Negative Ion Generators

[hessian]

How can one demonstrate in the home that these simple devices are generating negative ions and not positive ions or even ozone?

[237SJ]

Are you talking about the ionisers which became popular in the 80s? They used to say that you could tell the thing was working because it would draw dust towards it which would settle around. I never noticed anything like that with mine though.

[scotman]

A long time ago I had one which was just an ioniser. Dust did settle out round it. I now have(and would always recommend) getting an ioniser and filter combination. Works much better.

[Hypognosis]

I reckon that, if you tried that old trick with the plastic comb, rubbed on a woolen garment and then used to pick up a fragment of paper, if you hold this in the stream of ions from the de-ioniser, it should cause the piece of paper to fall off the comb.

My reasoning being that electrons rub off the plastic comb, leaving it positively charged. Electrons from the de-ioniser should restore it to neutrally charged.

Not a perfect answer by any means. You need to know the type of plastic the comb is made of and some plastics take on a negative electrostatic charge when rubbed on wool.