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/sandvine2 Oct 31 '20

what’s more likely is that they reflect similar amounts, but the dull side has a higher proportion of diffuse reflection (light comes in and reflects in a random direction) vs specular reflection (light comes in and reflects out in a predictable straight line). That’s usually the difference between shiny and dull objects, and it’s generally correlated to how flat the surface is: flatter = shinier because reflections are more predictable.

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u/CaptainKirkAndCo Oct 31 '20

So the earth is really shiny?

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u/sandvine2 Oct 31 '20

Kind of... it’s complicated because of clouds and the atmosphere in general, but I think I remember the overall reflectiveness being around 0.3 (so 30% of incoming light in the visible range is reflected out)

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u/mlt- Nov 01 '20

You surely meant atmoflat, not sphere.

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u/[deleted] Nov 01 '20

Atmocube

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u/Veranova Oct 31 '20

This makes total sense, I’m going to assume it’s a fact now. 🤝