Download Unit 6: Weather Climate

Unit 8: Weather and Climate- Part I
I The Earths Atmosphere is the thin layer
of gases surrounding the hydrosphere
(water) and lithosphere (crust).
A. Origin of the Atmosphere
See ESRT p.8
1. Most likely first formed from gases
released by volcanoes (outgassing).
 First composed of Nitrogen (N2), Water
vapor (H2O), and Carbon Dioxide (CO2)
and …
no Oxygen (O2)
2. one-celled living things used CO2 for
photosynthesis and released O2 as a
waste product.
3. From ____ MYA to ____ MYA O2
combined with dissolved iron in the
ocean to form iron oxide.
The “rusting of the oceans’.
This formed thick Banded Iron
Formations all around the world.
banded iron formation - Google Search
When all the iron in the ocean was
rusted…
4. O2 slowly built up in the atmosphere
starting at about _____ MYA
(see ESRT p.9)
B. The Composition of Atmosphere today
is about
 78% N2,
 21% O2,
 1% other gases-
mainly Argon, Water Vapor (H2O), and
Carbon Dioxide (CO2 )
(See ESRT p.1)
YouTube - Evolution of the atmosphere
C. Layers of the Atmosphere
(see ESRT p.14)
What holds an airplane up?
How high can an airplane fly?
Can it fly into space?
YouTube - Chuck Yeager Pushing The Limits (The Right Stuff)
1. Troposphere:
 From surface to about km. or mi. in
altitude.
 Air temp. ____________ with increasing
altitude.
 Contains all the water vapor, clouds, and
weather. (ESRT p.14)
 Upper boundary called the Tropopause.
2. Stratosphere:
 Rises to about _____ km. or _____ mi.
YouTube - Flying to the Stratosphere (start 3:15)
 Temperature __________ with
increasing altitude.
 Upper boundary called the Stratopause.
 Contains the Ozone Layer of gases.
 Ozone (O3) absorbs dangerous
ultraviolet sunlight and protects living
things.
Human activities have decreased the
amount of ozone.
This could endanger living things.
YouTube - Ozone layer (104)
3. Mesosphere:
 Rises to about _____ km. or _____ mi.
 Temperature ___________ with
increasing altitude.
 Meteors burn up in this layer due to
friction with air.

This forms “shooting stars”.
YouTube - Perseid meteor shower
4. Thermosphere:
 Gradually blends into the vacuum of
space.
 Temp. __________ with increasing
altitude.
 Contains Aurora’s or the Northern and
Southern Lights. (see text p.688)
http://svs.gsfc.nasa.gov/vis/a010000/a010000/a010014/a010014_H264_640x480.mp4
[Lab: Temp. of the Atmosphere]
II Heat and the Atmophere
A. Air Temperature is measured using 3
scales: °F, °C, and °K
(See ESRT p.13)
Practice:
1. Each mark on the °F scale = _____
2. Each mark on the °C scale = _____
3. Each mark on the °K scale = _____
4. 60° F. = _____ °C. = _____ °K.
5. 10° C. = _____ °F. = _____°K.
6. 277° K. = _____ °C. = _____ °F.
7. 108° F. = _____ °C. = _____ °K.
B.How the atmosphere is heated:
1. Conduction: transfer of heat energy by
direct collision of atoms. This usually
occurs in Solids. (see text p.483)
Ex. Air is heated by touching the warm
ground.
[Diagram]
2. Convection: transfer of heat energy in
liquids and gases (or fluids) caused by
density differences.
[Diagram]
Convection occurs in the atmosphere,
oceans and mantle of the Earth
3. Radiation: is the transfer of heat by
Electromagnetic (EM) waves.
 EM radiation travels at the “speed of
light” (about 186,000 miles / second).
 Can travel through gases, liquids, and
some solids.
 Can travel through the vacuum of
space.
C. Sunlight is composed of many types of
EM Energy (see text p.484 and ESRT p.14)
[diagram]
Electromagnetic spectrum | Flash simulation, Animation, Illustration,
Picture, Diagram – eduMedia
2. The greatest intensity of sunlight, at the
Earths surface is in the visible wavelengths.
(Text p.675)
[diagram]
B. Factors Affecting Daily Temp.
Changes
1.Time of Day:
Warmest time of day is…
the mid-afternoon (around 3:00 PM)
This is when Ground Radiation is greatest.
Greenhouse Effect – animated diagram
[Diagram]
Coldest time of day is …
around sunrise (6: 00 AM)
This is when Ground Radiation is lowest.
