I'm not gonna ask my science teacher as that YouTuber suggested because when I showed my science teacher a disk magnet that only attracted metal on one side, she said this happens when you split disk magnet exactly in half.
I believe if he used sand instead of salt result would be exactly the same. Nothing special about the salt. Just surface tension of mercury not letting it pass through.
From the clips at the end of the video where he cuts open a balloon full of mercury and it goes splashing everywhere, right out of the bucket all over his driveway - he doesn't seem very qualified to be handling an extremely toxic heavy metal, and I don't want to think about what the next property owner is going to face, especially if the house uses well water, or worse, is near a public well's aquifer.
Did I mention that mercury evaporates in air? So if he's been doing anything in enclosed spaces, his house is contaminated?
Anyone want to place bets on whether all the things he gets mercury on are properly handled like the hazardous waste they are, or he just collects what he can, shrugs, and throws the rest in the trash?
It's a little more complicated than that. A pile of salt doesn't have nearly the cohesion that the ground does, and mercury only resembles a ball when you take surface tension into account. Both very scale-sensitive questions. But mostly yes, it looks like surface tension is the answer.
The mercury is denser than his hand but strangely, it doesn't go through? Similarly, it also doesn't go through salt grains until you stir them due to surface tension.
