Atmospheric humidity. Saturated vapor and psychrometer – hygrometer
The online atmospheric humidity simulations on this page are a very useful tool to deepen in this concept and to know its measuring instruments, the psychrometer – hygrometer. You will also learn what we mean when we talk about saturated steam and, in particular, saturated water vapor.
This Thematic Unit is part of our Earth Sciences collection
STEM OnLine mini dictionary
Atmospheric Humidity
Amount of water vapor present in the air, originating from the evaporation of water bodies and biological transpiration.
Condensation
Change of state from water vapor to liquid that occurs when air cools below its dew point.
Dew Point
Specific temperature to which an air mass must be cooled to reach saturation and begin condensation.
Hygrometer
Precision instrument designed to measure the moisture content in the atmosphere.
Relative Humidity
Percent relationship (%) between the current water vapor and the maximum the air could hold before becoming saturated.
Saturated Air
State in which the air contains the maximum possible amount of water vapor for a given temperature (100% relative humidity).
Water Vapor
Water in a gaseous state that mixes with the air; it is the main driver of cloud formation and meteorological phenomena.
What is atmospheric humidity
Atmospheric humidity is the amount of water vapor present in the air. It is an essential component of the atmosphere and plays a critical role in climate, meteorology and human well-being. Atmospheric humidity is commonly measured using two main concepts: relative humidity and absolute humidity.
Types of atmospheric humidity: absolute humidity and relative humidity
Absolute humidity is a direct measure of the actual amount of water vapor in the air, usually expressed in grams per cubic meter or grams per kilogram. It can be determined using instruments such as hygrometers or using equations that consider air temperature and pressure.
Relative humidity is a measure of how much moisture is in the air compared to the maximum amount the air can hold at a specific temperature and pressure. It is expressed as a percentage and is calculated by dividing the current vapor pressure by the maximum vapor pressure at that temperature. A relative humidity of 100% means that the air is saturated and can hold no more water vapor.
Effects of atmospheric humidity
Atmospheric humidity has several effects on the climate and the environment. For example, high humidity can make the air feel heavier and warmer, as water vapor retains and transfers heat more efficiently than dry air. In addition, high humidity can influence cloud formation and precipitation, as water vapor condenses to form water droplets or ice crystals.
Atmospheric humidity affects our perception of temperature through the heat index. Atmospheric humidity is also important for agriculture, as it affects the ability of the air to support plant life and crop growth.
STEM OnLine mini dictionary
Atmospheric Humidity
Amount of water vapor present in the air, originating from the evaporation of water bodies and biological transpiration.
Condensation
Change of state from water vapor to liquid that occurs when air cools below its dew point.
Dew Point
Specific temperature to which an air mass must be cooled to reach saturation and begin condensation.
Hygrometer
Precision instrument designed to measure the moisture content in the atmosphere.
Relative Humidity
Percent relationship (%) between the current water vapor and the maximum the air could hold before becoming saturated.
Saturated Air
State in which the air contains the maximum possible amount of water vapor for a given temperature (100% relative humidity).
Water Vapor
Water in a gaseous state that mixes with the air; it is the main driver of cloud formation and meteorological phenomena.
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Atmospheric humidity simulations
Psychrometer – hygrometer
A psychrometer is a simple device that allows you to determine the humidity by measuring the difference in how much water evaporates. The wet-bulb hygrometer consists of two thermometers, a dry-bulb, and a wet-bulb. Humidity is measured using the temperature difference between the two thermometers.
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Test your knowledge
What is atmospheric humidity, and why is it essential in meteorology and climate studies?
How are absolute humidity, relative humidity and temperature related in atmospheric behavior?
What is humidity in simple terms?
What is the difference between absolute and relative humidity?
Why does humidity make hot days feel hotter?
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