[Graph]
2. Cloud Cover
 Clouds block incoming sunlight.
 This makes day time temp. cooler.
 Clouds trap outgoing ground
radiation.
 This makes night time temp. warmer.
 Clouds decrease the
Daily Temperature Range.
3.The movement of Cold and Warm
Air Masses has the greatest affect on day
to day temp. changes.
(see text p.559-560)
II Air Pressure is the weight of the
atmosphere pressing down on the surface.
How come we don’t feel it?
Swimming pool/equalize air pressure
Train to Penn Station
Driving on hilly road
Airplane ascent/descent.
A. Air Pressure is measured using a
Barometer (see text p.533).
Average air pressure is about:
29.92 inches of Mercury or
1013.2 millibars (mb.) or
1.0 atmospheres (atm.)
Vidclip- Atmospheres_of_Pressure
B. Conversions- Practice (see ESRT p.13)
1. Each mark on the millibar scale = _____
mb.
2. Each mark on the inches scale = _____
inches
3.1020 mb. = _____ inches.
4.1021 mb. = _____ inches.
5.29.00 inches = _____ mb.
6.28.88 inches = _____ mb.
C. Factors affecting the Air Pressure
1. Elevation: the greater the altitude the less
the air pressure.
(see ESRT p.14)
Practice:
Pressure at Sea level = _____ atm.
Pressure at Tropopause = _____ atm.
Pressure at altitude of 15 miles = _____ atm.
Pressure at altitude of 40 km. = _____ atm.
Lower air pressure affects many things:
More difficult to breathe at high altitude.
Vidclip – Air_Density and_the_Effects_on_the_Human_Body
Air less dense, easier to hit a home run.
http://profhorn.meteor.wisc.edu/wxwise/baseball/homerun.html
2. Temperature: Warm air is lighter and
lower pressure than cold air.
[Why?- diagram]
3. Humidity: Moist, humid air is lighter and
lower pressure than dry air.
[Why?]
Lowest Pressure air is Warm and Moist.
Highest Pressure air is Cold and Dry.
YouTube – Air Pressure – Science Theater 4
Try to sink a basket! Change the air pressure in the ball.
YouTube – Bill Nye the Science Guy – “Smells Like Air Pressure”
III Wind is the movement of air from
areas of High Pressure to Low Pressure.
[Diagram]
A. Wind velocity is measured with an
 Anemometer for speed and a
 Wind Vane for direction.
(see text p. 545)
 Wind Direction is always labeled from
where it comes from (not going to).
B. Local Winds blow over a small distance
and often change direction.
Examples:
 Valley and Mountain Breezes
(text p.544)
 Land and Sea Breezes (text p.543-544)
Observe an animation of land and sea breezes.
YouTube – WeatherBug’s Real World Instruction: Wind
[Diagram]
C. Global Winds blow long distances from
the same general direction.
[Set up Diagram]
 In the tropics:
-Heating of the sun warms and moistens air.
-Density decreases and air rises.
-This forms a permanent low pressure
zone along the equator.
 Along latitudes 30° N. and 30° S.
-Air cools and dries.
-Density increases and air sinks
-This forms permanent high pressure
zones
 Wind then blows from 30° (high
pressure) to the equator (low pressure).
 These winds are called the
Trade Winds.
 Circular movement of air is called a
Convection Cell.
global wind animation
D. Global Wind direction curves due to the
rotation of the Earth. This is called the
Coriollis Effect.
[Diagram 2]
(See ESRT p.14)
YouTube – Reference Table p 14 Global Winds.mov
Sailing around the world using Global Winds 1
Sailing around the world using global winds 2
YouTube – global wind visualisation
E. Winds often circulate around centers of
High and Low Pressure.
B. In a Low Pressure System or Cyclone,
wind circulates counterclockwise and
inward towards the center.
Air rises upward in the center.
[Diagram]
B. In a High Pressure System or
Anticyclone, wind circulates clockwise
and outward from the center.
wind circulation NH
[Diagram]
Centers of High and Low Pressure in the
U.S. right now:
National and Local Weather Forecast, Hurricane, Radar and Report
In the Southern Hemisphere, winds
circulate the opposite way.
BOM_Air pressure
F. Isobars are isolines of equal air pressure.
[Diagram]
The closer the isobars,
 the faster the pressure is changing,
 the greater the pressure gradient
 the greater the wind speed.
[Reverse statement?]
G. Pressure Gradient can also be
calculated.
