Download water in the atm notes

Name _______________________________________
Period _________
Water in the Atmosphere NOTES
Phase Changes of Water Graph:
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Important: A sample of water _______ ______ change temperature until all of it has gained or
released enough energy to completely change phases. After it has changed phases temperature will
change.
 Example: The temperature of an ice cube will stay at 0° (freezing) until the whole thing has
melted, then when it is all liquid it will change temperature.
 On the graph (above) this is represented by the _________ lines.
What did we learn from the heating soil/water experiment?
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___________ heats up and cools down faster because it has a _________ specific heat than ________.
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Specific Heat: amount of heat energy required to raise the ____________________ of ____ gram of a
material ______ degree Celsius.
 WATER HAS THE ____________ SPECIFIC HEAT CAPACITY OF ALL NATURALLY OCCURRING
MATERIALS ON EARTH.
How does this relate to weather?
 Temperatures near a large body of water like the ocean will be more ______________
(meaning cooler summers and warmer winters).
 It can create local areas of high and low pressure and therefore wind:
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Land and Sea breezes: examples of simple ___________________ _______________.
How does water get into the atmosphere?
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Two ways, one word EVAPOTRANSPIRATION:
o Evaporation: liquid water changes to the invisible gas ________ _________ due to energy input
(heating)
o Transpiration: water given off by __________.
Rate of evaporation depends on:
o ____________________
o ____________________
o ____________________
o ____________________(how much moisture is already in the air)
What does it mean when the relative humidity is high and it feels “sticky”?
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Vocabulary to know:
o Humidity: the amount of __________ ___________ in the air.
o Dewpoint (DP): the temperature at which the air is _________________, meaning it is holding
as much water vapor as possible.
 The only way to change dewpoint temperature is to add or take _____________ from
the air.
 Instrument used for measurement: __________ _____________________ NOTE: The
wet bulb is ALWAYS COLDER due to ____________________.
 Units used for measurement: _________ (usually Celsius)
o Relative Humidity(RH): the percent of ________________ of the air, comparing ACTUAL water
vapor in the air to POTENTIAL (air’s capacity) at that temperature.
 Ranges from ____ to ______. Closer to 100% means the air is closer to holding as much
water vapor as it can.
 Low RH means ____, ________ and ____________ conditions.
 High RH means ______ or ____________ conditions.
 Instrument used for measurement: __________ _______________________
 Units used for measurement: ___
Dewpoint and Relative Humidity are directly related. When the Relative Humidity reaches _____, you
have reached the _____________ and that means clouds, dew, fog or any other condensation will
form because the air can’t take in any more water vapor.
In the summer, why does the weather man say the RH is only 70% but it feels like I’m taking a bath in
the air?
o Warm air can hold ______ moisture than cold air, because as air is heated it __________ and
becomes less dense. RELATIONSHIP: increasing temperature, decreases RH, while DP stays the
same. So you can have a lot of moisture in the air on a hot day but not even be close to “filling it
up”.
 To understand this relationship you can think of RH as a fraction of Actual/Potential
(A/P).
 Example: Day One: The air is 70°F and is actually holding 5 grams of water vapor but has
the potential to hold 10 grams of water vapor at that temperature. Day Two: The air is
80° F and is still actually holding 5 grams of water vapor has the potential to hold 20
grams of water vapor at that temperature.
Day One: 70°F
Day Two: 80°F
RH= A/P = 5/10 = 50%
RH= A/P = 5/20 = 25%
How do you make clouds?
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Two main ingredients:
o Air cooled to the ____________ temperature
o __________________ ____________
What are condensation nuclei and why do you need them to make a cloud?
o Tiny particles in the air (dust, salt, pollen, dandruff, etc.)
o When water vapor condenses (changes to ________) that liquid water needs something to be
liquid on.
o So, clouds are actually little tiny droplets of _________ water (or sometimes ice) suspended in a
clump in the sky.
How do you cool air to the dewpoint temperature?
o Get it to __________
o How do you get air to rise? __________ it! Heated air ___________, becomes _______ dense
and less dense things rise (and more dense air rushing in underneath it to replace it helps to
push it up too)!
Basic steps: 1. __________ air
2. Air __________ and becomes _________ dense
3. Air _________ and cools to the ______________
4. When air reaches the ____________ temperature, _______________ occurs onto
_________________ _____________. IF there are no condensation nuclei present
there will be no condensation and no cloud! 
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Types of condensation: ________________________________________________________
Why don’t clouds fall out of the sky?
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The same reason other little particles are floating around in the air, the wind is keeping them up there,
which is easy to do because they are so tiny.
However, sometimes they do! When millions of cloud droplets get together and get heavy enough to
fall from the cloud, we call them _______________________.
Types of precipitation:
o ____________: ice crystals that remain _________ all the way to the ground.
o ____________: snow melts or liquids remain ____________ all the way to the ground.
o ___________: Rain ___________ on its way to the ground.
o _____________ _______: Rain ___________ once it hits the frozen ground.
o _________: Rain/ice __________ through a storm cloud growing larger.