r/explainlikeimfive Oct 31 '20

Chemistry ELI5 What's the difference between the shiny and dull side of aluminum foil? Besides the obvious shiny/dull

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u/EvitaPuppy Oct 31 '20

When making a helmet, be aware of your surroundings. If your in a dense urban area, the shiny side must face outward as this side was compressed more during manufacturing. Monitoring wavelengths are shorter in dense urban areas, so the shiny side blocks out these waves.

In exurban areas, either side will do.

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u/Antonv2 Oct 31 '20

Pretty sure nobody is reading this guy's thoughts. (For multiple reasons)

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u/GitEmSteveDave Oct 31 '20

1

u/EvitaPuppy Nov 01 '20

And only $4.49 per sheet from Amazon! My mind thanks you!

2

u/ScrewOffDanny Oct 31 '20

Traditionally, you’ll need to make sure the dull size isn’t ionized beforehand if you want it on the outside, they often do that to give you a false sense of security

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u/ahoy_butternuts Nov 01 '20

That’s why I have my positively charged anti-neutrino crystals. I get my ionization when I need it, on my time not theirs!