--- On Fri 06/10, William Beaty < [EMAIL PROTECTED] > wrote: > On Tue, 7 Jun 2005, Frederick Sparber wrote:
>> Why is this interesting? >> http://www-methods.ch.cam.ac.uk/meth/ms/theory/esi.html. > Also, electrospray may explain an electrostatic anomaly noticed by Michael > Foster: the air blast from a blow-dryer directed thru PVC pipe w/wet inner > surface creates strong charging. Also the PVC pipe had a slight coat of > algae from spending time in his swimming pool. Maybe the algae did > something weird, or maybe it just supported a water film which normally > couldn't exist (water would just bead up on the plastic.) The inside of the PVC pipes I used for this was definitely water wettable, rather than the expected water beading on the surface. The reason for this could be a number of things. The surface tension of plastics can be modified all sorts of ways. However, I finally figured out where the charge came from in this experiment, and unfortunately it wasn't charge by evaporation. I was just too dumb to figure it out until recently. I had wondered why I couldn't reproduce the result. And, of course, the reason is because I didn't repeat the experiment exactly. The first time I got a really crackling good charge when drying the interior of the PVC pipe, I had dryed the exterior of the pipe by wiping it off with a paper towel. No detectable charge was created by doing this because the interior of the pipe was still wet. Simply put, a rather substantial electrostatic charge had been created by rubbing, but was undetectable because of the conductive layer of water on the inside. In other words, the charge was there, but was held at a relatively low voltage. Lotsa coulombs, no volts. So by drying the interior of the PVC pipe with forced hot air, I had removed the conductive layer of water, thereby allowing the voltage to rise to several tens of kilovolts. Mildly interesting, but no new principle:( However, I have had a number of successful charge-by-evaporation experiments. These did not involve water or other polar solvents, which I have not yet been been able to make work. I have used a non-polar alkane hydrocarbon which has been heat evaporated to make and transport an electrostatic charge. There was no spray involved here, merely evaporation and condensation. As far as I can tell, this is a simple triboelectric phenomenon, which I can describe in detail if anyone is interested. Nevertheless, it is a heat pipe electric generator. Keep in mind, the Armstrong and subsequent Faraday experiments involved high pressure steam and fairly high heat. One can assume that at least partial condensation into water droplets was necessary to effect a charge transport. On the other hand, the setup I use can be driven by a fairly low heat difference. Whether anything useful can be made of this is open to question. M. _______________________________________________ Join Excite! - http://www.excite.com The most personalized portal on the Web!
