Nitpick: Hydrometers measure the specific gravity of liquids and are mostly used for beverages such as to calculate a liquid's sugar or alcohol contents. You'r

Nitpick: Hydrometers measure the specific gravity of liquids and are mostly used for beverages such as to calculate a liquid's sugar or alcohol contents. You're thinking of hygrometers, which measure relative humidity using capacitive, resistive, or gravimetric methods.