The AtmosphereThe Atmosphere

Chapter 6 Notes

Composition of the AtmosphereComposition of the Atmosphere

• Atmosphere: a mixture of gasses that surround the Earth

• Contains the oxygen you breathe and protects you from harmful rays from the sun.

• Water Vapor: make up part of the atmosphere . When conditions change the water vapor can change to a liquid (rain) or solid (snow)

Atmospheric Pressure Atmospheric Pressure

• The atmosphere is held around Earth by gravity.

• Gravity pulls gas molecules toward Earth’s surface which causes Air Pressure.

• Air Pressure: the measure of the force with which air molecules push on a surface

Air PressureAir Pressure

• Air pressure is strongest on Earth’s surface.

• As altitude increases the pressure decreases.

Atmospheric TemperatureAtmospheric Temperature

• Differences in the temperature of the atmosphere result from the amount of solar energy absorbed.

• Some parts contain more gases which make them absorb more solar energy

• Other parts contain less gases which mean they are absorb less solar energy and are cooler.

Layers of the AtmosphereLayers of the Atmosphere

Draw this picture

The First LayerThe First Layer

• Troposphere– Lowest layer next to Earth’s surface– Densest layer– Contains 90% of the mass of the atmosphere– The layer we live in– Gases continuously mix in this layer – Temperatures vary in this layer

The Second LayerThe Second Layer

• Stratosphere– Gases are layered and do not mix in this layer– The air is very thin and contains little moisture– Lower stratosphere is very cold -60 degree

temp. But temperatures rise as altitudes rise – This layer is the home of the ozone layer, a

protective layer that soaks of ultraviolet rays from the sun.

troposphere

stratosphere

The Third LayerThe Third Layer

• Mesosphere– The coldest layer– Temperatures can be as low as -93 degrees

Celsius at the top of the Mesosphere

The Fourth LayerThe Fourth Layer

• Thermosphere– High temperatures 1000 degrees Celsius or

higher– It does not feel hot. The particles are moving

very fast but they are not heating up.

IonosphereIonosphere

• This occurs between the mesosphere and thermosphere.

• Gas particles become electrically charged particles called ions

• These ions radiate energy in the form of shimmering light called auroras

Atmospheric HeatingAtmospheric Heating

• Energy from the sun is absorbed by the atmosphere, land, and water and is changed into thermal energy.

Heat TransferConduction, Convection and

Radiation

Heat TransferConduction, Convection and

Radiation

To Make Foldable:To Make Foldable:1. On the short side of the paper, fold it down an inch.2. Now fold it in half, hamburger style.3. Now fold it in 1/3.

Conduction

Convection

Radiation

Heat T

ransfer

Examples Definition

Examples Definition

Examples Definition

Outside of Foldable Inside of Foldable

Thermal Energy TransferThermal Energy Transfer• Thermal energy transfer is heat moving

from a warmer object to a cooler object. This is known as thermal energy transfer.

How is Heat Transferred?How is Heat Transferred?There are THREE ways heat can move.

– Conduction

– Convection

– Radiation

CONDUCTIONCONDUCTION

• Heat is transferred from one particle of matter to another in an object.

• Conduction = CONTACT/ TOUCH

Have you ever…Have you ever…

• Touched a metal spoon sitting in a pan of boiling water only to be surprised by HOW hot it is??

Think back to what you know about metals and nonmetals. What conducts heat better, metal or nonmetal? Why?

Example of ConductionExample of Conduction

• Think of a metal spoon in a pot of water being heated.

• The fast-moving particles of the fire collide with the slow-moving particles of the cool pot.

• Because of these collisions, the slower particles move faster and heat is transferred.

• Then the particles of the pot collide with the particles in the water, which collide with the particles at one end of the spoon.

• As the particles move faster, the metal spoon gets hotter. This process of conduction is repeated all along the metal until the entire spoon is hot.

EXAMPLE OF CONDUCTIONEXAMPLE OF CONDUCTION

• A piece of cheese melts as heat is transferred from the meat to the cheese (Contact)

CONVECTIONCONVECTION• Convection is the movement that transfers heat within

fluids and air (gas)• Heat is transferred by currents within the fluid or gas

• Convection = VENTS (through air and liquid particles)

• Convection moves in a circular pattern

Examples of Convection:Examples of Convection:• Have you ever noticed that the air near the ceiling is

warmer than the air near the floor? Or that water in a pool is cooler at the deep end?

• Examples: air movement in a home, pot of heating water.

• Pick one of these examples and draw the circular pattern in your notes.

Explaining ConvectionExplaining Convection• Convection

currents cause the cooler breezes you experience by a large body of water.

• These currents also cause the movement of magma within the earth.

RADIATIONRADIATION• Radiation is the transfer of energy by

electromagnetic waves• Radiation does NOT require matter to

transfer thermal energy• Radiation = Radiates (heat escaping the sun)

Radiation May Come From Other Sources

Radiation May Come From Other Sources

Have you ever sat too close to a campfire while cooking marshmallows? You’re enjoying the warmth ….. only to notice that your skin is really warm?

