Chapter 23 Chapter 23 Section 1 Section 1 HandoutHandoutAtmospheric Atmospheric

MoistureMoisture

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The states in which water The states in which water exists in the atmosphere exists in the atmosphere are called:are called:PhasesPhases

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When does water change When does water change from one phase to another?from one phase to another?When heat energy is When heat energy is absorbed or releasedabsorbed or released

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What phase does ice change What phase does ice change into when it absorbs energy?into when it absorbs energy?liquidliquid

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When liquid water absorbs When liquid water absorbs energy, it changes to:energy, it changes to:A gasA gas

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What happens to the water What happens to the water molecules when the water molecules when the water absorbs energy?absorbs energy?They collide more They collide more frequentlyfrequently

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The process in which the The process in which the fastest-moving molecules fastest-moving molecules escape from liquid and form escape from liquid and form invisible water is calledinvisible water is calledevaporationevaporation

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The name for heat energy The name for heat energy that is absorbed or released that is absorbed or released during a phase change is:during a phase change is:latent heatlatent heat

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When liquid water When liquid water evaporates, the water:evaporates, the water:absorbs energy from the absorbs energy from the environmentenvironment

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The name for the process in The name for the process in which water vapor changes which water vapor changes back into a liquid is:back into a liquid is:condensationcondensation

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Through what process does Through what process does most water enter the most water enter the atmosphere?atmosphere?evaporationevaporation

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Where on Earth does most Where on Earth does most evaporation take place?evaporation take place?In the oceans of the In the oceans of the equatorial regionsequatorial regions

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What is the name of the What is the name of the process in which a solid process in which a solid changes directly into a gas?changes directly into a gas?SublimationSublimation

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Under what conditions might Under what conditions might sublimation of snow and ice sublimation of snow and ice occur?occur?When the air is dry and the When the air is dry and the temperature is below temperature is below freezingfreezing

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HumidityHumidityWater vapor in the Water vapor in the atmosphereatmosphere

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Dew pointDew pointThe temperature at which The temperature at which condensation equals condensation equals evaporationevaporation

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Absolute humidityAbsolute humidityThe mass of water vapor The mass of water vapor contained in a given volume contained in a given volume or airor air

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Mixing ratioMixing ratioThe mass of water vapor in The mass of water vapor in a unit of air relative to the a unit of air relative to the mass of the dry airmass of the dry air

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What controls humidity?What controls humidity?Rates of condensation and Rates of condensation and evaporationevaporation

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What determines the rate of What determines the rate of evaporation?evaporation?Air temperatureAir temperature

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What happens to the rate of What happens to the rate of evaporation as the evaporation as the temperature gets higher?temperature gets higher?It also gets higherIt also gets higher

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The measure of the actual The measure of the actual amount of water vapor in the amount of water vapor in the air is called the:air is called the:absolute humidityabsolute humidity

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The ratio of the The ratio of the actual water vapor actual water vapor content of the air content of the air to the amount of to the amount of water vapor water vapor needed to reach needed to reach saturation is saturation is called:called: Relative Relative

humidityhumidity

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If a person wanted to know If a person wanted to know how close the air is to how close the air is to reaching the dew point, he or reaching the dew point, he or she would calculate the:she would calculate the:Relative humidityRelative humidity

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What can make the relative What can make the relative humidity change even if the humidity change even if the temperature does not temperature does not change?change?Moisture entering the airMoisture entering the air

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What can make the relative What can make the relative humidity increase if the humidity increase if the moisture in the air remains moisture in the air remains the same?the same?A decrease in the A decrease in the temperaturetemperature

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What happens to the relative What happens to the relative humidity if the temperature humidity if the temperature increases as the moisture in increases as the moisture in the air remains constant?the air remains constant?The relative humidity will The relative humidity will decreasedecrease

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What is the name of the What is the name of the condensation that forms condensation that forms during night?during night?dewdew

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What causes dew to form?What causes dew to form?Objects near the ground lose Objects near the ground lose heat during the night, often heat during the night, often dropping to the dew point of dropping to the dew point of the surrounding air. Air the surrounding air. Air comes in contact with the comes in contact with the surfaces and water vapor surfaces and water vapor condenses out of it.condenses out of it.

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PsychrometerPsychrometerAn instrument used to An instrument used to measure relative humidity measure relative humidity consisting of two identical consisting of two identical thermometer.thermometer.

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What is the difference between What is the difference between the two thermometers of a the two thermometers of a psychrometer?psychrometer?The bulb of one is covered The bulb of one is covered with a damp wick and the with a damp wick and the bulb of the other remains drybulb of the other remains dry

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What happens to the wet bulb-What happens to the wet bulb-thermometer when the thermometer when the psycrhormeter is whirled psycrhormeter is whirled through the air?through the air?The water in the wick The water in the wick evaporates, and so heat is evaporates, and so heat is withdrawn from the withdrawn from the thermometer.thermometer.

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How does the temperature of How does the temperature of the wet-bulb thermometer differ the wet-bulb thermometer differ from that of the dry-bulb from that of the dry-bulb thermometer after the thermometer after the psychrometer is whirled psychrometer is whirled through the air?through the air?The wet-bulb thermometer is The wet-bulb thermometer is lowerlower

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What would you use to What would you use to calculate the relative calculate the relative humidity from a humidity from a psychrometer?psychrometer?The difference between the The difference between the readings of the two readings of the two thermometers.thermometers.

The EndThe End