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Does cacao powder form another "state of matter"?

  1. Oct 24, 2015 #1
    In another forum someone states that "cacao powder" cannot be considered as a "solid state" since "it cannot sustain shear stresses".
    Has this statement any basis?

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  2. jcsd
  3. Oct 24, 2015 #2

    mfb

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    It can, in a very limited amount. That's not the point, however. It is made out of solid pieces.
     
  4. Oct 24, 2015 #3

    sophiecentaur

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    Is there a reference to specific experiments?
    It seems to me that it's probably just the consequence of insisting on classifying things where it's not appropriate. There are so many examples of substances that don't fall into the standard three or four groups. We've all played with Cornflour (I don't mean Maize Flour but I don't know the US term for it) suspensions and seen Non Newtonian behaviour. Then there are the thixotropic paints. Life's too short, imo.
     
  5. Oct 24, 2015 #4

    Dale

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    I would go with sophiecentaur's signature on this one.
     
  6. Oct 24, 2015 #5

    Vanadium 50

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    I think it's a bad idea to argue with people across forums.

    You can make the same argument, to a lesser degree, about a pile of fine sand. Or coarse sand. Or gravel. These are all solids.
     
  7. Oct 24, 2015 #6
    No, for the moment.
    Sure, I'm asking if there is or not a definition like that (or others) about a "solid substance". If there aren't, the problem is closed, for what concerns me.

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    BlueRay
     
  8. Oct 24, 2015 #7
    Thank to all for the answers.

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  9. Oct 24, 2015 #8
    I think you mean cornstarch. :)
    Is Cornflour a brand name?
     
  10. Oct 24, 2015 #9

    sophiecentaur

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    Cornflour is what we have (always) called the white stuff that is the main consituent of Birds Custard and other sauces. It's a generic term in the UK (what it says on the labels). There was not much Maize grown or sold in the UK and 'corn' was only in Cornflakes or Cornflour; mostly wheat flour has been used. I recently made some corn tortillas and had to search hard for cornmeal - even in health food shops. The lack of gluten made them devils to stay together on the pan until cooked. Cracked it though.
     
  11. Oct 24, 2015 #10

    Andy Resnick

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    Powders, emulsions, foams, colloidal dispersions, etc. are sometimes classified as 'soft matter' systems: nonlinear, nonergodic, non-newtonian, etc. etc.
     
  12. Oct 24, 2015 #11

    Vanadium 50

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    The idea that solids, liquids and gasses form three distinct phases with huge gaps with no gray areas or fine lines is very middle school. You can buy one micron latex spheres. They come in a bottle, and look like a milky liquid. But each sphere is solid.
     
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