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Quiz Chapter 24
1. Sublimation
2. Latent heat
3. Humidity
4. Saturated
5. Relative humidity
6. Psychrometer
7. Hair hygrometer
8. Specific humidity
9. Dew point
10.Dew
Turn to
page 482
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describe how relative humidity is
measured
This is due at the end of class
Warm up question: How does relative humidity
measure humidity
Exit: What is a dew point
Homework: Questions on page 483 – due 2/4
Essential Question
Describe what happens when the
temperature of air decreases at
or below the dew point
Homework
Questions on page 483 – due 2/4
.
Chapter 24
1. Sublimation
12.Condensation nuclei
2. Latent heat
13.Convective cooling
3. Humidity
14.Adiabatic
4. Saturated
15.Advective cooling
5. Relative humidity
16.Stratus clouds
6. Psychrometer
17.Cumulus clouds
7. Hair hygrometer
18.Cirrus clouds
8. Specific humidity
19.Radiation fog
9. Dew point
20.Advection fog
10.Dew
21.Upslope fog
11.Frost
22.Steam fog
Chapter 24
23.Sleet
24.Glaze ice
25.Hail
26.Coalescence
27.Supercooling
28.Freezing nuclei
29.Cloud seeding
30.Rain gauge
• Video Link
• experiments
Chapter 24 Section 1 Objectives
• Explain how water vapor enters the air.
• Explain the meaning of humidity and
describe how it is measured.
• Describe what happens when the
temperature of air decreases at or below
the dew point.
Notes chapter 24 section 1
• Atmospheric Moisture
• Water in the air is
•
called water vapor: it
is tasteless, odorless,
and invisible gas
Water in the air can
also be in the form of
ice or water droplets
Notes chapter 24 section 1
• Heat energy and water
• Water in the form of ice is
•
•
held in a CRYSTALLINE
STRUCTURE
Evaporation occurs when
water molecules rotate and
vibrate fast enough to
overcome forces of attraction
Can ice become vapor
without first becoming
water?
– Sublimation: process where
water in a solid form (ice) goes
directly to a gas phase
Notes chapter 24 section 1
• Heat energy and water
• Though most water enters
atmosphere through
EVAPORATION, some water
does enter through
SUBLIMATION
– Where does most sublimation
occur? (hint: where is there a
lot of ice???)
• Latent Heat: “Hidden” heat
– Given off during evaporation
– Taken out during freezing
Notes chapter 24 section 1
• Humidity
• Humidity: amount of water in
the atmosphere
– When the air CANNOT hold
anymore water, the air is
considered to be SATURATED
• The higher the temperature
of air – THE MORE WATER
IT CAN HOLD
– As the temperature decreases,
so does the ability of air to hold
water vapor
Notes chapter 24 section 1
• Relative Humidity
• Relative Humidity is a
RATIO
MASS OF WATER IN AIR
POTENTIAL MASS OF WATER
• Potential mass of water that
air can hold changes with the
temperature of the air
– Hotter - more water vapor
content
– Colder – less water vapor
content
Notes chapter 24 section 1
• Measuring Relative
Humidity
• Wet Bulb – Dry Bulb
Method
– Dry bulb takes temperature of
air with the amount of moisture
present
– Wet Bulb takes temperature of
air SIMULATING A SATURATED
ATMOSPHERE
– Using both measurements,
estimate humidity based on
Relative Humidity Chart
• Tool: PSYCHOMETER
Notes chapter 24 section 1
• Specific Humidity
• Express the amount
•
of water in the air in
g/kg
It is not affected by
temperature or
pressure.
Notes chapter 24 section 1
• Dew point
• This is the temperature
•
•
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at which air is saturated
with water . Below this
temperature liquid or
solid water forms.
Dew may also form on a
surface via condensation
If the dew point is below
freezing frost will form
list the conditions that must exist
for a cloud to form
Chapter 24 Section 2 Objectives
• List the conditions that must exist for a
cloud to form.
• Identify the types of clouds.
• Describe four ways fog may form.
Notes chapter 24 section 2
• Clouds and fog
• Are visible water
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droplets in the
atmosphere
Clouds and fog are
the same, altitude is
the only difference.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Cloud formation
• The water needs
•
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something to
condense onto, dust.
The air must be at or
below the dew point
to cause cloud
formation or
saturated.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Convective cooling
• As air rises it expands
•
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and cools, due to the
release of energy.
