There are several types of hygrometers, each working on different principles:
* Hair hygrometer: This type uses the fact that human hair expands and contracts with changes in humidity.
* Psychrometer: This device uses two thermometers, one dry and one wet. The difference in their readings is used to calculate relative humidity.
* Capacitance hygrometer: This type measures the change in capacitance of a material (usually a polymer) as the humidity changes.
* Electronic hygrometer: These instruments use electronic sensors to measure humidity. They are often used in weather stations and homes.
So, the answer is yes, relative humidity can be measured with an instrument, and there are various types of instruments available for this purpose.
