Recent comments in /f/askscience

Navvana t1_j1pa6pc wrote

Reply to How is density measured in porous materials? by That_Lego_Guy_Jack

Look into void fractions or porosity. There are a number of methods depending on the material and what you’re goal is.

They revolve around different techniques to measure the volume of the pores/void spaces. Which then allows you to subtract it from the overall volume of the material when calculating density.

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Beaulderdash2000 t1_j1p9h2q wrote

Reply to comment by [deleted] in I recently learned that humans can smell rain / petrichor (ozone and geosmin) better than sharks smell blood, now considering we don't have any extra hyper specific olfactory organs like some other animals do, how do we achieve this level of detection? by Corvuscoraxaphro

Its the smell of fresh rain specially that this study refers to. Not just water. But, the evolutionary advantage of being able.to smell rain on the wind, could have been very successful.

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SockPoop t1_j1p8f20 wrote

Reply to comment by SalomeFern in I recently learned that humans can smell rain / petrichor (ozone and geosmin) better than sharks smell blood, now considering we don't have any extra hyper specific olfactory organs like some other animals do, how do we achieve this level of detection? by Corvuscoraxaphro

OP is not talking about photocopiers. Ink and UV light to cure wett ink is a different printing tech than what you'd typically see in an office photocopier.

That being said xerographic printers (laser printer), typically found in office settings, generate ozone as part of the process. Ozone has always been that "copy machine" smell to me.

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SalomeFern t1_j1p6rqj wrote

Reply to comment by [deleted] in I recently learned that humans can smell rain / petrichor (ozone and geosmin) better than sharks smell blood, now considering we don't have any extra hyper specific olfactory organs like some other animals do, how do we achieve this level of detection? by Corvuscoraxaphro

Are photocopiers not meant to smell like that? I kind of like the funky smell, I just thought it was normal for those machines.

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superbob201 t1_j1p44qw wrote

Reply to What is the currently-accepted theory for how the moon was formed? by CopperGenie

Still the generally accepted answer. One fairly recent modification is that it looks like Theia hit Earth twice. Still not a perfect theory: some isotope ratio studies don't quite match the model, and our computer models of the collision suggest Theia was going slower than we would reasonably expect (Which itself could mean that Theia started life as an Earth-Trojan

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