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Mixture of Gases in Air

All Other Gases

Argon = 0.93%

Carbon Dioxide = 0.04%

Largest Jar = ____ sec Medium Jar = ____ sec Small Jar = ____ sec

21% Oxygen in all Jars – but that equals a

smaller amount of oxygen in a small jar

How long will the candle burn?

Largest Jar = ____ sec Medium Jar = ____ sec Small Jar = ____ sec

1)

2)

Mixture of Gases in Air

All Other Gases

Argon = 0.93%

Carbon Dioxide = 0.04%

NITROGEN

• A major part of proteins, including

DNA

• Dilutes (thins out) the oxygen – too

much or too little oxygen and we

would die!

• Turned into useful form

by nitrogen-fixing bacteria

OXYGEN• Necessary to survive!

• Our cells use oxygen to

create energy

• All of the oxygen in our

atmosphere has been

created by plants –

photosynthesis!

• Burning requires oxygen

CARBON DIOXIDE

• Used by plants for photosynthesis

• A greenhouse gas – carbon dioxide

helps keep our planet warm

• Increases in CO2 have been making

the planet warmer: global warming!

TRACE GASES

• OZONE helps filter out the

sun’s harmful rays

• ARGON is used in light bulbs

because it will not catch fire

even in extreme heat

• WATER VAPOR can condense

to form clouds

• HELIUM inflates balloons and

blimps

WRITING IN SCIENCE

• Write a paragraph that

summarizes in your own

words how oxygen from the

atmosphere is important.

Include its importance to

living things and in other

processes.

Why is the atmosphere important?

• Has oxygen that living things

need to survive.

• Traps energy from the sun

keeping earth warm

• Protects living things from

dangerous radiation from the

sun.

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Exploring Air with SyringesToday, you will investigate air with syringes and

tubing – work on your own or with your group.

In your science notebook, copy and

answer the following questions:

1) What happens to the air in the syringe

when you push/pull on the plunger?

2) What can air do?

3) Record 3 observations & 1 question.

*SAFETY – Be careful with the materials! Do not

point either end of the syringe at another student.

Exploring Air with SyringesBased on the investigation:

What can air do?

A few words you need to know…

Compress – means to squeeze into a smaller

space

Density – the amount of mass (stuff) in a

certain amount of space (volume)

Air Pressure – the force of air pushing on stuff

Barometer – a tool that measures air pressure

Air Pressure in a SyringeWhich syringe has the air under greater pressure?

High

Pressure

Low

Pressure

Air Pressure in a BalloonIs the density of air molecules in a balloon

greater than or less than the surrounding air?

Higher

Pressure

& Density

Lower

Pressure

& Density

Air Pressure at Different AltitudesIs air pressure greater at sea level or on top

of a mountain?

More

Pressure

& Density

Less

Pressure

& Density

Sea Level (Low altitude)

Mountains

(High altitude)

TROPOSPHERE• Thinnest Layer (0-12 km)

• Average Temperature of 25°C

(Temperature drops as you go higher)

• All of Earth’s weather happens here.

• Air here contains water & dust.

• Most of the atmosphere’s air is here (this

layer is very dense).

STRATOSPHERE• 10-50 km above earth’s surface

• There is almost no water or dust in this

layer.

• Contains the OZONE LAYER (which

absorbs UV radiation from the sun)

• Very cold, until the top of the layer,

where it warms to 0°C.

MESOSPHERE• 50-80 km above Earth’s surface.

• Temperature plunges to -90°C (the

coldest in the atmosphere)

• Meteors burn up here while entering the

atmosphere.

THERMOSPHERE• Thickest layer (80-400 km above Earth’s

surface).

• Air is extremely thin. Atmospheric gases

fade into outer space.

• Temperature can spike to 1,800°C.

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What is

HEAT?What is “temperature?”

Where does our heat energy

come from?

Why do some things heat up

more than others on a hot day?

What do

“hot” and

“cold” really

mean?

What is heat, anyway?

• Temperature is a measure of the

average amount of energy of motion

for each particle of a substance

Cold

Water

Slow-

Moving

Molecules

What is heat, anyway?

• Temperature is a measure of the

average amount of energy of motion

for each particle of a substance

• Let’s act it out!

Hot

Water

Fast-

Moving

Molecules

Where does the energy come

from?

