• Dew is the moisture that forms as a result of condensation. Condensation is  the process a material undergoes as it changes from a gas to a liquid. Dew is the result of water changing from a vapor to a liquid.
    Dew forms as temperatures drop and objects cool down. If the object becomes cool enough, the air around the object will also cool. Colder air is less able to hold water vapor than warm air. This forces water vapor in the air around cooling objects to condense. When condensation happens, small water droplets form—dew. 
    The temperature at which dew forms is called the dew point. The dew point varies widely, depending on location, weather, and time of day.
    Humid locations, such as the warm, coastal tropics, are more likely to experience dew than arid areas. Humidity measures the amount of water vapor in the air. Warm, humid air is full of moisture that can condense during calm, cool nights.
    Weather conditions can also influence an area's dew point. Strong winds, for instance, mix different layers of air, containing different amounts of water vapor. This reduces the atmosphere's ability to form dew.
    Cold weather can also prevent the formation of dew. As temperatures drop below freezing (0°Celsius, 32°Fahrenheit), a region may reach its frost point. At a frost point, water vapor does not condense. It sublimates, or changes directly from a gas to a solid. Moisture changes from water vapor to ice.
    Dew is most likely to form at night, as temperatures drop and objects cool. However, dew can form whenever a dew point is reached. 
    Although warm, humid areas commonly experience heavy dew, dew does not form in amounts people could to collect as a water source.
    Still, several organizations are working to develop technology that will allow them to harvest dew as a freshwater resource. They hope that foil condensers will help meet the water needs of arid areas. The most successful of these condensers have been put to work in Kutch, India, where hundreds of liters of water can be harvested every night at certain times of the year.
    Dew collects on a red rose.

    Dewy Eyes
    The water droplets that form on eyeglasses in hot, humid atmospheres is dew. However, the term "condensation," which applies to the process as well as the moisture itself, is usually used.

  • Term Part of Speech Definition Encyclopedic Entry
    arid Adjective


    condensation Noun

    process by which water vapor becomes liquid.

    Encyclopedic Entry: condensation
    condense Verb

    to turn from gas to liquid.

    condenser Noun

    tool to turn gas to liquid.

    dew Noun

    water droplets condensed from the atmosphere onto cool surfaces near the ground.

    Encyclopedic Entry: dew
    dew point Noun

    temperature at which water in the air condenses to form water droplets on objects near the ground.

    freshwater Noun

    water that is not salty.

    frost Noun

    thin coat of ice covering objects when the dew point is below freezing.

    Encyclopedic Entry: frost
    gas Noun

    state of matter with no fixed shape that will fill any container uniformly. Gas molecules are in constant, random motion.

    harvest Noun

    the gathering and collection of crops, including both plants and animals.

    humid Adjective

    air containing a large amount of water vapor.

    liquid Noun

    state of matter with no fixed shape and molecules that remain loosely bound with each other.

    moisture Noun


    sublimate Verb

    to change from a solid state to a gas state, without becoming liquid.

    technology Noun

    the science of using tools and complex machines to make human life easier or more profitable.

    temperature Noun

    degree of hotness or coldness measured by a thermometer with a numerical scale.

    Encyclopedic Entry: temperature
    tropics Plural Noun

    region generally located between the Tropic of Cancer (23 1/2 degrees north of the Equator) and the Tropic of Capricorn (23 1/2 degrees south of the Equator).

    Encyclopedic Entry: tropics
    vapor Noun

    visible liquid suspended in the air, such as fog.

    weather Noun

    state of the atmosphere, including temperature, atmospheric pressure, wind, humidity, precipitation, and cloudiness.

    Encyclopedic Entry: weather