kitchen table math, the sequel: They do what they do

Saturday, January 4, 2014

They do what they do

In the Times:

Only weeks before a chemistry experiment sent a plume of fire across a Manhattan high school science lab, engulfing two students and leaving one with life-threatening burns, a federal safety agency issued a video warning of the dangers of the very same experiment, a common one across the country.

The agency, the United States Chemical Safety Board, distributed the video warning to its 60,000 subscribers, a spokeswoman, Hillary Cohen, said Friday, but it had no sure way to reach individual teachers at schools like Beacon High School on the Upper West Side. There on Thursday, Anna Poole, a young science teacher known for safety consciousness, used methanol as an accelerant to burn dishes of different minerals in the chemistry demonstration known as the Rainbow.

With about 30 students watching from their desks, a snakelike flame tore through the air, missing the students closest to the teacher’s desk, but enveloping Alonzo Yanes, 16, searing and melting the skin on his face and body, according to witnesses. He was in critical condition on Friday in the burn unit of NewYork-Presbyterian Hospital/Weill Cornell Medical Center, Myrna Manners, a hospital spokeswoman, said.

Another student, Julia Saltonstall, 16, saw her thin T-shirt burned off her torso in an instant as some of her long dark hair went up in smoke, her father said. Though she was no farther from the demonstration than Alonzo, she escaped with only first-degree burns.


The safety board’s video, and an accompanying message, did not say the Rainbow demonstration should be banned, but warned that accidents have repeatedly occurred because of the volatile material involved.

“What we need to look at is why is this accident keeps happening across the country,” said Mary Beth Mulcahy, a former high school science teacher who is now an investigator with the safety board, which has documented at least seven similar accidents, including a 2006 case featured in the video that left a 15-year-old girl in Ohio, Calais Weber, with severe burns over more than 48 percent of her body. “What do we need to do to stop the cycle?”

As a 23-year-old teacher, Dr. Mulcahy added, she herself did the rainbow demonstration, unaware of the potential dangers. The visually exciting demonstration shows how different substances produce flames of different colors because of their varying properties. But she added, “I can’t imagine a teacher would do this demonstration if they knew the potential risk they were putting students in.”

Said Ms. Weber, now a pre-med student in Boston: “I read this article last night about the New York students and honestly, I cried. I can’t believe this keeps happening.”



ChemProf said...
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ChemProf said...

The room clearly had inadequate ventilation for a chemistry lab - our labs have the air completely refreshed six times an hour and that's without the hoods. So there's the first issue - chem classes without real lab spaces. But part of the problem is actually the safety culture.

The classic way to do this is to dissolve the salts in water and then have students put a drop on the end of a metal rod and burn it in a Bunsen burner. We do this in first year chemistry lab (as our second lab). It is pretty and you can introduce periodic trends. But it does have students close to fire and you have to talk about safety quite a bit, and the flames you make are very small so wouldn't be seen in the back of a classroom. Can't do that in high schools, so instead teachers look for flashy demonstrations. But flashy demos are more likely to go wrong and in chemistry, when things go wrong they go really wrong. Which is a major reason that discovery learning never took over in my field - no one wants to hand a first year student a bucket of nitric acid and hope for the best.

Barry Garelick said...

In high school, our chemistry teacher demonstrated the thermite reaction. He did so very carefully, and after the molten iron dripped into a basin of water below the stage of the combustion, he warned us to not touch anything, but just to look. One student ignored the warning and touched the iron in the water and burnt his finger. Not seriously, fortunately. Some high school students are quire impulsive.

lgm said...

Cost savings mean large lab sections here. Hard to demo and control class simultaneously. Classes are mixed ability.

Jen said...

Another example (like Khan Academy) where something that has been added as part of a "hands-on, group learning, fun and motivating" curriculum is actually the reverse.

That is, these are both so old-school in terms of their presentation that they somehow seem new and different.

Khan was addressing the lack of basic skills and practice thereof in his nephews (?). But, he soon learned that the big money now in education (the Gates, Broad, RttT, Walton family) needed it to be presented differently -- not the material, not his set-up, but the reasoning behind it and how it was sold. Voila, the flipped classroom.

There's really little less "conceptual" or higher-level thinking or any of those other buzzwords than Khan Academy or this sort of demo, but it's all part of the confused stew we've ended up with.

Jen said...

P.S. -- the experiment as described by ChemProf is much more "progressive" and educational. The students actually have to perform lab operations. They learn about safety. They (I'd guess) have to take observational notes and then use those observations to organize their data and create a written framework/explanation for the observations.

In short, THEY would be doing the actual work of taking the lecture and reading material and coming up with a product that shows they understood what they did and learned.

