What is Humidity?
Humidity, water vapor, moisture, steam. They’re all the same. They are one form of water. Humidity is an invisible gas. It is present in varying quantities in nearly all air. THIS MOISTURE IN WET AIR TRIES TO FLOW TOWARD DRIER AIR AND MIX WITH IT. Scientists describe this force as “vapor pressure.” It is often a very powerful force indeed. It can act independently of the flow of the air which holds the moisture. Vapor pressure can force moisture easily through wood, plaster, brick, cement… right through most of the materials we use to build our homes. That is exactly what happens when moisture seeks to escape from the humid air usually found inside your home to the drier winter air outside. “MORE Moisture Trapped in LESS Space” Certain building materials stop water vapor. Glass is one of these. Also on this list are some varnishes, paints, tiles, plastic wall coverings. Vapor-seal insulation is designed specifically to stop the escape of water vapor and protect the insulation and you
Humidity is the amount of moisture in the air. It can be measured in various ways, but the most usual is to describe it as ‘relative’ humidity. This is expressed as a percentage. A relative humidity of 100% means the moisture content of the air is the maximum possible at any particular temperature. The hotter the air, the more moisture it can hold. Why is it Important? When relative humidity is low, evaporation is rapid. Soil dries out, wet clothes dry quickly and perspiration evaporates from the skin. When relative humidity is high, clothes dry slowly and body sweat cannot evaporate easily. We feel sticky and hot and because our perspiration cannot evaporate quickly, we feel uncomfortable. We can stand dry heat much better than damp heat which makes us feel listless and takes our energy away.
Ever wonder what determines humidity or makes rain fall from the sky? This time of year, these are good things to contemplate, according to George Taylor, the state climatologist of Oregon. “A good way to picture humidity is to think of air as a sponge,” said Taylor, who runs the Oregon Climate Service, affiliated with the Department of Oceanic and Atmospheric Science at Oregon State University. “Both air and a sponge hold water. A sponge holds liquid, while the air holds water vapor. Both can be quite full of water, or saturated.” The air’s capacity to hold water in the form of water vapor increases as temperature increases. “The air ‘sponge’ gets bigger when temperatures go up,” he explained. “If the air is holding as much water as it possibly can, the relative humidity is 100 percent.” “Relative humidity” is a term meteorologists use to describe the actual amount of water in the air compared with the maximum amount it could hold at a given temperature, said Taylor. At different temp
