teaching. I still work on a regulart basis as a
substitute.
Kenneth Bowers
On Jan 22, 2010, at 12:22 PM, Stephen Stepenuck wrote:
Some follow-up info on the high school potassium chlorate explosion. This
too is from the ACS Division of Chemical Health and Safety's email list.
This account seems to me to be a strong argument for purchase and use of
portable safety shields, and long heavy gloves for the teacher.
[Apologies for accidental post earlier. Maybe when I'm 137 I'll learn to
triple-check the address line...]
Steve
* * * * * * *
New York
http://www.dailyfreeman.com/articles/2010/01/21/news/doc4b57e5a7a57482739218
60.txt
Teacher recovering; cause of blast uncertain
Published: Thursday, January 21, 2010
By JAY BRAMAN JR.
Correspondent
BOICEVILLE - The explosion on Tuesday that injured an Onteora High School
chemistry teacher and seven of his students came as a surprise to everyone,
but probably no one more than the longtime teacher himself.
Donald Bucher was demonstrating an experiment with the chemical potassium
chlorate when the explosion - which was strong enough to damage a window in
the classroom - occurred. Onteora school district Superintendent Leslie Ford
said on Wednesday that Bucher had conducted the same experiment dozens of
times before, without incident, and that the cause of the explosion remained
a mystery.
Ford said Bucher was resting at home on Wednesday, recovering from his
injury, and that an investigation of the incident will begin shortly.
"We still don't know what happened," the superintendent said. "But we will
debrief Mr. Bucher when he is well enough to return."
Ford said a small piece of glass punctured Bucher's arm and cut an artery.
"He was bleeding quite a lot," she said.
A reporter's calls to Bucher's home were not answered on Wednesday.
The seven students who were injured, all 11th-graders, were treated at
Kingston and Benedictine hospitals, primarily for minor cuts, and released.
Ford said the explosion occurred when Bucher dropped a stick of gum into a
test tube containing potassium chlorate, a chemical used in matches,
explosives, gunpowder and fireworks.
Ford said school district officials reviewed the chemistry class' lesson
plan and concluded the experiment had been performed safely by Bucher in the
past. She also said it is a standard high school chemistry experiment and
that Bucher executed each of its steps properly on Wednesday.
"The goal of the experiment was to determine the amount of oxygen in the
potassium chlorate," Ford said.
The superintendent said possible causes of the accident were a faulty test
tube or the chemical itself being compromised.
All the remaining potassium chlorate in the classroom was removed, bagged
locked in a secure location elsewhere in the building by Michael O'Rourke of
the Risk Management Department at Ulster BOCES, Ford said.
O'Rourke said on Wednesday that the chemical will be disposed of properly
and other chemicals in the school will be checked for problems.
According to a Web site co-maintained by the National Oceanic and
Atmospheric Administration, potassium chlorate is a white crystalline solid.
It is used in matches, explosives, gunpowder and fireworks; as a
disinfectant; and as an oxidizing agent. It forms a flammable mixture with
combustible materials, and the mixture can be explosive if combustible
material is finely divided.
Potassium chlorate can be ignited by friction, and contact with strong
sulfuric acid may cause fires or explosions, according to the Web site.
Also, it may spontaneously decompose and ignite when mixed with ammonium
salts and may explode under prolonged exposure to heat or fire.
Ulster County Emergency Management Director Art Snyder appeared before the
Onterora Board of Education during the body's regularly scheduled meeting
Tuesday evening. He outlined the procedures for hazardous materials
disposal, though Ford noted the procedures were not required in Tuesday's
incident.
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