To determine the humidity using the hygrometer. This device can be of different types, is Extremely simple and widely used hair hygrometer. Long thread one end is fixed on the shaft, the other end is stretched and attached to the housing. The thread can stretch, which increases the humidity, and decreased when the air is dry. When this roller mounted on it the arrow is in motion, and on a scale you can determine what is the humidity.
Another simple hygrometer consists of two thermometers. Bulb with mercury one of them wrapped in wet gauze. If the humidity reaches 100%, the readings of both thermometers are equal, if it is lower, the water from Marley begins to evaporate and cool the mercury. Comparing the readings of the thermometers, you can determine the humidity, It is expressed in percentage. This is called relative humidity. For example, if the relative humidity 40% - this means that the air contains 40% water vapor, which may be withheld them at this temperature for Not less than 40% humidity should be in a residential installation. When humidity is close to 100%, water molecules begin to stick together and can form droplets.
Humidity is measured using two thermometers.
The greater the temperature difference, the less humidity.