The question of measurement of humidity concerns not only physicists, but also weather forecasters. And us – ordinary people it has to interest too, especially in case we spend a lot of time in rooms. The excessive humidity makes an adverse effect not only on the person, but also on the apartment in general. For this reason the humidity needs to be controlled. There are several ways of measurement of humidity in rooms.
It is required to you
- hygrometer or psychrometer.
Instruction
1. The principle of action of hygrometers consists in the analysis of influence of humidity on certain matter. For example, the hair hygrometer uses surprising feature of a human hair – to change length under the influence of humidity of air. Such method allows to measure humidity ranging from 30% up to 100%. In a film hygrometer other sensitive element – an organic film is used. However these types of hygrometers are less exact, than psychrometers, but in winter time they are the main devices by means of which the humidity is measured. Besides above-mentioned, there are some more types of hygrometers: weight, ceramic, electrolytic, condensation.
2. The psychometric way of determination of humidity indoors is quite popular. When using hygrometers there is a deviation approximately in 5%, but using the psychrometer, you receive absolutely exact result. The psychrometer consists of two thermal sensors: one of them damp, another - dry. The humidity of the sensor is reached because it is wound with wet cotton fabric. Moisture evaporates and as a result cools the thermometer. At the same time other sensor fixes exact air temperature indoors. The obtained data are transferred to the microprocessor which measures relative air humidity.
3. But what to do if you have neither psychrometer, nor a hygrometer? It is possible to learn approximate value of humidity indoors also in easier way. Pour cold water into a small glass, then put it in the fridge at several o'clock, so that water was cooled up to 3–5 degrees. Having taken the cooled glass from the fridge, place it in the room in which it is necessary to measure humidity of air, and glass with water needs to be put as it is possible further from heating devices. Within several minutes watch the surface of glass: - if glass walls at first misted over, and in five minutes became dry, then it means that air in dry; - if the surface and remained misted over, then indoors moderate humidity; - the high humidity is demonstrated by the formed water streamlets on glass walls.