• Nearly all the energy that heats our

atmosphere comes from the sun.

• Not all sunlight reaches the ground.

Some sunlight is absorbed or

reflected before it reaches the

surface.

Where does the energy go? Where does the energy go?

Where does the energy go?

• Not all surfaces absorb the sun’s

energy equally.

• The color and material of the surface

will determine how much of the

energy is absorbed and how much is

reflected.

Water

Rocks

Grass

Sand

How does heat move?

• HEAT is the transfer of thermal

energy from a hotter object to a

cooler one.

• Thermal

energy is moving

from the air,

which is

warmer, to the

snowman, which

is cooler.

How does heat move?

• Heat can be transferred in three

ways: radiation, conduction, and

convection.

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RADIATION

• Radiation is the direct transfer of

energy by electromagnetic waves.

• Radiation does not need any material

to travel through!

• Energy from the sun gets to us

through radiation.

CONDUCTION• Conduction is the direct transfer of heat

from one material to another that is

touching it.

• When a faster-moving molecule bumps into

a slower-moving molecule, the slower one

speeds up.

• Conduction works best in solids.

Metal is a

good

conductor –

the heat

moves to the

girl’s hand.

Wood is

not a good

conductor.

CONVECTION

• Convection is the transfer of heat by the

movement of particles in a fluid (liquid or

gas).

• As fluids heat up or cool down, their

density changes. Lower-density materials

will rise above higher-density materials.

HEAT TRANSFERRadiation, Conduction, or

Convection?

• You feel the warmth of the

sun’s rays on your face

outside.

• You notice your macaroni

moving up and down in the

boiling water.

• At the beach, you step on the

hot sand and it burns your

feet.

RADIATION

CONVECTION

CONDUCTION

Water in the Atmosphere

Earth is called the “Water Planet”

• 71% of the earth’s surface is covered

by water.

• Water is essential for LIFE on earth.

Water on earth’s surface is easy to see…

• Oceans

• Lakes

• Rivers

• Glaciers

But what about water in earth’s atmosphere???

Water in the atmosphereIt’s less obvious than surface water, but there are many signs of water in the atmosphere:

•Rain, Snow, Drizzle

•Clouds & Fog

•Hot days that feel “muggy” or “humid”

•Dew on the grassin the morning

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Water Cycle

• The movement of water between the atmosphere

and earth’s surface is the water cycle.

How does water get into the air?

• EVAPORATION – is the process where liquid water molecules escape into the airas water vapor.

• 3 things affect how quickly water evaporates:

1) Temperature

2) Wind

3) Humidity of the air

How much water can air hold?

• HUMIDITY is the measure of how much

water vapor is in the air.

• TEMPERATURE affects how much

water vapor the air can hold…

holds MORE water vapor. holds LESS water vapor.

That’s why air feels more “HUMID” on hot days!

What is the “Dew Point”?

• As air cools, the amount of water vapor it can hold decreases.

• At a certain temperature, the water vapor in the air will CONDENSE back into water droplets or ice.

• This temperature is the “DEW POINT”.

What is the “Dew Point”?

• So, when the air temperature equals the “Dew Point” temperature, the air cannot hold any more water.

That means relative humidity is 100%!

Ever wondered about why the grass (or a car windshield) is wet in the morning?

Overnight, the temperature droppedbelow the “dew point” temperature, and the water in the air condensed into water droplets on the grass.

CLOUDS

What are CLOUDS?• They are made of tiny water droplets or

ice crystals.

• They form when water condenses onto small particles in the air (like dust).

How TINY are the water droplets?

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How do clouds form?2) Air cools to dew point causing condensation.3) Water vapor condenses forming a cloud.1) Warm, moist air rises and cools. Clouds are NOT all the same…Flat clouds =

“Stratus”

Fluffy clouds =“Cumulus”

Wispy clouds =“Cirrus”

Clouds are classified according to SHAPE

Clouds are also classified by ALTITUDE

HIGH LEVEL (cirro-)

MID LEVEL (alto-)

LOW LEVEL (stratus)

On your blue paper, draw the different types of clouds (using chalk and charcoal).

*Use your textbook (pg. 111) and the cloud charts.*

Label each type of cloud.

Paste the paper into your science notebook.

Spot the cloud!

Low and flat …..

