ATS 350 Exam 2 Questions Answered Correctly Latest Update 2025-2026
Describe how molecular bonds regulate transitions of water vapor between solid, liquid, and gas
forms - Answers It takes energy to break bonds and making bonds releases energy. Water is
also unique because of its ability to H-bond
What does the air being saturated mean? - Answers The maximum amount of water vapor in the
air at equilibrium between evaporation and condensation -- i.e. the max amount of water vapor
that can exist in an air parcel at that temp
How does saturation vapor pressure depend upon temperature? - Answers As temperature
increases, saturation vapor pressure increases -- hotter air can hold more water.
How does saturation vapor pressure over liquid water and ice differ? - Answers The saturation
vapor pressure is higher over liquid than over ice
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - Saturation vapor pressure -
Answers max amount of water vapor that can exist in the air at equilibrium. Doesn't vary with
atmospheric water vapor content, but increases with air temp
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - vapor pressure - Answers the
pressure exerted by water vapor molecules in the air. Increases with more water vapor content,
increases with temp (PV=nRT)
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - relative humidity - Answers
describes how far the air is from being saturated (actual vapor content / saturation vapor
pressure). Increasing the atmospheric water vapor content increases relative humidity (if temp
is held constant). Increasing the temperature increases saturation vapor pressure, decreasing
RH.
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - dew point temperature -
Answers the temperature at which the atmosphere would reach saturation without changing the
water vapor content. If you increase the atmospheric water vapor content, you increase
dewpoint. If you increase air temperature, doesn't do anything.
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - wet bulb temperature - Answers
the minimum temperature that can be reached by evaporating water into air -- the difference
between the wet bulb and dry bulb temperature can calculate RH and dewpoint.
Understand the following measures of humidity and how they change with atmospheric water
, vapor content and air temperature (the dry bulb temperature): - mixing ratio - Answers mass of
water vapor in an air parcel relative to mass of dry air in the parcel.
How do these different measures of humidity change when air parcels rise or fall? - Answers
When air parcels rise, the particles expand and become cooler and the dewpoint temperature
can be reached. And vice versa
Explain what happens to these measures of humidity when the air is saturated. - Answers RH is
100%, the air is at the dewpoint temp
Why is air typically more humid on the Gulf of Mexico Coast than in the Western U.S.? - Answers
The ocean is warm in the Gulf of Mexico but cool on the west coast. The air is saturated over
the cold water and moves over warm land that has a higher saturation pressure leading to lower
RH.
How is humidity measured? - Answers A Sling Psychrometer calculates RH and dwpoint
because it has a wet-bulb temp and a dry bulb
How does relative humidity change during the day? How do dew point, vapor pressure, and
saturation vapor pressure change during the day? - Answers RH can change during the day even
when the actual vapor pressure is constant. Tends to be higher at night when it's cooler temps
(closer to dewpoint) and lower during the day when it's warmer temps. Dewpoint temp is pretty
constant during the day.
How do different measures of humidity change from indoors to outdoors? - Answers In the
winter, RH can decrease dramatically inside because the temp is raised
What are frost and dew, and under what conditions do they form? - Answers Dew forms when
the temp of the surface air drops to the dewpoint temp (100% RH) resulting in condensation on
the surface. Frost forms when the temp of the surface air drops to the dewpoint and is below
freezing
What is advection fog? - Answers Warm moist air moves over a cold surface, the transfer of
heat cools the air to its dewpoint
What is upslope fog? - Answers Moist air flows up a hill and cools as it rises
What is mixing fog? - Answers Moist air from your mouth or nose meets cold air and saturates it
What is radiation fog? - Answers Forms from Earth's radiational cooling during clear nights.
