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FireteamAccount t1_j1np6dx wrote

Reply to comment by ShxxH4ppens in How is density measured in porous materials? by That_Lego_Guy_Jack

Archimedes is also iffy above a certain porosity where the fluid will start to penetrate the sample. You will get the wrong measurement. You can smear some grease or coating on the outside to reduce interaction with the liquid.

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Level9TraumaCenter t1_j1p72x7 wrote

I've used nitrogen for pycnometry instead of helium; some really porous samples I've tested would cause the instrument to drift and never really settle down, but nitrogen (being heavier AND diatomic) gave "better" (faster) numbers.

Very different, but also interesting- BET surface area analysis.

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ShxxH4ppens t1_j1nps6j wrote

Yeah, depends what kind of resolution is required for analysis

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ACuteMonkeysUncle t1_j1r56x1 wrote

Is this like what happens when you add 50 cL of alcohol to 50 cL of water and get less than 100 cL overall?

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