Another possibility is that the demo involved molten potassium chlorate – also known as the gummy bear immolation demonstration. A small piece of candy, such as a gummy bear is dropped into molten potassium chlorate - a dramatic red flame (that can sho ot out several inches from the reaction) immediately is produced via the sugar in the candy reacting with the oxygen in the molten KClO4 and the flame heatin g the K+ ions. Afterwards, everything in the immediate area is covered with K Cl. I’ve done this one several times in the past, but always in evaporati ng dishes, never out of a test tube. Nowadays, I would never do this in a classroom.
From:
Sent: Monday, January 25, 20
10
8:32 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Possible
cause
for this HS chem accident
I think I have a possible cause for this HS chemistry class acciden t. I asked one of our researchers here who was a former food science chemist. Sh e said that it if the teacher used the SOUR flavor, they set up an incompatib le reaction.
Ta rtaric acid is used in the food industry to make the "sour" taste for gu ms and candy. The JT Baker MSDS for potassium chlorate (http://www.jtbaker.co m/msds/englishhtml/P5620.htm) specifical ly lists tartaric acid as an incompatible material:
Incompa
tibilities:
Iodides, tartaric acid, aluminum, sulfuric acid, hypophosphite, powdered
metals, organic matter and many other oxidizable substances.
It is also possible that all of the candy/gum wrapper was not removed and the caused a more vigorous reaction than anticipated.
Th is experiment, which appears to be common in HS chemistry classes, should have the following safety instructions included for all who demonstrate this reactio n:
1.
Read the
MSDS for all chemicals before you use them. Make sure to read more than 1
manufacturer's MSDS - not all listed the specific chemical incompatabilitie
s.
2.
Do not
use the SOUR flavor for the candy.
3.
Check all
glassware for any nicks, scratches, etc. Do not use if present.
4.
Use a
plexiglass or lexan shield between the students and the demonstration.
Th
ese
shields can be purchased from Fisher (cat.# 1429340), VWR, Flin
n (cat. #SE225) or other companies. They are expensive, but ca
n be
made relatively cheaply - buy a large sheet of lexan or plexiglass 5 to 20
mm
thick and ask the Tech Teacher to cut it and mount it on a metal base.
Re member that the OSHA Lab Standard requires that there are written protocols for al l experiments. These protocols must include the safety requirements! font>
Kim
Auletta
Teacher r
By JAY BRAMAN JR.
BOICEVILLE — The explosion on Tuesday
that
injured an
Donald Bucher was demonstrating an experimen
t 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 condu
cted
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 Wedn
esday,
r
“We still don’t know what
happened,” the superintendent said. “But we will debrief Mr. Bu
cher
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 h
ome
were not answered on Wednesday.
The seven students who were injured, all
11th-graders, were treated at
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.<
br>
“The goal of the experiment was to det
ermine
the amount of oxygen in the potassium chlorate,” Ford said.
The superintendent said possible causes of t
he
accident were a faulty test tube or the chemical itself being compromised.<
/font>
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 Uls
ter
BOCES, Ford said.
O’Rourke said on Wednesday that the ch
emical
will be disposed of properly and other chemicals in the school will be chec
ked
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 firewor
ks;
as a disinfectant; and as an oxidizing agent. It forms a flammable mixture
with
combustible materials, and the mixture can be explosive if combustible mate
rial
is finely divided.
Potassium chlorate can be ignited by frictio
n, and
contact with strong sulfuric acid may cause fires or explosions, according
to
the Web site. Also, it may spontaneously d
Ulster County Emergency Management Director
Art
Snyder appeared before the Onterora Board of Education during the body̵
7;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.
Lab Safety Specialist
EH&S
Stony Brook University
kauletta**At_Symbol_Here**notes.cc.sunysb.edu
631-632-3032
EH&S Web site: http://www.stonybrook.edu/ehs/lab/
__
___________________________________________________________________<
/font>
Published: Thursday, January 21, 2010
Correspondent
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 prop
erly
on Wednesday.
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