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A recent tweet from @PatriotCoburn says:

Holy Shit the protesters in Hong Kong are grabbing the canisters of tear gas dropping it into liquid nitrogen and turning it into its harmless solid form.

It shows a video of a person in a gas mask and gloves putting a smoking tear gas cannister in a small bottle, shaking it, and emptying the resultant slush on the ground.

The tweet has been retweeted around 20 thousand times, and liked over 55 thousand times and widely shared on blogs and similar.

Does this video show someone disabling a tear gas cannister with liquid nitrogen?

Oddthinking
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    Holy F*** you're frequenting some really creepy corners of the 'net... and have you read the comments? I don't think "liquid nitrogen" is really noteable, there's not many (other than the OP) who believe it. [Water works](https://www.youtube.com/watch?v=sofyWoE3YqI) [well enough](https://www.youtube.com/watch?v=VAbrQZOcGDo) (what with the agent being water-soluble). – DevSolar Sep 03 '19 at 11:30
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    If that were liquid nitrogen in there, putting a high temperature object in a closed can with it is essentially building a bomb as the heat will turn the liquid nitrogen into a gas. And to store liquid nitrogen you'd use a dewar with a glass inside layer, dropping a heavy object into that would usually shatter it. This seems very implausible to me – Mad Scientist Sep 03 '19 at 11:47
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    @DevSolar: One of the 20 thousand retweeters was one of my (normally skeptical) acquaintances, so it came to me. No shortage of notability: [here](https://www.kraftfuttermischwerk.de/blogg/wie-demonstranten-in-hong-kong-traenengas-mit-stickstoff-neutralisieren/), [here](https://www.citizenfreepress.com/column-2/hk-protester-outsmarts-the-riot-police-genius-move/), [here](https://www.snafu-solomon.com/2019/09/protesters-in-hong-kong-are-grabbing.html), etc. – Oddthinking Sep 03 '19 at 11:56
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    Well, I don't actually have something on this, other than some limited personal experience (*cough*...) and Occam's Razor: If water does the trick (as it clearly does), why would anyone go to the length of actually bringing and using liquid nitrogen (which in itself is not without its dangers)? – DevSolar Sep 03 '19 at 12:02
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    Anecdotal: I was an active participant in Istanbul Gezi protests and I did neutralize a canister or two myself. It just looks like plain water (which does the trick). – cyco130 Sep 03 '19 at 16:15
  • I've seen this reported much more frequently as water. It only seems like this one tweet nonsensically saying it is liquid nitrogen. – Bryan Krause Sep 03 '19 at 16:17
  • ["_Watch This Hong Kong Protester Instantly Neutralize Tear Gas_"](https://www.popularmechanics.com/science/health/a28904691/how-tear-gas-works/) shows the video and discusses it. – Nat Sep 05 '19 at 00:37
  • @Nat: Do you want to use that link as an answer, so I can accept it? – Oddthinking Sep 05 '19 at 02:15
  • Another factor: If they were using LN2 to freeze it, after dumping it out it would warm up and release the tear gas again. – Loren Pechtel Sep 07 '19 at 04:20

1 Answers1

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The claim is most likely false.

It's common for Hong Kong protesters to use water to neutralize tear gas. [video] [source]

While liquid nitrogen is priced similar to your average bottled water, liquid nitrogen would be impractical because is not readily available at the sites of the protests, dangerous (pressure explosion, cold burn*), and the public endangerment would be bad PR for the protesters, as well as an unnecessary legal liability.

*The cold burn video is about LPT instead of nitrogen because I wanted a source that uses innocent cartoons instead of gruesome pictures. It's safe to watch, no nasty surprises.

Peter
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    additional sources: https://twitter.com/zeynep/status/1168730000540848128 https://twitter.com/zeynep/status/1169065320113479680 https://twitter.com/zeynep/status/1169046987477413888 https://twitter.com/zeynep/status/1168731678392504320 https://twitter.com/Pinboard/status/1168741085385936896 – Federico Sep 05 '19 at 09:35