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Drop your most "wtf that's not how the world works" from movies/tv shows. (lemmy.world)

submitted 3 weeks ago by ericbomb@lemmy.world to c/memes@lemmy.world

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I'm aware of the NCIS scenes, what else you guys got?

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[-] ContrarianTrail@lemm.ee 52 points 3 weeks ago

Sprinklers react to heat, not smoke and they don't all go off at once. Also the water that comes out is brown from rust, not clear.

War bows are so heavy that you can barely hold it for the moment it takes to aim. There's no way you're holding it for minutes before told to release.

[-] AVincentInSpace@pawb.social 15 points 3 weeks ago* (last edited 3 weeks ago)

Fire sprinklers have two requirements: to be able to turn on immediately if they're ever needed, and to dispense something capable of extinguishing a fire. In order to accomplish this, the pipes that feed them are constantly, 24/7, full of water, providing constant pressure on the sprinkler head to be ready to feed it with water in case it ever needs to go off. These water pipes are generally not used for anything else, so the water does not tend to circulate. In fact, there's usually a sensor in them that detects if the water is flowing (and thus if any sprinklers have been triggered, providing somewhere for it to go) and activates the building's fire alarm. When a fire sprinkler goes off, the water that comes out has been sitting in that pipe (an iron pipe if you're lucky, a lead pipe if you're not) basically since the building was built.

That stuff is NAS-T.

[-] ContrarianTrail@lemm.ee 11 points 3 weeks ago

When replacing thermostat valves or radiators in buildings with steel-pipe radiator lines, the water that comes out is often as black as ink. It’s surprising how dark it can get.

And for anyone wondering why steel is used, yes, it does rust, but only while there’s air in the water. As the pipes start rusting, that air gets used up, and the rusting stops. Same applies to sprinkler lines. Steel pipes in radiator lines can easily last the building’s lifetime, whereas copper pipes for drinking water usually need replacement every 30 years or so.

[-] Agrivar@lemmy.world 5 points 2 weeks ago

Copper pipes only need replacing that often if a) you cheaped out on construction and used the thinnest kind (M-type, which isn't even legal in some states), and b) you had some pressure issue along the way that left the pipes only partially full of water for a time.

[-] AVincentInSpace@pawb.social 5 points 2 weeks ago* (last edited 2 weeks ago)

I'm reminded of a Linus Tech Tips video in which they built a gaming PC with the express purpose of heating a room/house. To do this more effectively, they connected a bog-standard water cooling loop to an actual radiator like you would find plumbed into an old building, instead of using a purpose built PC water cooling radiator like every other water cooled PC ever built (I guess because they either thought it wouldn't dissipate enough heat (in which case why not just use more of them?) or because they forgot those existed). They flushed the radiator with water and vinegar before putting it to work and what came out of it was... colorful. Even after flushing it much more thoroughly, after putting it into the final setup, the system did not perform anywhere near as well as expected due to the copper water blocks inside the PC getting covered in rust and stopping conducting heat. Those systems are no joke.

[-] HawlSera@lemm.ee 3 points 2 weeks ago

So Postal 2 (Where you throw a lit match directly at one) is accurate?

[-] ContrarianTrail@lemm.ee 5 points 2 weeks ago* (last edited 2 weeks ago)

I haven’t seen that movie, but you’d need to hold the match there for a while. Inside the sprinkler head, there’s a small glass vial with liquid. When it heats up enough it expands, the glass breaks, releasing the water behind it.