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Subject: Re: [DCHAS-L] Chemical Shelving Heights
Date: Thursday, June 27, 2019 at 6:56:16 AM
Author: Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU> 		Next by Date:
Subject: Re: [DCHAS-L] Chemical Shelving Heights
Date: Thu, 27 Jun 2019 11:56:55 +0000
Author: Stanley C. Howell

From: Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
Subject: Re: [DCHAS-L] [EXT] Rainbow Flame Demo Alternatives
Date: Thu, 27 Jun 2019 11:56:07 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 1000811206.724143.1561636567236**At_Symbol_Here**mail.yahoo.com
In-Reply-To <5d1457f2.1c69fb81.2929a.40f5**At_Symbol_Here**mx.google.com>


Meg, Isn't it interesting how you have to defeat the proclivities of students to develop a lack of respect for the properties of their materials such as acids by keeping them from exposure to them. It seems explaining the hazards to them doesn't work.  

It's the difference between the child who can understand the verbal warning about your tongue sticking to a metal flag pole in winter, and one who just seems to have to find out for themselves.   But today, we reorganize the whole lesson to protect the kid who will put his tongue on the pole.  And perhaps that's the reason we see so many bad decisions by adults who have never experienced the consequences of not listening to their teachers.

And yes, the wire loop took some doing.  For example, It didn't work for me the first time.  Instead, I learned that a wire that LOOKS clean may still not BE clean.  And you had to be rather dexterous and patient to get the bead to form on the wire -- a skill under-developed in the generation that thinks with their thumbs.

But from what you describe, the stupidity of the student and the teacher's liability for that stupidest student is the driving factor in your design of lessons.  

In other words,

1.  All of your reasoning for the choice of materials, why they work better, and why provide more lessons is absolutely brilliant.  

2.  The reason you have to think and plan this way is what is disturbing.

Monona




-----Original Message-----
From: Meg Osterby <megosterby**At_Symbol_Here**GMAIL.COM>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Thu, Jun 27, 2019 5:39 am
Subject: Re: [DCHAS-L] [EXT] Rainbow Flame Demo Alternatives

Monona,
 
While teaching at Western, I moved away from the solutions with Pt wire loop, because the loop needs to be cleaned between solutions in order to avoid cross contamination and un-interpretable results.  The wires are generally cleaned by swishing several times in an acid solution, typically 1M or 3M HCl.  However, this use seemed to make my students become cavalier using acids and even splash it and not do anything to clean it up.  Also, the acid solution becomes progressively more contaminated, and therefore cross contaminates the solutions with each other, giving meaningless results.  I didn't like making the students lose respect for acids, and I didn't like that the results were hard to see and interpret.  My students did 6 known solutions and then 3 unknown ones (three of the same salts) and they had a lot of trouble with the identifications with the wire loop in solutions method..
 
I saw the wood-stick cotton swab method in the Flinn Catalog (although more recently they espouse soaking wood splints in aqueous solutions of the salts.  The cotton swabs are wet with distilled water (they keep a beaker on the bench with tap water half filling it) by holding the tip over the beaker and using their distilled water wash bottle to wet it and the beaker to catch the excess water.  Then, they placed a microspoon of the solid for that test into one of the shallow wells of a spot plate, roll the wet swab tip in the solid, then put that tip in the hottest part of the flame.  The colors were bright and unequivocal, and the students never failed to identify their three unknowns.  When the stick catches on fire, they place the flaming swab into the beaker of water.
 
I liked this method better than the wood splint method, because the salt stays on the swab, and since the salts don't burn, having it just as visible on the swab provided an easy way to demonstrate that.  (The metals in the salt get excited, moving an electron to a higher level, from which it falls emitting light.)  Since the salt doesn't burn or disappear, the students can SEE that burning it isn't what causes the color.  The salts don=E2=80™t change on the swab, and the students can see they don't.
 
So even if the wire loop method with solutions of the salts is easy, the dampened cotton swab rolled in the salts gives better results.  And it doesn't require students using acid, in a way that familiarity leads to disrespect or contempt.  And that leads to the potential of future accidents.
 