On an test, this type of learning also lends itself to assessment -- the student, using the knowledge they've gained would either predict a result (with reasoning) or explain a given result.

Anonymous said...

What I don't get is this:

If the teacher didn't know that this experiment is dangerous, how is she qualified to teach chemistry?

cranberry said...


cranberry said...

Is there a course on teaching chemistry in ed school? Such a course should logically include lab and demonstration safety.

Logically, required professional development in the field could include updates and refresher courses on, well, teaching chemistry safely.

On a different issue, posting a video on a website was evidently not sufficient to get the word out to America's chemistry teachers. Perhaps an old-fashioned letter or urgent email to high schools or state departments of education would have been a better choice.

The American Chemical Society might have been a good place to start. They do offer lesson plans and professional development for teachers. Their "rainbow experiment" does not involve methane, rather students neutralize acids and bases in paper cups. It's a much tamer experiment.

Part of the problem could be that there are two (or more) "rainbow experiments" in high school chemistry.

A larger part of the problem though is that videos are a terrible method of communication.

ChemProf said...

Chemistry teachers in high school don't need to have majored in chemistry or even have taken college level General Chemistry. To be well qualified, they just have to pass the praxis exam in Chemistry (which is roughly at a first year college level). I have a student who is entering a credential program and planning to teach high school chemistry (and fortunately is a chem major so does have good safety training) but nothing she will take next year is chemistry related or focused on lab safety. In fact, her cohort is mostly made up of future math teachers. So no, you can't assume that a chemistry teacher has any significant grounding in chemical safety or hygiene. Which is another reason they shy away from experiments that carry any risk (so that high school chem labs tend to be really dull, hence the desire for flashy demos).

I don't know that most high school teachers check out ACS materials, but it wouldn't hurt.

There is another "rainbow" experiment for indicators, but there are also safer ways to do the flame test experiment.

Anonymous said...

"Chemistry teachers in high school don't need to have majored in chemistry or even have taken college level General Chemistry."

Those who can't do, teach.


momod4 said...

When I was in college in the 60s, the wash-out rate for nursing majors was huge and the ones who survived through the sophomore year often transferred (like many other transfers) into the ed school. Having taken inorganic and organic chem, anatomy & physiology and microbiology, they already had met the science requirements for the secondary ed program.

gasstationwithoutpumps said...

On the AP Chem e-mail list, there has been a lot of discussion of this experiment, with some teachers admitting that they used to do it, but most feeling that methanol was just too volatile and dangerous for a lab that was not much more than a "look at the pretty colors" lab.

One recommendation was to dip wood splints in salt solutions and burn them (no methanol involved). The colors aren't quite as pure, because of sodium from the wood.

The recommendation from the author of the Pearson chemistry text was to dip Q-tips in salt solutions. (I suppose then sticking the Q-tip in a Bunsen burner flame.) The claim was made that the Q-tips did not ignite as long they stayed wet, so the flame color from the salt was pretty good. I'd want to use paper, not hollow-plastic swaps if I were doing this.

ChemProf said...

Q tips work pretty well, although again you can't see the color in the back rows if the teacher does it. But yeah, the plastic ones would be a bad idea.

Even if they do catch fire, it is easy enough to drop them into a beaker of water, and they won't burn fast, but again that makes teachers nervous if students are doing it.

ChemProf said...

And following up on momof4's comment -- the inorganic and organic chemistry that nursing students take is a one year survey course, not the two year sequence that a science student would take. The first semester of the nursing course isn't far at all from a basic high school chemistry course.

VickyS said...

I watched the Safety Board's video. I expected it to tell the chem teachers why this experiment was unsafe, and how to do it more safely or substitute another experiment as discussed in the comments here. Instead, it's a monolog from the girl who got injured in 2006, and *she* is the one who is advocating for more lab safety. While touching, it doesn't do anything to educate a chem teacher. A missed opportunity.

Also, why wasn't this video sent to the NSTA (National Science Teacher Association)? There were/are ways to get important safety information in front of science teachers.

gasstationwithoutpumps said...

The AP instructor recommending the Q-tip approach said that he'd been doing it for years with hollow plastic cheap cotton swabs with no problems. The cotton is put into the base of the flame. I tried it with kitchen salt (NaCl) and epsom salts (MgSO_4 on my gas stove. The sodium flame was a bright yellow, but I couldn't see any change from the magnesium. Perhaps there is good reason that the magnesium demo is usually done with metallic magnesium rather than magnesium sulfate.

ChemProf said...

Magnesium salt doesn't make a colored flame (it emits in the IR which in a flame is not interesting). The magnesium demo isn't a flame test, more about how magnesium is flammable (and produced a bright white, i.e. colorless, flame).

If you want colors, you want potassium (pink), lithium (red), calcium (red), or strontium (green).