Absolutley pure–no inclusions.
I thought it would, being polar and all, but my instructor said it won’t.
Really?
My chem teacher in high school did this experiment once. No pure H2O doesn’t conduct electricity. As i remember it has something to do with the partiles dissolved in water ionizing? Hmmmmm let me think, yep thats the extent of my chemistry knowledge.
IANAP but I can tell you that anthing will conduct electricity eventually. The old statement used to by there is no such thing as an insulator, only conductors with varying degrees of resistance. Pure latex rubber will conduct electricity if you pour a large enough current into it. Of course it then apparently bursts into flame, but hey.
Water of course will conduct electricity relatively easily because pure water isn’t. Assuming we’re talking water exposed to normal atmosphere it’s actually a weak carbonic acid solution, and any dilute acid will conduct a charge relatively eaily since by definition it consists of dissociated ions in an aqueous solution.
Water in noble gas atmosphere would I assume conduct current less well since it should contain no appreciable concentrations of ions, but even here there would be some voltage at which the resistance of the water would break down.
Very pure water has a resistance of about 18.3X10[sup]6[/sup] Ohms/cm.
Here’s a company that sells lab grade water purifiers.
Yes, pure water will conduct electricity, but poorly. It’s only when impurities are added that it becomes a better conductor. The more electrolytes, the better. The goal is to get the electrolytes to dissolve into ions. Sodium and potassium work well. Ammonia, however, would not.
Since H[sub]2[/sub]O is polar, the molecules will tend to align with an electric field pushed through them, but remember that current is the flow of charges and since water molecules are neutral, they CAN’T carry current. You have to either have ions present (like in tap water, water exposed to the atmosphere, etc) or else a strong enough current to force the electrons through the water despite the tendency the water molecules will have to try to grab them.
Very pure water does have ions in it, OH[sup]-[/sup] and H[sub]3[/sub]O[sup]+[/sup] (the products of self-ionization). It can use these to conduct electricity, but they are in such low concentrations in pure water that it will have very high resistance.
Oddly enough my roommate and I were just talking about this today because his physics lecturer demonstrated that in fact pure (or close to it anyway) does conduct a very small amount of electricity… contrary to what I was told in every chem class I’ve ever taken.
I have seen electric eels in the Cleveland Aquarium zap their prey, using the conductivity of water (i.e. the conductivity of water plus whatever is dissolved in it). So how come the eels themselves don’t get zapped by their own charge?
For some reason I thought there was a Cecil column on this, but I couldn’t find it.
http://www.sciencenet.org.uk/database/Biology/0104/b00906d.html says it might have something to do with their skins, but they’re not really sure.
Throw the switch, Igor!
Now live, my creation! Live! Live! LIIIIIVVVVVEEEEE!!!
Demonstration I saw done in chem class:
Wire up a pair of electrodes and light bulb (regular 60W incandescent) such that if you short together the two electrodes, the bulb will light up.
Dip two electrodes into flask of distilled water. No light. Or at least, not enough light to be noticeable to a lecture hall of 200 students.
Dip the same two electrodes into flask of tap water. Bulb lights up brightly.
Of course, that video doesn’t actually demonstrate that pure water will not conduct electricity, like it says it does – it just demonstrates that it doesn’t conduct it very well, or enough to be dangerous when flushing it through a running hair dryer and on your hands and whatnot. Though I guess it could be argued that this is what “does not conduct electricity” means to most people.
I like what Gaspode said in post 3, nearly 13 years ago – there’s no such thing as a real insulator, just conductors of varying degrees of resistance. Heh…
I used to work in quartz crystal manufacturing*, and we measured the cleanliness of the crystals during cleaning by the resistance of the water. We used a ton of de-ionized water that flowed over the crystals removing any contaminants. When everything was removed, the resistance of the water was very high and we regarded them as clean. I don’t remember how high the resistance got, but I think it was in the mega-ohm range.
*The crystals eventually went into two way radios, pagers, and cell phones.
The water in homes is not pure, so it conducts well.
My science teacher ran a current through distilled water, connected to a light bulb. The bulb remained dark until he added a little salt. Since no one’s house uses distilled water, the water will conduct, and usually quite well.
Actually 22 MOhms is pure water.
And after a mere 13 years I’m sure Squink is glad of the correction. 
zombie or no
something missing there.
This sitehas five references, four of which agree with 18.2 M Ohm-cm at 25 C. The last reference there is for 25 M Ohms-cm, but at 20 C.
The fourth reference gives a range of 18.2 to 40 Ohm-cm, varying with temperature, with 18.2 at for 25 C, and rising to 40 as the temperature drops to 10 C. Unfortunately, this reference is a stale link.