How does a Hygrometer work?
Contributed by guest writer Jenni Worboys What is a Hygrometer? A hygrometer is an easy to use tool for measuring the amount of humidity in the atmosphere. There are two main types of hygrometers – a dry and wet bulb psychrometer and a mechanical hygrometer. What is Humidity? Humidity is the amount of water vapor in the atmosphere caused by condensation and evaporation. It can be measured as absolute humidity (the amount of water vapor in a unit volume of air), or as relative humidity (the ratio of moisture in the atmosphere to the maximum moisture the atmosphere can hold). It is what gives you that horrible sticky feeling on a hot day and can cause heat stroke. We feel most comfortable with relative humidity between 30% and 60%. How do Hygrometers Work? Wet and dry bulb psychrometers are the most simple and common way of measuring humidity. This type of hygrometer uses two basic mercury thermometers, one with
