Don’t try this at home.
A video on the YouTube channel The Backyard Scientist shows what happens when a molten ball of salt is lowered into a vat of water: it explodes with tremendous power, sprouting a mushroom shape not unlike an atomic bomb, destroying the glass container.
Oddly enough, this was a counter-intuitive outcome. Usually, when molten substances are dropped in water, the Leidenfrost effect prevents any explosion from taking place. Because the molten substance is so hot, it would instantly create a wall of vapor between it and the liquid water.
The Backyard Scientist took this mystery to Reddit, which had a handy explanation.
“The steam layer rapidly becomes superheated, causing a large and almost instant increase in pressure. At the surface of the water, this high pressure steam can easily escape,” wrote one Reddit user on the Chemistry discussion area. “But as the blob of molten salt sinks deeper, the pressurised steam is confined by the water around it. This causes the pressure to rise even further, even quicker, until it overcomes the water pressure holding it back and you get an explosion.”
The Backyard Scientist has also performed this experiment with a number of metals, none of which has triggered a comparable explosion.
