A video shows liquid mercury sitting on top of table salt. Even though the mercury is much denser, it does not sink to the bottom.

Why does this happen? Is the mercury just so thick that it is like pouring honey on flour?

  • 2
    $\begingroup$ Did you click on the link at the end of the video that links to the explanation... $\endgroup$ – hft May 1 '15 at 5:35

In a subsequent video the same person attributes the phenomenon to mercury's high surface tension and non-wetting, non-wicking chemistry. Mercury makes a convex meniscus at the interface between the mercury and a dry surface. The gaps between the salt grains are smaller than the radius of this meniscus, so the mercury can't flow between them to lift them up.


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