Just out of curiosity, can dust conduct electricity? The source of dust varies, is there any form of dust that can conduct electricity?
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2 Answers
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The answer to this question hinges on two key questions:
- What kind of dust are we dealing with?
- How is the dust arranged (i.e. what is your experimental setup)?
Which Dust?
Firstly, I'm going to assume you meant domestic dust (since there are more kinds of dust than you'd imagine).
I quote Wikipedia:
Dust in homes, offices, and other human environments contains small amounts of plant pollen, human and animal hairs, textile fibers, paper fibers, minerals from outdoor soil, human skin cells, burnt meteorite particles, and many other materials which may be found in the local environment.
Arrangement
The arrangement of the dust particles is key. Are we considering an aerosol, or are we carefully laying a line of dust on the table and connecting it with two electrodes?
Aerosol - We can safely assume that the conductance of air has a far higher impact on the measurement than the conductance of the particles in the aerosol (the dust). So here, dust does not conduct electricity. Note: I ignore the "conducting" via static electricity processes here, but they may play a role. I do not consider that "classical" conductance.
Line of Dust - Organic material is usually insulating, as is our skin (if it wasn't for the moisture that is needed for, you know, living), paper, textiles, hair and so on. So the main constituents of domestic dust does not conduct electricity. So also here, we will not observe conductance.
There is one exception to the above, where conductance is a possibility: Metal dust. This is kind of cheating, but consider the waste of some metalworking process, in which metal dust (or powder) is generated. This dust, being composed of metals and metal oxides, would likely conduct electricity (when laying it out in a line, still not as an aerosol).
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3$\begingroup$ An example I like involves space stations and vehicles in orbit. To write in space, an option would be to use pencils. However, when dragging a graphite tip across a surface, a small amount of graphite dust is released. Normally this fine dust settles quickly, but in space it keeps floating for a while. Though it may seem innocuous, the dust can eventually deposit on electronics, forming dangerous short-circuits as the graphite dust is electrically conductive. This is why pens must be used in space. $\endgroup$ Commented Mar 5, 2014 at 11:23
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Yes, dust can carry static charge. That's why people are cautious with dust on the inside of computers as they can short-circuit the electronics or inside.
Interestingly, dust particles in those huge grain silos; if given an ignition source - usually a spark - can produce such a large explosion that it blows off the rough of the silo.
While it wouldn't conduct full current flow per se; the suspended particles are able to carry electric charge and differences between the charges of the particles allows dust to have conductivity.
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1$\begingroup$ Isn't the main problem with dust inside computers that it clogs fanblades (restricting their motion) and heatsinks (reducing their effective surface)? $\endgroup$ Commented Mar 5, 2014 at 10:03
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$\begingroup$ @KlausWarzecha That's one reason. I was reading up on other forms, that if dust goes inside, i.e. once you open it, the static electricity discharges creating a large enough charge difference to short circuit some electronic components. I believe that this is exacerbated with more expensive electronic components. $\endgroup$– user3735Commented Mar 5, 2014 at 12:44