Meg
 
Meg Osterby
megosterby**At_Symbol_Here**gmail.com
"It's better to be careful 100 times than to be killed once." Mark Twain
From: Janice Umbaugh
Sent: Wednesday, June 26, 2019 6:00 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] [EXT] Rainbow Flame Demo Alternatives
 
Just thinking outside the box here: it might be possible to not use flames at all and instead direct a light source through a synthetic gemstone or a piece of stained glass and make the same observations with a spectroscope. Both stained glass and synthetic gems are doped with certain elements like chromium and strontium to produce colors. The down side is that you may not be able to get all the elements that are usually flame tested. The up side is that your synthetic ruby is probably not going to set anyone on fire.
While the starting cost might be an issue for some teachers, you can get a synthetic ruby (doped with chromium) for less than the list price of a bottle of chromium trioxide, and it has an interesting spectrum. You could probably just glue the pieces on a light table with black paint or paper to block out the light so that it only shines through the crystal.
I haven't actually tried the stained glass, so I don=E2=80™t know how that would work. I'd be glad to know if anyone else thinks this might be feasible.
Janice Umbaugh
 
 
From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Samuella Beth Sigmann
Sent: Tuesday, June 25, 2019 11:50 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] [EXT] Re: [DCHAS-L] Letter to the National PTAregarding the rainbow flame demo
 
Yes.  We currently do this as an experiment with aqueous solutions and get very nice colors with the chloride salts of K, Ba, Sr, Na, Li, Cu, Ca.  They can even observe and measure the spectral lines with spectroscopes.
Sammye
On 6/25/2019 11:09 AM, Monona Rossol wrote:
100 years ago when I was in qualitative analysis, we did it our damn selves in the lab.  We made saturated solutions and used a platinum wire loop to get enough liquid in the loop to see an nice clear colored flame.  Do they still do that?
 
Monona
-----Original Message-----
From: Meg Osterby <megosterby**At_Symbol_Here**GMAIL.COM>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Tue, Jun 25, 2019 5:18 am
Subject: Re: [DCHAS-L] [EXT] Re: [DCHAS-L] Letter to the National PTAregarding the rainbow flame demo
The KCl flame was very hard to see.  I have done this demo with (wood stick) cotton swabs, wet with distilled water and the tip rolled in the solid.  The color is bright and long lasting and the purple/pink in the flame is easy to see.  It=E2=80™s the only way I know of to do KCl and get such a good color.
 
Meg Osterby
W831 County Road K
Stoddard, WI 54658
414-539-1543 (cell)
608-788-7951 (home)
megosterby**At_Symbol_Here**gmail.com
"It's better to be careful 100 times than to be killed once." Mark Twain
 
From: Patricia Redden
Sent: Monday, June 24, 2019 10:39 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] [EXT] Re: [DCHAS-L] Letter to the National PTAregarding the rainbow flame demo
 
Looks great, Marta.
 
On Mon, Jun 24, 2019 at 9:25 AM Gmurczyk, Marta <M_Gmurczyk**At_Symbol_Here**acs.org> wrote:
Dear All:
I have been following the discussion regarding the rainbow flame demo. My colleague Kim Duncan and I have collaborate to put together the following site related to the safer flame tests.
 
If you have any suggestions how to improve this page, please let me know. Please feel free to use this page in your communications with teachers.
Sincerely,
Marta Gmurczyk
 
 
Marta U. Gmurczyk, Ph.D.
Safety Programs Manager| Scientific Advancement Division
1155 16th St., NW | Washington | DC 20036
T 202-452-2105 | F 202-872-8068
www.acs.org
---=E2=80"-------=E2=80"--------
ACS Chemistry for Life
American Chemical Society
 
 
 
 
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> On Behalf Of Mary Shane
Sent: Sunday, June 23, 2019 11:14 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [EXT] Re: [DCHAS-L] Letter to the National PTA regarding the rainbow flame demo
 
I have done this as a microscale lab.  I make the solutions before hand and never have the alcohol still in the lab.  I use small candles  and cotton swabs.  It has worked safely but I can see where it can go wrong.  I am going to try the method mentioned using long cotton swabs soaked in distilled water and dipped in the salts.  If it gives the same results, I will switch to the new method and share with my colleagues.  We have been told not to use methanol and I have only used it for this lab.  I think the AP Chemistry teacher used it last year.  I will be that teacher this next year and will look to see if methanol can be completely removed.  
 
