On Wed, Feb 11, 2009, [email protected] said:
> where I disagree with one of the posts ( If I read it correctly ) is that I > believe that generally humidity goes DOWN with cold and UP with warmer air - Perhaps you are confusing what happens in experiemnets with observations of steady-states. Consider a large room, sufficiently sealed that we can experiment inside it. The amount of water vapor can be considered constant (well, it increases as the humans inside breath out moist air, make the room large enuogh and that can be neglected). If the air of the room is cooled, the capacity of the air to hold it decreases, and the relative humidity increases; cool it enough and you can make it rain inside the room. Stabilise the room as to both temperature and moisture content, with some pieces of wood present (they too are stabilized). Raise the temperature in the room and the air will have a greater capacity to hold moisture. The moisture in the wood will migrate to the air until the relative humiditys stabilize again. Central heating systems using forced hot air take in cold air from the outside, lower its RH by heating it, and dry out all the wood in the house (and the people) in the process. Sometimes there is a humidifier that adds water vapor to the hot air, more comomonly not. Arctic air is often pretty dry to begin with, making this the dryest of the seasons for most of us. > they only did their glue ups on tops during the later part of the summer > when they knew the humidity to be around 5 or so percent LOWER than the > typical humidity in which the instruments were to live. yes, very important. Some will have climate control in their shops, but not all can do that; historically one worked on various tasks as the seasons allowed. -- Dana Emery To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