This process of
cooling and heating to
rising and falling air is
called adiabatic
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Convective cooling
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• Warms at a steady
rate of 10C for every
100 M the air
descends. The cooling
is effected by the
condensation process
and averages .70C per
100 M the air rises.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Convective cooling
• The level at which the
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clouds form is called
the condensation
level.
This starts at the
bottom of the cloud
and further
condensation allow
the clouds to form up.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Forceful Lifting
• Can be caused by air
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moving over a
mountain range.
It can also be caused
by warm air pushing
over a cold air mass.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Temperature changes • The mixing of two or
more moist air
masses with different
air temperatures may
be enough to get
below the dew point.
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list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Advective cooling
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• This is when warm
moist air passes over
a cold body of water
or land mass, the
heat is absorbed
(dropping below the
dew point) and low
clouds form or fog.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Classification of
clouds
• By form and altitude
• Forms: Stratus,
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Cumulus and Cirrus.
Altitude groups: Low
is up to 2,000 M,
Middle is 2,000 to
6,000 M and High is
above 6,000 M
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Are sheet like or layered, they
• Stratus Clouds
•
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are low to the earth surface
and cover large areas of the
sky.
Formed when warm air is
above cool air, give very little
rain.
Two other types:
nimbostratus are dark and
give heavy rain or snow,
altostratus form at middle
latitudes and little rain
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Are the puffy or popcorn
• Cumulus Clouds
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clouds, if the form at the
middle they are altocumulus
and at lower levels are
stratocumulus and cumulus.
If there are strong rising
winds a cumulonimbus forms
and can produce thunder,
lighting and rain.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Cirrus Clouds
• These are the feathery or
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curly clouds at high
altitudes.
Normally made of ice
crystals, that can cause a
halo to form around the
sun or moon.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 2
• Fog
• Radiation fog or ground fog forms
•
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close to the ground as it gives off the
heat from the day, more common in
valleys were the cold air can collect.
Advection fog forms when warm moist
air pushes over a colder surface.
Upslope fog is cause by warm air
moving uphill and steam fog is when
warm air moves over a colder body of
water.
list the conditions that must exist
for a cloud to form
Chapter 24 section 3 essential
questions
• Describe the various types of liquid and
solid precipitation.
• Compare the two processes that cause
precipitation
• Describe how rain may be produced
artificially
• Describe how precipitation is measured
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list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Precipitation
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• Moisture that falls
from the sky; either
as a liquid or solid. (
rain, snow, sleet and
hail)
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Forms of precipitation • Liquid – rain
• A drizzle – drops less
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then .5 mm are close
together and fall
slowly.
Raindrops - .5 mm to
5 mm, can be a mist
to heavy rains as in a
storm.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Forms of precipitation
• Snow – most common
•
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solid form. Smaller in size
in lower temp because of
lack of moisture.
Sleet – rain freezes in the
air as it falls to the
ground.
If it freezes when it hits
the ground it forms sheet
ice or glaze ice.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Forms of precipitation • Hail – lumps of ice
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that are spherical or
irregular in shape.
Form in normally in
cumulonimbus clouds,
rain gets pushed
through a freeze layer
and wind currents
push it up and down
several times.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Causes of
precipitation
• Water droplets are
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normally small
enough to stay in the
air.
If the size increases
100 times from 20
micrometers, they will
begin to fall
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Coalescence
• Rain drop size is
•
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determined by the
size of the nuclei.
As droplets collide
they get larger until it
comes down as rain.
Coalescences is how
rain forms in the
tropics.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Supercooling
• Water temps may go as
•
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low as -100C.
They do not freeze
unless they have a
freezing nuclei to attach
to.
Once the process starts,
crystals form quickly and
fall as snow or rain
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Cloud seeding
• They add freezing nuclei
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to the cloud like: silver
iodine (from flares or
burners) or powdered
dry ice.
Conflicting evidence on
effect, it may someday
help end droughts and
control storms.
list the conditions that must exist
for a cloud to form
Notes chapter 24 section 3
• Measuring precipitation
• Three types: a wide funnel
attached to a cylindrical
container, one that dumps
when it reaches a certain level,
and the last weighs the amount
of water in the bucket.
• Only measure in one small
area.
• Snow is measured by depth
and water volume, average is
10cm of snow per 1cm of water
list the conditions that must exist
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for a cloud to form