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Nails color

  1. Dec 15, 2015 #1
    Hello everyone. The title of my question may look a bit silly, but I think it is quite interesting.

    Before a couple of days, my aunt told me that she found a paint? for her nails, which had the following feature:
    her nails would have a specific color when she was in her house and a different one when she went out of it.

    That was a bit surprising and at first I could not figure out why would this even be possible. I assumed that, since the wavelength spectra of the photons that exist out of our houses is the same with the one, in them.

    Then I "stepped" on WIEN'S law and wondered if it has to do with the different temperature between inside and outside the house.
  2. jcsd
  3. Dec 15, 2015 #2
    http://www.gemstone.org/index.php?option=com_content&view=article&id=127:sapphire&catid=1:gem-by-gem&Itemid=14 [Broken]

    <<The most sensational feature about this stone, however, is its surprising ability to change its colour. Green or bluish-green in daylight, alexandrite turns a soft shade of red, purplish-red or raspberry red in incandescent light.>>

    The explanation of the phenomenon concerning Alexandrite seems this:


    Probably that nail's paint has a similar property.

    Last edited by a moderator: May 7, 2017
  4. Dec 15, 2015 #3
    Interesting, I have to admit. But it refers to incandescent light, which if I am not wrong originates for example from a lamp, in our house. Incandescent light means that is does not originate from the sun.

    On the contrary, those paints are supposed to change color under sunlight, without the use of any incandescent light.
  5. Dec 15, 2015 #4
    Another possibility would be thermochromic dyes, as in these jeans. Wien's law would not explain the colour change, as a body needs to be much hotter than room temperature for there to be a significant amount of visible light emitted.
    Last edited by a moderator: May 7, 2017
  6. Dec 15, 2015 #5
    It is more logical to have something in common with these jeans.

    Your note about Wien's law is essentially true.
  7. Dec 15, 2015 #6


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    my wife uses nail polish that changes with temperature
    pretty cool
  8. Dec 16, 2015 #7
    You wrote:
    "her nails would have a specific color when she was in her house and a different one when she went out of it.".
    I replied that Alexandrite has a specific colour as seen under an incandescent light [that is, inside home] and another under sunlight [that is, out of home]. So, what you intended exactly? That when at home she looks at her nails during the day, near an open window?

  9. Dec 16, 2015 #8
    You mean that you can understand if she is getting angry from the fact her nails' colour changes from light blue to dark red? :smile:

  10. Dec 16, 2015 #9


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    naaa, much more interesting than that :wink:

    it is quite temperature sensitive

    At the moment she has a problem with the ring finger on her left hand ( hasn't been able to wear her wedding ring for 12 months because of the swelling etc
    ( she goes in for surgery in Jan 2016 to hopefully fix the problem) ... there's tendon problem further down in the palm of the hand causing the problems

    The swelling comes and goes and when her finger is swollen it's temperature is a little higher than the other fingers on that hand and as a result the temp sensitive
    nail polish changes colour where it doesn't on the other fingernails. Just an interesting observation

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