Any amateur meteorologists here? I noticed an odd phenomenon in my home recently, and I can't come up with any ideas to explain it.
The air in my home was too dry, so I finally went and bought a couple warm mist humidifiers at Home Depot, and put them near the air-intake of the forced air gas furnace in my home. The humidifiers had a digital readout and read 15-20% when I first turned them on. Since then, over several days (and a lot of tank refills) they have gradually crept up to 50-55% when the furnace is not sucking air through the intake, and about 30-35% when the furnace is sucking air. (Apparently their is a humidity gradient near the humidifiers, which is not surprising I guess) What I can't explain is this: Despite not changing the thermostat setting on my furnace (it is a timer, turns down to 60F at night and back up to 68F just before I wake in the morning), I have noticed a huge change in whether the bathroom mirror gets fogged up when I take a hot shower in the morning. Pre-humidifiers, the mirror would always fog up very badly so that it had to be wiped off for use after my shower. After one day of the humidifiers, it seemed to me that the mirror wasn't fogging as much, but I wasn't sure. But this morning, after 3 days of humidifiers running constantly, THE MIRROR DID NOT FOG AT ALL during my hot shower. According to my calculations, the dewpoint for 68F air at 20% relative humidity is 26F, and for 68F air at 50% relative humidity the dewpoint is 49F. The mirror is probably somewhere between 60F and 68F (overnight the mirror should cool to about 60F and then start to warm up to 68F when the timer of the furnace kicks in). So in neither case should water condense on the mirror, BUT IT SHOULD BE "CLOSER" TO CONDENSING WITH THE HIGHER HUMIDITY THAN THE LOW. But I have observed the opposite. Evidently dewpoint does not explain the mirror fogging. Any ideas what principles are at work here? _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
