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Why doesn't a fluorescent lamp implode and shatter ?

  1. Feb 2, 2016 #1
    Accoring to Wikipedia, the pressure inside a fluorescent lamp is 0.3% of the atmospheric pressure, so the pressure difference between the outside and the inside of the lamp is almost equal to the atmospheric pressure which is 1 bar or 14.7 psi.

    Now according to this and this, glass shatters at an overpressure of about 1 psi, and sometimes even less than that.

    So why doesn't the difference in pressure between the outside and the inside of a fluorescent lamp cause the glass to shatter ?
  2. jcsd
  3. Feb 2, 2016 #2


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    Staff: Mentor

    The article is referring to windows, which are flat. Arches (tubes)are much stronger.
  4. Feb 2, 2016 #3
    So if the lamp shape was rectangular for example, would it shatter ?
  5. Feb 2, 2016 #4


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    Science Advisor
    Gold Member
    2017 Award

    Yes; unless the glass was very thick. The principle of using curved surfaces for vacuum vessels is pretty universal. CRTs, radio valves, dewar flasks . . . . .
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