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"LMS Ch 23.1 DR

"LMS Ch 23.1 Directed Reading

The states in which water exists in the atmosphere are called _______________ phases
The gas phase of water is called ____________________ water vapor
The solid phase of water is called ___________________ ice
The liquid phase of water is called _________________ water
When does water change from one phase to another? when heat energy is absorbed or released
When ice absorbs energy, the molecules of ice move more quickly.
What phase does ice change into when it absorbs energy? liquid
When liquid water absorbs energy, it changes to a gas.
What happens to the water molecules when the water absorbs energy? They collide more frequently.
The process in which the fastest-moving molecules escape from liquid and form invisible water is called evaporation.
The name for heat energy that is absorbed or released during a phase change is latent heat.
When liquid water evaporates, the water absorbs energy from the environment.
What happens to energy absorbed by water during evaporation? It becomes potential energy between water molecules.
The name for the process in which water vapor changes back into a liquid is condensation.
During the condensation of water, latent heat is released into the surrounding air.
What happens to latent heat when ice thaws? It is absorbed.
When water freezes, latent heat is released into the air.
Through what process does most water enter the atmosphere? evaporation
Where on Earth does most evaporation take place? in oceans of the equatorial regions
Name four other important sources of water vapor in the atmosphere. evaporation from lakes, ponds, streams, and soil
How are plants, volcanoes, and burning fuels related to water vapor in the atmosphere? They release small amounts of water vapor into the atmosphere.
What usually happens to ice before it changes into a gas? It changes into a liquid.
What is the name of the process in which a solid changes directly into a gas? sublimation
Under what conditions might sublimation of snow and ice occur? when the air is dry and the temperature is below freezing
Water vapor can turn directly into ice without becoming a(n) liquid
water vapor in the atmosphere humidity
the temperature at which condensation equals evaporation dew point
the mass of water vapor in a unit of air relative to the mass of the dry air mixing ratio
the mass of water vapor contained in a given volume of air absolute humidity
What controls humidity? rates of condensation and evaporation
What determines the rate of evaporation? air temperature
What happens to the rate of evaporation as the temperature gets higher? It gets higher.
What determines the rate of condensation? vapor pressure
The part of the total atmospheric pressure that is caused by water vapor is vapor pressure
When there is equilibrium between the rate of evaporation and the rate of condensation, the air is ______________. saturated
The measure of the actual amount of water vapor in the air is called the__________________. absolute humidity
What equation is used to calculate the absolute humidity? absolute humidity
Why do meteorologists prefer to describe humidity by using the mixing ratio of air? because, as air moves, its volume changes as a result of temperature and pressure changes.
What is the mixing ratio of air that has 18 g of water vapor in 1 kg of air? 18 g/kg
What is a common mixing ratio for air in polar regions? less than 1 g/kg
Why is the mixing ratio not affected by changes in temperature or pressure? because the measurement uses only units of mass, not units of volume
The ratio of the actual water vapor content of the air to the amount of water vapor needed to reach saturation is called relative humidity
If a person wanted to know how close the air is to reaching the dew point, he or she would calculate the _______________ relative humidity
At what point does air become saturated at 25°C? when it contains 20 g of water vapor per 1 kg of air
How would you express the relative humidity of air that is 25°C and contains 5 g of water? 25%
What can make the relative humidity change even if the temperature does not change? moisture entering the air
What can make the relative humidity increase if the moisture in the air remains the same? a decrease in the temperature
What happens to the relative humidity if the temperature increases as the moisture in the air remains constant? The relative humidity will decrease.
What can cause air to cool to its dew point? conduction when the air is in contact with a cold surface
What is the name of the condensation that forms during the night? dew
What causes dew to form? Objects near the ground lose heat during the night, often dropping to the dew point of the surrounding air. Air comes into contact with the surfaces and water vapor condenses out of it.
Under what conditions is dew most likely to form? Cool clear nights with little wind
What is the form of condensation that forms if the dew point falls below the freezing temperature of water? frost
What is the difference between frost and frozen dew? Frost forms when water vapor turns directly to ice; frozen dew forms when dew freezes as clear beads of ice.
an instrument used to measure humidity consisting of a heater and two electrodes dew cell
the ability to conduct electricity electrical conductance
an instrument used to measure relative humidity consisting of two identical thermometers psychrometer
Why do meteorologists measure humidity? It helps them predict weather conditions.
What happens when the lithium chloride in a dew cell absorbs water from the air? Its electrical conductance increases.
What happens as the water evaporates from the LiCl? The LiCl loses its ability to conduct electricity.
The temperature at which the LiCl in a dew cell loses its ability to conduct electricity is the .______________ dew point
What is the difference between the two thermometers of a psychrometer? The bulb of one is covered with a damp wick and the bulb of the other remains dry.
What happens to the wet bulb-thermometer when the psychrometer is whirled through the air? The water in the wick evaporates, and so heat is withdrawn from that thermometer.
How does the temperature of the wet-bulb thermometer differ from that of the dry-bulb thermometer after the psychrometer is whirled through the air? That of the wet-bulb thermometer is lower.
What would you use to calculate the relative humidity from a psychrometer? the difference between the readings of the two thermometers
What is a radiosonde ? a package that carries instruments into the atmosphere
What is an electric hygrometer? an instrument that measures humidity at high altitudes
an instrument that measures relative humidity by using a bundle of hairs hair hygrometer
As relative humidity increases, what happens to hair? It gets longer.
What is a disadvantage of using a hair hygrometer? It is less accurate than psychrometers and dew cells.
How does an electric hygrometer work ? An electric current is passed through a moisture-attracting substance. The amount of moisture changes the electrical conductivity of the substance and can be measured and expressed as relative humidity of the surrounding air.
Created by: tbfreema

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