Surface inversion, cold air, saturation
What role do cloud condensation nuclei (CCN) play in cloud and fog formation? - Answers
Provide a seed on which droplets can form
cirrus clouds - Answers high cloud, thin and wispy, ice crystals
Describe how molecular bonds regulate transitions of water vapor between solid, liquid, and gas
forms - Answers It takes energy to break bonds and making bonds releases energy. Water is
also unique because of its ability to H-bond
What does the air being saturated mean? - Answers The maximum amount of water vapor in the
air at equilibrium between evaporation and condensation -- i.e. the max amount of water vapor
that can exist in an air parcel at that temp
How does saturation vapor pressure depend upon temperature? - Answers As temperature
increases, saturation vapor pressure increases -- hotter air can hold more water.
How does saturation vapor pressure over liquid water and ice differ? - Answers The saturation
vapor pressure is higher over liquid than over ice
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - Saturation vapor pressure -
Answers max amount of water vapor that can exist in the air at equilibrium. Doesn't vary with
atmospheric water vapor content, but increases with air temp
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - vapor pressure - Answers the
pressure exerted by water vapor molecules in the air. Increases with more water vapor content,
increases with temp (PV=nRT)
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - relative humidity - Answers
describes how far the air is from being saturated (actual vapor content / saturation vapor
pressure). Increasing the atmospheric water vapor content increases relative humidity (if temp
is held constant). Increasing the temperature increases saturation vapor pressure, decreasing
RH.
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - dew point temperature -
Answers the temperature at which the atmosphere would reach saturation without changing the
water vapor content. If you increase the atmospheric water vapor content, you increase
dewpoint. If you increase air temperature, doesn't do anything.
Understand the following measures of humidity and how they change with atmospheric water
vapor content and air temperature (the dry bulb temperature): - wet bulb temperature - Answers
the minimum temperature that can be reached by evaporating water into air -- the difference
between the wet bulb and dry bulb temperature can calculate RH and dewpoint.
Understand the following measures of humidity and how they change with atmospheric water
, vapor content and air temperature (the dry bulb temperature): - mixing ratio - Answers mass of
water vapor in an air parcel relative to mass of dry air in the parcel.
How do these different measures of humidity change when air parcels rise or fall? - Answers
When air parcels rise, the particles expand and become cooler and the dewpoint temperature
can be reached. And vice versa
Explain what happens to these measures of humidity when the air is saturated. - Answers RH is
100%, the air is at the dewpoint temp
Why is air typically more humid on the Gulf of Mexico Coast than in the Western U.S.? - Answers
The ocean is warm in the Gulf of Mexico but cool on the west coast. The air is saturated over
the cold water and moves over warm land that has a higher saturation pressure leading to lower
RH.
How is humidity measured? - Answers A Sling Psychrometer calculates RH and dwpoint
because it has a wet-bulb temp and a dry bulb
How does relative humidity change during the day? How do dew point, vapor pressure, and
saturation vapor pressure change during the day? - Answers RH can change during the day even
when the actual vapor pressure is constant. Tends to be higher at night when it's cooler temps
(closer to dewpoint) and lower during the day when it's warmer temps. Dewpoint temp is pretty
constant during the day.
How do different measures of humidity change from indoors to outdoors? - Answers In the
winter, RH can decrease dramatically inside because the temp is raised
What are frost and dew, and under what conditions do they form? - Answers Dew forms when
the temp of the surface air drops to the dewpoint temp (100% RH) resulting in condensation on
the surface. Frost forms when the temp of the surface air drops to the dewpoint and is below
freezing
What is advection fog? - Answers Warm moist air moves over a cold surface, the transfer of
heat cools the air to its dewpoint
What is upslope fog? - Answers Moist air flows up a hill and cools as it rises
What is mixing fog? - Answers Moist air from your mouth or nose meets cold air and saturates it
What is radiation fog? - Answers Forms from Earth's radiational cooling during clear nights.
Surface inversion, cold air, saturation
What role do cloud condensation nuclei (CCN) play in cloud and fog formation? - Answers
Provide a seed on which droplets can form
cirrus clouds - Answers high cloud, thin and wispy, ice crystals