Examples of RADIATIONExamples of RADIATION

1. Fire

2. Heat Lamps

3. Sun

Radiation: Energy Transfer by Waves

Radiation: Energy Transfer by Waves

• Radiation is the transfer of energy as electromagnetic waves.

• The sun radiates huge amounts of energy But Earth only receives two-billionths of this energy

• Energy from the sun drives the weather and makes Earth habitable.

Conduction: Energy Transfer by Contact

Conduction: Energy Transfer by Contact

• Thermal Conduction is the transfer of energy through a material

• Always transferred from warm to cold areas

• Occurs when air molecules come in direct contact with the warm surface of the Earth.

Convection: Energy Transfer by Circulation

Convection: Energy Transfer by Circulation

• Convection is the transfer of thermal energy by the circulation or movement of a liquid or gas

• Most thermal energy is transferred through convection

Convection Convection • Example, as air is

heated, it becomes less dense and rises. Cool air is denser, so it sinks. As the cool air sinks, it pushes the warm air up. The cool air is eventually heated by the Earth's surface and begins to rise again. This is called a convection current

Greenhouse EffectGreenhouse Effect

• 70% of the radiation that enters the atmosphere is absorbed by the clouds or by the Earth’s surface.

• The energy is converted into thermal energy.

Greenhouse EffectGreenhouse Effect

• The greenhouse effect is the process by which the gases in the atmosphere absorb thermal energy and radiate it back to the Earth.

• Acts much like the glass walls and roof in a greenhouse.

Radiation BalanceRadiation Balance

• In order for the Earth to remain livable, the amount of radiation coming into the Earth must equal the amount of thermal energy the Earth releases into space.

• There must be BALANCE!!

Global WarmingGlobal Warming

• Global warming is the gradual increase in average global temperature

• Causes the icecaps to start to melt

• Possible causes– Too many greenhouse gases– Human activity

• People are not doing their part to keep the Earth clean and safe

• Using too many Fossil Fuels!!

Global Winds and Local WindsGlobal Winds and Local Winds

• Wind: the movement of air caused by differences in air pressure

• The greater the pressure, the faster the wind moves.

• Ex: Hurricanes

Hurricane AndrewHurricane Andrew

Air Rises at the Equator and Sinks at the Poles

Air Rises at the Equator and Sinks at the Poles

• Differences in air pressure are caused by unequal heating of the Earth.

Equator Poles

•Receives more solar energy•Air is warmer and less dense•The air rises creating an area of low pressure•The warm air flows towards the poles

•Receives the warm air, which becomes colder and denser•The cold air sinks creating an area of high pressure•The cold air then flows back towards the equator.

Pressure belts are found every 30ºPressure belts are found every 30º

• Air travels in many large circular patterns called convection cells.

• Convection cells are separated by pressure belts that include bands of high and low pressure every 30° of latitude

Coriolis EffectCoriolis Effect• The Coriolis effect is

the apparent curving motion of winds and ocean currents due to Earth’s rotation.

• Northern Hemisphere the winds traveling north curve to the east and winds traveling to the south curve to the west

Global WindsGlobal Winds

• The combination of convection cells found at every 30º of latitude and the Coriolis effect produces patterns of air circulation called global winds.

Polar EasterliesPolar Easterlies

• The wind belts that extend from the poles to 60° latitude in both hemispheres are called the polar easterlies.

• They are formed as the cold sinking air moves from the poles toward 60° north and 60° south latitude.

• The polar easterlies are responsible for bringing cold arctic air over the United States.

Prevailing WesterliesPrevailing Westerlies

• The wind belts found between 30° and 60° latitude in both hemispheres are called the westerlies.

• The westerlies flow towards the poles from west to east

• The westerlies are responsible for bringing moist air to the United States.

Trade WindsTrade Winds

• The winds that blow from 30° latitude almost to the equator are called trade winds.

• The Coriolis effect causes the trade winds to curve west in the Northern Hemisphere and east in the Southern Hemisphere

• Early traders used these winds to sail from Europe to the Americas.

The DoldrumsThe Doldrums

• The trade winds meet in an area around the equator called the doldrums.

• There is very little wind because there is very low pressure.

• This is why it is called the doldrums.

Horse LatitudesHorse Latitudes

• At about 30° north and 30° south latitude, sinking air creates an area of high pressure. The winds are weak in this area called the horse latitudes.

• Legend says that sailors would get stuck in this windless area. Instead of wasting drinking water they would through the horses overboard.

• Most of the Earth’s deserts are located at this latitude.

Jet Streams: Atmospheric Conveyor Belts

Jet Streams: Atmospheric Conveyor Belts

• Jet Streams are a narrow belt of strong winds that blow in the upper troposphere.

• Can reach maximum speeds of 400km/h

• Do not follow regular patterns

• Important for pilots and meteorologists.

Local WindsLocal Winds

• Local winds move short distances and can blow from any direction.

• Shorelines or mountains can create local wind patterns

• Sea Breeze- during the day, air over the ocean is cooler and forms an area of high pressure. The cool air flows to the land producing a sea breeze.

• Land Breeze- at night air over the land is cooler and forms an area of high pressure. The cooler air moves toward the ocean producing a land breeze.