On Sat, Jun 22, 2019 at 12:43 PM Eric Goff <ericwgoff**At_Symbol_Here**gmail..com> wrote:
I agree with Peter.

What we do is soak cotton swabs (The long Q-tip type ones) in
distilled water for about an hour. Dip the end in the various salts
and get the same result when burning. Others use wooden stirrers /
popsicle type sticks and do the same and get the same result.

Perhaps we should be assisting those in the classroom with viable
alternatives for this and other activities.

Best Regards,

-Eric

On 6/22/19, pzavon**At_Symbol_Here**rochester.rr.com <pzavon**At_Symbol_Here**rochester.rr.com> wrote:
> One thing I notice about this letter and many other comments about
> this demonstration directed to educators is the frequent absence of
> guidance on how to perform it more safely, or on alternative, less
> hazardous, demonstrations that would illustrate the same principles.
> In my experience, it is usually more effective to provide alternatives
> than to simply say "don't do that."
> Decades ago, my then boss at Princeton University used to say to
> faculty members something along the lines of "I am not telling you
> that you can't to that; I am telling you that you can't do it in the
> way you have been accustomed to doing it."
> Peter Zavon, CIHPenfield, NY(on location in Cincinnati, OH)
>
>       -----------------------------------------From: "davivid"
> To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
> Cc:
> Sent: Friday June 21 2019 6:36:30PM
> Subject: [DCHAS-L] Letter to the National PTA regarding the rainbow
> flame demo
>
> Here is a letter I just emailed to the National PTA. Let's hope this
>  helps get some progress on the issue.
>
>  Dave Lane
>  Principal
>  Clavis Technology Development
>
>  -------- Forwarded Message --------
>  Subject: Dangerous classroom demonstration
>  Date: Fri, 21 Jun 2019 15:31:09 -0700
>  From: davivid
>  To: info**At_Symbol_Here**pta.org
>
>  Dear PTA Gatekeeper
>
>  I write to call your attention to a common classroom demonstration
> that
>  injures students in several incidents every year. I hope that the PTA
>
>  can help end this practice by informing parents and schools of the
> danger.
>
>  The demonstration is typically called the "Rainbow Flame" or similar.
> It
>  involves solutions of various metal salts dissolved in alcohol that
> are
>  set on fire. The different metal salts give various colored flames,
>  hence "rainbow flame". If alcohol is poured near flame or other
> ignition
>  source the alcohol can suddenly erupt from the bottle in a phenomenon
>
>  called "flame jetting". The jet of flaming alcohol can severely burn
>  anyone in the path of the flames even as far as ten feet away.
>
>  Here are some links describing flame jetting.
>
>   Dangerous =E2=80=98Flame Jetting' Phenomenon Kills Hundreds Every Year
>
>  Here are links to some recent instances of flame jetting that have
>  injured students
>
>
>
> Links:
> ------
> [1] https://www.youtube.com/watch?v=kkBFG1mTSBk
> https://www.youtube.com/watch?v=kkBFG1mTSBk
>  /> A Safer
>
>
> ---
> For more information about the DCHAS-L e-mail list, contact the Divisional
> membership chair at membership**At_Symbol_Here**dchas.org
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>


--
Best Regards,

-Eric

Eric W. Goff
Chemistry Educator

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--
******************************************************************************
We, the willing, led by the unknowing, are doing the impossible for the ungrateful. We have done so much, for so long, with so little, we are now qualified to do everything with nothing. Teresa Arnold paraphrased from Konstantin Josef Jire=C4=8Dek (1854 - 1918)
 
Samuella B. Sigmann, MS, NRCC-CHO
Chair, ACS Division of Chemical Health & Safety, 2019
Senior Lecturer/Safety Committee Chair/Director of Stockroom
Chemistry
Appalachian State University
525 Rivers Street
Boone, NC 28608
Phone: 828 262 2755
Fax: 828 262 6558
Email: sigmannsb**At_Symbol_Here**appstate.edu
 
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