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Whistling iron and sulfur

  1. Nov 5, 2009 #1
    I quote from a fellow chemistry teachers' letter (Mike Thompson):
    "Many colleagues will know that when solid sulphur is heated below some lightly packed iron wool in a test tube or boiling tube a standing wave is sometimes set up and a whistling noise is heard (around middle C with a boiling tube). The noise may be heard whether the reaction is incandescent or not. There is no obvious visible vibration of the iron wool or of the sulfur vapour. The noise can sometimes last for 60 seconds or more. I have tried to get the same noise using phosphorous and iodine with iron wool but without success. I have posted a clip on YouTube. "

    To which I replied:
    I tried two more experiments:
    1. Using copper wool instead of iron wool, one gets this effect, though not as impressively. It seems to me that it only starts, in this case, when the reaction is taking place (while with iron wool I think it it can start before). Maybe it is temperature dependent.
    2. Using pyrex wool, which obviously does not react with the sulphur, one can also get this effect. I think it has to be loosely packed, as it didn't work every time I tried.

    Since then I came across a reference dating back over 70 years: http://www.iop.org/EJ/abstract/0959-5309/46/1/311
    which may be relevant.

    I don'y have solid CO2 available, but it would be interesting to try putting it in a test tube with iron wool, and seeing (!) if one gets the same effect.

    I am posting this in the hope that someone can give us an explanation as to how the phenomenon is caused.

    Thanks, Yehoshua
    Last edited by a moderator: Sep 25, 2014
  2. jcsd
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