Sea and Land BreezesSea and Land Breezes

•Mountain Breeze- at night air along the mountain slopes cool . This cool air moves down the slopes into the valley producing a mountain breeze.

• Valley Breeze – during the day, the sun warms the air along the mountain slopes. This warm air rises up the mountain creating a valley breeze.

Air PollutionAir Pollution

• In December 1952, one of London's dreaded "pea souper" fogs settled on the city. But this was no ordinary fog—it was thick with coal smoke and air pollution. It burned people's lungs, and the sky grew so dark that people could not see their hands in front of their faces. When the fog lifted four days later, thousands of people were dead!

Air PollutionAir Pollution

• Air Pollution is the contamination of the atmosphere by the introduction of pollution from human and natural sources

• Air pollution is common in many places

• Must be reduced

Primary PollutantsPrimary Pollutants

• Pollutants that are put directly into the air by humans or natural activity are primary pollutants

• Ex: dust, sea salt, volcanic gases and ash, smoke for forest fires, and pollen, carbon monoxide, dust, smoke, vehicle exhaust

Primary PollutantsPrimary Pollutants

Secondary PollutantsSecondary Pollutants

• Pollutants that form when primary pollutants react with other primary pollutants or with naturally occurring substances are secondary pollutants.

• Ex: ozone and smog

Formation of SmogFormation of Smog

• Smog forms when ozone and vehicle exhaust react with sunlight

• Pollution controls have been put in effect in some places to control the amount of pollution and reduce the amount of smog.

Sources of human caused air pollution

Sources of human caused air pollution

• Transportation is a major cause of air pollution

• It causes10-20 % of the pollution in the United States

• Vehicle exhaust contains nitrogen oxide which contributes to smog

Industrial Air PollutionIndustrial Air Pollution

• Industrial plants and electrical power plants burn fossil fuels to produce energy.

• Oil refineries, chemical manufacturing plants, dry-cleaning businesses, furniture refinishers, and auto body shops all produce air pollution.

Indoor Air PollutionIndoor Air Pollution

Indoor Air Pollution Indoor Air Pollution

• Indoor air pollution can be reduced by– Ventilation-mixing of indoor air with outdoor

air– Reduce indoor air pollution by limiting the use

of chemical solvents and cleaners

Acid PrecipitationAcid Precipitation

• Precipitation such as rain, sleet, or snow that contains acids from air pollution is called acid precipitation.

• The burning of fossil fuels releases sulfur dioxide and nitrogen oxide into the atmosphere.

• They combine with water in the atmosphere to form sulfuric acid and nitric acid.

Acid Precipitation and PlantsAcid Precipitation and Plants

• Soil naturally has acid.

• Acid precipitation can cause the soil acidity to increase

• This is called acidification.

• When acidification occurs – Some nutrients are dissolved– Aluminum and toxic metals are released and

absorbed by the roots of plants

The Effects of Acid Precipitation on Forests

The Effects of Acid Precipitation on Forests

• Eastern Europe :Poland

• Forests have been severely damaged by acid precipitation

Acid Precipitation and Aquatic Ecosystems

Acid Precipitation and Aquatic Ecosystems

• If the amount of acid increases in the water then the plants, fish, and other organisms may die.

• A rapid change in a body of water’s acidity is called acid shock.

• Some communities use powered lime a base to reduce the amount of acid in the water.

The Ozone HoleThe Ozone Hole

• 1985 scientists reported that the ozone layer over Antarctic regions was thinning.

• Chemicals called CFC were causing the ozone to break down into oxygen

The Ozone HoleThe Ozone Hole

•1987 action was taken to solve the ozone problem•A ban of all CFC chemicals was created•CFC alternatives were developed•CFC chemicals take 60 to 120 years to quit working. Therefore even with the ban CFC’s used 30 years ago are still harming the ozone now!!!

Air Pollution and Human Health Air Pollution and Human Health

Short Term Effects Long Term Effects

•Headache•Nausea•Irritation to eyes, nose, and throat•Coughing•Upper respiratory infection•Worsening of asthma and emphysema

•Emphysema•Lung cancer•Permanent lung damage•Heart disease

Cleaning up air pollutionCleaning up air pollution

• 1970 the United States Clean Air Act was passed by Congress.

• This act gives the Environmental Protection Agency the authority to control the amount of pollutants that can be released from any source.

• The EPA checks air quality.

• The Clean Air Act was strengthened in 1990.

Air Pollution from IndustryAir Pollution from Industry

• The Clean Air Act requires factories to use scrubbers.

• A scrubber is a device that is used to remove some pollutants before they are released by smokestacks.

The Allowance Trading SystemThe Allowance Trading System

• The Allowance Trading System – the EPA gives allowances for the amount of pollutants that companies can release.

• If a company goes over--- they pay fines.

• If a company is under they can sell there extra allowances to other businesses.

Reducing Air Pollution from Vehicles

Reducing Air Pollution from Vehicles

• The EPA requires car makers to meet certain criteria for exhaust.

• Use of cleaner fuels and more efficient engines

• Hybrids, carpools, public transportation, or biking and walking all reduce air pollution.