Warm Up 3/4/08Warm Up 3/4/08

1.1. True or False: The seasons are caused by True or False: The seasons are caused by changes in Earth’s distance from the sun.changes in Earth’s distance from the sun.

FalseFalse

2.2. Does land or water heat more rapidly?Does land or water heat more rapidly? Land heats more rapidlyLand heats more rapidly

3.3. If you move from sea level to a location in If you move from sea level to a location in the mountains, how will the temperature the mountains, how will the temperature change?change?

It will get colderIt will get colder

Atmosphere CharacteristicsAtmosphere Characteristics

Chapter 17, Section 1Chapter 17, Section 1

WeatherWeather No other planet in our solar system has an No other planet in our solar system has an

atmosphere with the exact mixture of gases or the atmosphere with the exact mixture of gases or the moisture conditions and heat needed to sustain life as moisture conditions and heat needed to sustain life as we know itwe know it

Weather is constantly changing, and it refers to the Weather is constantly changing, and it refers to the state of the atmosphere at any given time and placestate of the atmosphere at any given time and place

Climate is based on observations of weather that have Climate is based on observations of weather that have been collected over many yearsbeen collected over many years

Climate helps describe a place or regionClimate helps describe a place or region The most important measurable properties of weather The most important measurable properties of weather

and climate are air temperature, humidity, type and and climate are air temperature, humidity, type and amount of precipitation, air pressure, and the speed amount of precipitation, air pressure, and the speed and direction of windand direction of wind

WeatherWeather

Concept CheckConcept Check

How does weather differ from climate?How does weather differ from climate? Weather changes constantly, but climate is Weather changes constantly, but climate is

based on patterns of weather that have based on patterns of weather that have been observed over years. Climate helps been observed over years. Climate helps describe a place or region.describe a place or region.

Composition of the Atmosphere – Composition of the Atmosphere – Major ComponentsMajor Components

The composition of the atmosphere has The composition of the atmosphere has changed dramatically over Earth’s nearly 4.6 changed dramatically over Earth’s nearly 4.6 billion year historybillion year history

The atmosphere is thought to have started The atmosphere is thought to have started from gases that were emitted during from gases that were emitted during volcanic eruptionsvolcanic eruptions

Air is a mixture of different gases and Air is a mixture of different gases and particles, each with its own physical particles, each with its own physical propertiesproperties

Two gases—nitrogen and oxygen—make up Two gases—nitrogen and oxygen—make up 99% of the volume of clean, dry air99% of the volume of clean, dry air

Gases Composing Clean, Dry AirGases Composing Clean, Dry Air

Composition of the Atmosphere – Variable ComponentsComposition of the Atmosphere – Variable Components Important materials that vary in the air from time to Important materials that vary in the air from time to

time and place to place include water vapor, dust time and place to place include water vapor, dust particles, and ozoneparticles, and ozone

Water vapor is the source of all clouds and Water vapor is the source of all clouds and precipitation. precipitation.

Movements of the atmosphere allow a large quantity Movements of the atmosphere allow a large quantity of solid and liquid particles to be suspended within itof solid and liquid particles to be suspended within it

Ozone –Ozone – a form of oxygen which combines three a form of oxygen which combines three oxygen atoms into each molecule (Ooxygen atoms into each molecule (O33))

We breath oxygen which has two atoms per molecule We breath oxygen which has two atoms per molecule (O(O22))

Ozone is concentrated 10 to 50 kilometers above Ozone is concentrated 10 to 50 kilometers above Earth’s surfaceEarth’s surface

If ozone did not filter most UV radiation and all of the If ozone did not filter most UV radiation and all of the sun’s UV rays reached the surface of Earth, our planet sun’s UV rays reached the surface of Earth, our planet would be uninhabitable for many living organismswould be uninhabitable for many living organisms

Composition of the Atmosphere – Composition of the Atmosphere – Human InfluenceHuman Influence

Air pollutants are airborne particles and gases that Air pollutants are airborne particles and gases that occur in concentrations large enough to endanger occur in concentrations large enough to endanger the health of organismsthe health of organisms

Primary pollutants, are emitted from identifiable Primary pollutants, are emitted from identifiable sourcessources

Secondary pollutants are not emitted directly into Secondary pollutants are not emitted directly into the air, they form in the air when reactions take the air, they form in the air when reactions take place among primary pollutants and other place among primary pollutants and other substancessubstances

Reactions triggered by strong sunlight are called Reactions triggered by strong sunlight are called photochemical reactionsphotochemical reactions

Primary PollutantsPrimary PollutantsWhat They Are

Carbon Monoxide

49%

Nitrogen Oxides15%

Volatile Organics

14%

Sulfur Oxides

16%

Particulates

6%

Where They Come From

Misc.9%

Solid Waste

Disposal3%

Industrial Processes

15%

Transportation46%

Stationary Source

Fuel Combusti

on27%

Concept CheckConcept Check

What are secondary pollutants?What are secondary pollutants? Secondary pollutants are pollutants that Secondary pollutants are pollutants that

form when reactions take place among form when reactions take place among primary pollutants and other substances.primary pollutants and other substances.

