this post was submitted on 23 Oct 2025
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xkcd #3158: Shielding Chart

Title text:

Sharks can occasionally travel short distances through air when pursuing prey, but their attenuation coefficient is pretty high.

Transcript:

Transcript will show once it’s been added to explainxkcd.com

Source: https://xkcd.com/3158/

explainxkcd for #3158

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[–] ludrol@bookwyr.me 19 points 1 month ago

the demon core for neutron source is funny

[–] jawa22@lemmy.blahaj.zone 13 points 1 month ago

This is the best one in quite a while imo.

[–] LawfulPirate@sh.itjust.works 10 points 1 month ago* (last edited 1 month ago)

Lead/Water type has pretty good defensive coverage but sound and heat might be dominant

[–] Landless2029@lemmy.world 3 points 1 month ago (1 children)

Am I wierd for wanting a poster of this?

[–] RebekahWSD@lemmy.world 1 points 1 month ago

Not weird at all! It would be a good poster!

[–] muzzle@lemmy.zip 2 points 1 month ago

Neutrinos are sorely missing

[–] Zoomboingding@lemmy.world 2 points 1 month ago (1 children)

Armor would block radio waves?

[–] Linen04@lemmy.world 2 points 1 month ago

Yes, a complete set of metal armor would work as Faraday cage

[–] mEEGal@lemmy.world 1 points 1 month ago

Heat ç sound are the hardest to block

[–] Devjavu@lemmy.dbzer0.com 1 points 1 month ago (1 children)

Why does the faraday cage not have a gray, but a purple? I thought it completely blocks radio.

[–] Scirocco@lemmy.world 2 points 1 month ago* (last edited 1 month ago) (1 children)

It depends on the wavelength of the radio waves.

This is visible in microwaves, where the wavelength is about 12cm, but the tiny holes of 1mm are small enough that zero (or super tiny?) radiation/radio/EM in that wavelength can pass through, but light (visible light that you can see) has a much, much smaller wavelength and passes just fine.

So, you could say that a larger mesh (chain link fence?) of conductive material is also a faraday cage, but only affects things with a really large wavelength.

thus, faraday cages have a variable effect, depending on their configuration.

[–] Devjavu@lemmy.dbzer0.com 1 points 1 month ago

Yeah, I did read some time ago that the max hole size was like half the wavelength and there existed also a penetration depth. I guess this makes sense with light making it through fences.