Polarizers and Image Noise

[Mike Buckley]

resident geek here

It's always helpful to have a geek in residence. I had no idea that pure water does not conduct electricity. Is pure water defined as any material that contains two parts of hydrogen for every part of oxygen and nothing else?

[davidedric]

Is pure water defined as any material that contains two parts of hydrogen for every part of oxygen and nothing else?

Yes (leaving aside any physical aspects such as isotopes), provided that they are combined into H2O molecules. So a simple mixture of the gases in that ratio wouldn't be, but add a spark and you'd get a big bang - and water.

Though it could of course be water, ice or steam

[GiacomoD]

It's always helpful to have a geek in residence. I had no idea that pure water does not conduct electricity. Is pure water defined as any material that contains two parts of hydrogen for every part of oxygen and nothing else?

Yes Mike,
no salts, no particles, no micro-organisms, only H2O molecules. No ions, no electricity But, in practice, it exists only in chemical laboratories.

[Manfred M]

Distilled water or de-ionized water are for all intents "pure water", but you won't find that in nature. The closest you'll come to that is rain water. Water is the "universal solvent", so all kinds of dissolved minerals and suspended organic matter are found in most surface water that we see in our photography.