Use the formula in ESRT- p.1
[Example: Board]
YouTube – Wind.mov
Lab: Wind Patterns
IV Water and the Atmosphere
A. Water exists in three states or phases.
[Diagram- phase changes]
(see text p.505)
B. Water heats up and cools down slowly
because it has a high Specific Heat.
(see ESRT p.1)
C. The Heating Curve for Water
[Diagram- Graph]
Heating curve for water
Heating curve for water
A – B: Ice absorbs heat. Temp. increases.
B – C: Ice absorbs heat and melts. No
Change in temp.
C – D: Liquid water absorbs heat.
Temp. increases.
D – E: Liquid water absorbs heat and
boils (vaporizes).
No change in temp.
E – F: Water vapor absorbs heat.
Temp. increases.
1. Facts to Know: see ESRT p.1
 Vaporization absorbs heat (2,260
Joules / gram). This cools the
environment.
(sweating, dogs panting, wet skin-cold)
 Condensation releases this heat and
warms the environment.
(source of heat for hurricanes)
 Melting absorbs heat and cools the
the environment (334 joules, gram).
(ice cubes in drink)
 Freezing releases this heat and warms
the environment.
D. Water in the air.
1. Humidity is the amount of water vapor
the air contains.
2. Warm air can hold more vapor than
cold air. (see text p.506)
Warm air has a greater vapor capacity.
[Diagram]
E. Relative Humidity (RH) is the actual
amount of vapor in the air compared to
its vapor capacity.
“How full the air is with water vapor.”
YouTube - relative humidity
8(c) Atmospheric Humidity diagram
[diagram]
F. RH increases if;
a. More vapor enters the air by
evaporation or transpiration.
b.The temp. decreases.
[demo]
YouTube - Relative Humidity Demo
YouTube - Jeanetta Jones explains about relative humidity
Relative Humidity in your house in Winter- have fun!
G. When RH = 100%, the air is saturated,
and condensation may occur.
H. Dew Point is the temp. at which the air
becomes saturated with vapor.
The closer the air temp to the Dew Point
temp., the higher the RH, and the greater the
chance of clouds and condensation.
[Graph]
I. The instrument used to measure Dew
Point temp. and RH is the
Sling Psychrometer.
1. It has two thermometers; a Wet Bulb
and a Dry Bulb.
2. Water evaporates from the wet bulb and
cools it.
3. The wet bulb temp. is always less than
or equal to the dry bulb temp.
4. Use the ESRT (p.12) to determine Dew
Point temp and RH.
[Examples: on board]
V Clouds and Precipitation
A. Clouds form when air rises, expands,
and cools.
(See text p.503, 510, 511)
YouTube - Timelapse of Tucson cloud formations
YouTube - White Clouds Time Lapse
YouTube - Clouds
1. When the air is cooled to the dew point
temp., condensation occurs forming
clouds.
2. What makes air rise?
http://earthsci.org/processes/weather/weaimages/cldform.gif
 Heating by the sun.
[Diagram]
 Different types of air collide.
[Diagram]
 Air rises up and over mountains.
[Diagram]
3. Conditions necessary for condensation
and cloud formation:
 Air Temp. = Dew Point temp.
 Small solid particles called
Condensation Nuclei, are present.
(Examples: dust, pollen, sea salt)
 If air is too clean and no nuclei are
present, the air may become
Supersaturated.
Cloud Seeding can make condensation
occur.
YouTube - How Does Cloud Seeding Work?
YouTube - Cloud seeding vid
YouTube - Chinese fight drought with chemical cloud-seeding
B. Types of Clouds:
See text p.518-519, Cumulus text p.515
p.517- cirrus
C. Precipitation occurs when water droplets
or ice crystals grow heavy enough to fall
to the Earths surface.
http://earthsci.org/processes/weather/weaimages/ccprcess.gif
1. The type of precipitation that falls
depends on the temp. of the air at
different levels.
Precipitation Type
2. Types of Precipitation
 Rain: all liquid water.
 Snow: Vapor changes directly into ice
crystals.
snowflakes - Google Image Search
 Sleet: raindrops freeze while falling to
the ground.
 Hail: Ice pellets collide with raindrops
and freeze.
Examine an animation of hail forming.
hail - Google Image Search
 Glaze (ice storms): Liquid water
freezes on contact with frozen ground.
ice storm - Google Image Search
http://profhorn.meteor.wisc.edu/wxwise/baseball/homerun.html
Hurricane animations
Hurricane Visualizations
Photo of Earths atmosphere
The Earth's Atmosphere