tag:blogger.com,1999:blog-8964719845369935777.post6681587448494613271..comments2024-03-27T21:23:40.339-04:00Comments on Chemjobber: In defense of the rainbow flame demonstrationChemjobberhttp://www.blogger.com/profile/15932113680515602275noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-8964719845369935777.post-90022506438085631662014-11-04T17:51:41.290-05:002014-11-04T17:51:41.290-05:00I think part of the problem is many of these demos...I think part of the problem is many of these demos have not been updated for modem technology. We keep using the same stuff from the 50s.<br /><br />Why do so many of these demos use a burning beaker of methanol rather than a Bunsen burner (either portable off a small butane tank or hard lined)? A portable Bunsen burner is ~$50 online and a blowtorch with piezo-electric ignition is $19.99 at the hardware store. It seems as though simple updates could make a big difference.<br /><br />Also rather than methanol for the metal salts, using ethanol, isopropanol, or diluting with water would all lower the vapor pressure of the flammable gas and help mitigate the risk of some of the demos.<br /><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8964719845369935777.post-28668633908405730672014-10-31T11:31:38.415-04:002014-10-31T11:31:38.415-04:00Thanks VTJ for a well-written defense of the metha...Thanks VTJ for a well-written defense of the methanol experiment. I think your point at the end of the second paragraph about students going into the real world thinking chemistry is too dangerous is a good one. In addition to the wow factor, I think demos like this can teach that chemicals don't need to be feared but treated with respect. That seems particularly salient in an era of food babes, 'chemical-free' products, and widespread chemphobia. It definitely sends the wrong message to avoid doing experiments and demos that can be done safely with appropriate precautions.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8964719845369935777.post-59494945499993668202014-10-31T10:30:12.432-04:002014-10-31T10:30:12.432-04:00Why not burn the methanol in an alcohol lamp? We ...Why not burn the methanol in an alcohol lamp? We used to use them in middle school (admittedly, 50 years ago) to heat slides and nichrome wire loops in bacteriology experiments. I don't recall any problems with that approach. oldnukenoreply@blogger.comtag:blogger.com,1999:blog-8964719845369935777.post-33945209461531407442014-10-31T09:58:12.012-04:002014-10-31T09:58:12.012-04:00I think VTJ's idea of a blog for demonstration...I think VTJ's idea of a blog for demonstrations is excellent. It would be the best way to make information available to the greatest number of people.qvxbnoreply@blogger.com