From: Debbie M. Decker <dmdecker**At_Symbol_Here**UCDAVIS.EDU>
Subject: [DCHAS-L] Rainbow Demonstration - New and Improved!
Date: Fri, 20 Jun 2014 15:55:33 +0000
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: 3e8a46102a4d4fe5afbf92af53bc782c**At_Symbol_Here**

Hi and Hello:


To my distress, I discovered this demonstration is used frequently in my Department.  I asked one of my staff to determine a better, safer way to accomplish the demo.  She took on this project with gusto and wrote me a very nice report (which will be submitted to JCHAS).


But here’s the basic information:


New Instruction 4 – Wooden Applicators Soaked in Saturated Salts Solutions

Saturated salt solutions were prepared according to the table below. See Demo Prep Notebook#1 pg 5 for exact preparation. Note g were added to 250ml DI water (not brought to volume).




g in 250 mL H2O

BaCl2/BaCl2 • 2H2O




CuCl2 • H2O











Salts solutions were prepared in DI water. Five Wooden applicators were broken in half and placed in a weight boat. The saturated solutions were poured into the weigh boats to cover the applicators. Solutions were allowed to evaporate. Most salt solutions evaporated in 1 week. CaCl2 and LiCl were still damp after 4 months.


Salts Results:

Barium Chloride BaCl2*2H2O  (light green) - color flame clearly distinguishable

Calcium Chloride CaCl2 (orange red) – color flame clearly distinguishable

Copper Chloride CuCl2 (blue/green) – color flame clearly distinguishable

Lithium Chloride LiCl (fushia flame) – color flame clearly distinguishable

Potassium Chloride KCl (light lilac) – color flame distinguishable (better than any other tested)

Sodium Chloride NaCl (yellow flame) – color flame clearly distinguishable

Strontium Chloride SrCl2 (red or crimson flame) – color flame clearly distinguishable


Flame Tests were performed on damp CaCl2 and LiCl. All other salts were dry. Wooden applicators need an additional flame source to burn.  Just burning applicators alone did not produce a flame able to be seen from more than a feet away.  A Bunsen burner or handheld propane torch were used with similar results.  Results were spectacular, even potassium chloride was able to be seen.


If you have any questions, feel free to contact me.



Debbie M. Decker, CCHO

Safety Manager

Department of Chemistry

University of California, Davis

122 Chemistry

1 Shields Ave.

Davis, CA  95616





Birkett's hypothesis: "Any chemical reaction

that proceeds smoothly under normal conditions,

can proceed violently in the presence of an idiot."





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