Dumping Molten Salt Into A Tank Of Water

[Cascabel]

http://www.sciencealert.com/watch-something-crazy-happens-when-this-scientist-adds-molten-salt-to-water

 

Does anyone understand what is happening here?

[CraigD]

What caught my attention in the TheBackyardScientist “molten salt into water” videos is that the salt sinks and cools with little effect when it is heated to just over it melting point. When the experiment is repeated with the salt much hotter, the bit steam explosion happens. So this is some sort of critical temperature “tipping point” effect.

 

What I think is happening agrees, I think, with what the narrator/experimenter guesses, though he doesn’t discuss it in much detail – when the salt is below a critical temperature, it’s contained and kept out of contact with the water by a layer of steam – a variation of the Leidenfrost effect – so cools gradually and unspectacularly. When it’s over a critical temperature, it’s not contained, but shoots droplets into the water, and has water shot into its main body, cooling suddently in a runaway, expanding ball of steam – the glass tank-breaking explosion seen in the video.

 

It’s a complicated dynamic, surprising dynamic, that I wouldn’t have imagined in my wildest guesses. That’s what’s so cool about actually doing experiments, even informal ones like TheBackyardScientist’s.