Does water conduct electricity?

05 September 2017

Question

Does water conduct electricity?

Answer

Chris Smith put this question to Jess Wade ...

Jess - This is a great question. A great nice chemistry question that you can do some experiments with at home. Basically, tap or well H2O as Thomas puts it doesn’t have any kind of ions in that could move the electricity around. So to move electricity, you need something that’s going to transport it. And you need something like the nice salt that’s in most tap water or the chlorine that’s in pool water, and these things, salt contains sodium and chlorine, and these things can catch the electricity and move it through the liquid, and take it to the other side. So, if you’ve got a battery, you could check that it’s working. You can also do another really neat experiment at home where you got those sports drinks. So, sports drinks make kind of big claims about the electrolytes that they have inside them and you can actually test that by setting up a kind of little circuit and seeing whether you could conduct through a sports drink because those things should also be able to conduct electricity. So, if you have a swimming pool, you can do it because you can use the chlorine ions. If you’ve got normal water, you can do it because it’s probably got salt in. And you can get rid of most of the minerals I think within water can't conduct. So, that’s your limiting factor there. You have lots of stuff inside normal water that you get out, but they're not conductive so you need something it can conduct.

Chris - So, would pure water, pure, clean, distilled water still conduct electricity or not?

Jess - No.

Chris - Not at all.

Jess - If it didn’t have any salt in it, it shouldn’t conduct electricity at all.

Chris - It’s a little bit ionised, so isn’t it you get a tiny bit of breaking of the – the H2O goes into a bit of H plus and a bit of OH minus so you can get a tiny, tiny…

Jess - Okay. Probably a teeny, teeny, tiny bit. But probably, nothing that we could detect.

Chris - Nothing that would be meaningful.

Jess - Nothing that would be meaningful for Thomas.

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