Height and Structure of the Height and Structure of the AtmosphereAtmosphere

The atmosphere thins as you travel away from The atmosphere thins as you travel away from Earth until there are too few gas molecules to Earth until there are too few gas molecules to detectdetect

Atmospheric Pressure – weight of the air above Atmospheric Pressure – weight of the air above (~1000 millibars at sea level)(~1000 millibars at sea level)

The higher you go in the atmosphere, the less air The higher you go in the atmosphere, the less air pressure there will bepressure there will be

The atmosphere can be divided vertically into four The atmosphere can be divided vertically into four layers based on temperature (troposphere, layers based on temperature (troposphere, stratosphere, mesosphere, and thermosphere)stratosphere, mesosphere, and thermosphere)

Atmospheric Atmospheric Pressure Pressure

Variation with Variation with AltitudeAltitude

Layers of the AtmosphereLayers of the Atmosphere Troposphere –Troposphere – bottom layer of atmosphere, bottom layer of atmosphere,

temperature decreases with an increase in altitude temperature decreases with an increase in altitude (~0-12 kilometers)(~0-12 kilometers)

This layer essentially has all the weather phenomenonThis layer essentially has all the weather phenomenon Stratosphere – Stratosphere – temperatures gradually increase due temperatures gradually increase due

to concentration of ozone (~12-50 km)to concentration of ozone (~12-50 km) Mesosphere – Mesosphere – temperatures again decrease with temperatures again decrease with

altitude, going as low as -90ºC (~50-80 km)altitude, going as low as -90ºC (~50-80 km) Thermosphere – Thermosphere – no well defined boundary, no well defined boundary,

temperatures increase, due to short-wave solar temperatures increase, due to short-wave solar radiation being absorbedradiation being absorbed

Thermal Structure of the AtmosphereThermal Structure of the Atmosphere

Earth-Sun RelationshipsEarth-Sun Relationships Solar energy is not evenly distributed over Solar energy is not evenly distributed over

Earth’s surface, but varies with latitude, time Earth’s surface, but varies with latitude, time of day, and season of the yearof day, and season of the year

It is this unequal distribution of heat which It is this unequal distribution of heat which creates winds and drives the ocean’s creates winds and drives the ocean’s currentscurrents

Seasonal changes occur because Earth’s Seasonal changes occur because Earth’s axial position relative to the sun continually axial position relative to the sun continually changes as it travels along its orbitchanges as it travels along its orbit

If the axis were not tilted, we would not have If the axis were not tilted, we would not have seasonal changesseasonal changes

Summer and Winter Solstice occur when Summer and Winter Solstice occur when Earth’s tilt is pointed away from the sunEarth’s tilt is pointed away from the sun

The Autumnal and Spring Equinoxes occur The Autumnal and Spring Equinoxes occur when the sun’s vertical rays strike the when the sun’s vertical rays strike the equator (Earth not tilted towards or away equator (Earth not tilted towards or away from the sun)from the sun)

The length of daylight compared to darkness The length of daylight compared to darkness also is determined by Earth’s position in also is determined by Earth’s position in orbitorbit

Sun Rays Striking EarthSun Rays Striking Earth

Earth-Sun RelationshipsEarth-Sun Relationships

Solstices and EquinoxesSolstices and Equinoxes

Concept CheckConcept Check

In which direction does Earth’s axis point?In which direction does Earth’s axis point? Earth’s axis points toward the North Star.Earth’s axis points toward the North Star.

AssignmentAssignment

Read Chapter 17 (pg. 476-493)Read Chapter 17 (pg. 476-493) Do Chapter 17 Assessment #1-30 (pg. 499-Do Chapter 17 Assessment #1-30 (pg. 499-

500)500) Print out “Investigation 17A – Determining Print out “Investigation 17A – Determining

How Temperature Changes with Altitude”How Temperature Changes with Altitude”

Cool DownCool Down1.1. Why do seasonal changes occur?Why do seasonal changes occur? Seasonal changes occur because Earth’s axis is Seasonal changes occur because Earth’s axis is

tilted. Earth’s orientation to the sun continuously tilted. Earth’s orientation to the sun continuously changes as it travels along its orbit.changes as it travels along its orbit.

2.2. Explain what would happen to air temperatures Explain what would happen to air temperatures in the troposphere if carbon dioxide were in the troposphere if carbon dioxide were removed from air.removed from air.

Because carbon dioxide absorbs heat from Earth Because carbon dioxide absorbs heat from Earth efficiently, air temperatures would decrease if it efficiently, air temperatures would decrease if it were removed from the troposphere.were removed from the troposphere.

3.3. What is one new thing you learned today? What is one new thing you learned today? Explain.Explain.