2 HN users recommended this explainer2 months2015–2024score 2
Years with an HN recommendation, 2007–2026
HN links it as the accessible video explanation of the sodium-in-water research, and when Coulomb explosions or sodium batteries come up.
Thunderf00t presents high-speed camera footage of alkali metals such as sodium and NaK reacting with water. The footage shows that the explosion is not caused by hydrogen ignition, as the usual explanation says. It is a Coulomb explosion driven by electrons leaving the metal.
“the video has a nice balance, it's technical but not too technical” (HN, 2023)
That's the video from before they published (which is still interesting). There is also a more recent video[1] (post-publication[2]) that covers how they got the data (which supports the coulombic explosion hypothesis). While it is mentioned at the end of the newer video, I highly recommend watching the 500fps footage[3] of a drop of NaK burning (just before it explodes) on the top of water. There is a striking color change as it starts to interact with the water, and right the NaK explodes... the metal turns completely transparent . [1] [this video] [2] [link] [3] [link]
The article in Nature is about a paper by Thunderf00t (Phil Mason). He published the result in Nature Chemistry and also made a video [this video] (the video has a nice balance, it's technical but not too technical).
Technical but accessible video on the Nature Chemistry paper
Yep, all batteries and capacitors amount to is electron storage devices. Capacitors are much more prone to becoming coulomb bombs than batteries mostly because they are designed to discharge quickly, which is what makes them implicitly good bombs. It doesn't take much electron movement to make an explosion. In fact, this is how alkali metals react with water. We learnt that only in the past few years. [link] [this video]
> Really makes you wonder at what other interesting phenomenon are happening in plain sight we've yet to notice. It happens all the time, and is both exciting and a little worrying (because it implies that basic effects that we should already understand, we actually seem to misunderstand quite often). As an example of this, we didn't have a full explanation for why alkali metals seem to explode when you put them on water until YouTube when Phil Mason (thunderf00t) started working on it[1] -- the classic explanation was that it was because of the hydrogen gas released, but this didn't make sense because they would also explode under water. There was a Nature article about it[2], but the gist of it is that once the alkali metal melts and sheds its oxide surface due to the high heat of the reaction there are solviated electrons in the water that attract the metal surface and causes spikes to shoot out from the metal which then cause more spikes and then it all goes bang (because reactions can only happen on the interface -- having more surface area causes more of a reaction) once the surface tension breaks. This also explains why thermite explodes when you put it on ice and similar effects. And the solution to stop these sorts of explosions (which are obviously a hazard for people who work with alkali metals) is to add a weak surfactant (like soap). [1]: [this video] [2]: [link]
Thunderf00t's work on why alkali metals explode in water
The author of the research paper is Phil Mason (Thunderf00t on YouTube). He has another paper[1] and video[2] about making sodium+potasium explode in water. [1] [link] [2] [this video]
Explain the wrong reasoning and flaws in these videos: [link] [this video] [link] [link] [link] I will take your words by face value and assume that none of these videos used or needed any amount of intellectual rigor and that he is not very smart. Okay, but if the bar is that high, then it appears that whatever scam kickstarter he debunks wasn't even on the scale of intellectual rigor or smartness.
That makes a lot of sense... thanks! As for molten salts and water... oh yeah. That gets into very dangerous territory.[1] A very similar reaction seems to happen even with just molten table salt, where it "shouldn't". 1 - [this video]
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