STRATUS

Middle level,

fluffy …..

Alto-Cumulus

Spot the cloud!

Spot the cloud!

High level, wispy …..

Cirrus

Spot the cloud!

Rain bearing, storm clouds …..

Cumulo-Nimbus

If you’re wearing a

black shirt on a

sunny day, you will

feel REALLY warm.

But if you’re wearing

white, you will stay

cooler.

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This is because dark

colors ABSORB

more sunlight than

lighter colors.

The air over

this part of

South

America

might be

cool…

While the air

over this part

is warmer.

This is called

UNEVEN

HEATING.

Cold air moves pretty slowly, and stays

pretty tightly packed together:

Hot air, on the other hand, goes really

fast and expands to fill more space.

So, hot air is LESS DENSE than cold

air.

• You should remember from our density column that less dense materials float

on more dense materials.

Closely packed for high density

Spread out for

low density

So, since hot air is less dense than the

surrounding air, it rises, leaving a low-

density, low-pressure area behind.

Low pressure

Nearby cold air can then rush in to fill low-

pressure area left by the rising hot air.

This rushing in of cold

air is what we call…

WIND!!

UNEVEN HEATING

The uneven heating of the air that causes

wind is created not only by different

colors on Earth’s surface, but also by:

• Different surfaces (grass vs. snow vs.

water, etc.)

• Pollution in some areas

• Different amounts of sunlight due to

seasons, clouds, etc.

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During the day, the air

over the sand is hotter

than the air over the

water because the

water takes longer to

heat up in the Sun.

So the wind in the

daytime blows

TOWARD the beach.

WARMER COOLER

But at night, the air over the

water is warmer than the air

over the sand, because

water HOLDS heat longer

than the ground.

So the wind blows toward

the ocean at night.

WARMERCOOLER

Sea Breeze

Land BreezeAir Masses

& Fronts

What is an AIR MASS?

• An air mass is a huge body of air that

influences weather.

• Scientists classify air masses based on:

TEMPERATURE and HUMIDITY

Air Masses are named based on where

they FORMED…

= TROPICAL

= POLAR

= MARITIME

(means sea… wet)

= CONTINENTAL

(means land… dry)

How are Air Masses named?

MARITIME

TROPICAL

MARITIME

POLAR

CONTINENTAL

TROPICAL

CONTINENTAL

POLAR

North American Air Masses

MARITIME

POLAR

CONTINENTAL

POLAR

MARITIME

POLAR

MARITIME

TROPICAL

MARITIME

TROPICAL

CONTINENTAL

TROPICAL

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How do these air masses move?

MARITIME

POLAR

CONTINENTAL

POLAR

MARITIME

POLAR

MARITIME

TROPICAL

MARITIME

TROPICAL

CONTINENTAL

TROPICAL

Jet Stream Jet Stream

Prevailing Westerlies

That’s why weather

generally moves

WEST to EAST

in the U.S.

What happens when air masses

meet?

• Air masses don’t mix easily.

• The line between air masses is called a

front.

COLD FRONTS

WARM FRONTSCompare/Contrast Chart - Types of Fronts

Front How it Forms Type of Weather

Cold

Front

A fast-moving cold air mass

overtakes a warm air mass.

Clouds form.

If warm air is humid,

rain/snow may fall.

Possible thunderstorms.

Warm Front A warm air mass overtakes

a slow-moving cold air

mass.

Scattered clouds.

Light rain or snow.

May last several days.

Stationary Front Cold and warm air meet,

but neither can move the

other. Creates “standoff”

Rain, snow, clouds, or fog

that may last for days.

Occluded Front A warm air mass is

caught between 2 cooler

air masses. Warm air

mass is pushed up.

Temperature gets

cooler.

Clouds and rain may

form.

Surface Map (Fronts & Precipitation)

Stationary Front

Occluded FrontWarm

Front

Cold Front

HHigh Pressure

LLow Pressure

Precipitation

Temperature Map

Stationary Front

Occluded FrontWarm

Front

Cold Front

HHigh Pressure

LLow Pressure

30°C

14°C

15°C

12°C

28°C 21°C

20°C

26°C

25°C

19°C

Monday Weather

Little Rock, AR

Sun & clear skies

Cool = 15°C

Tuesday Weather

Little Rock, AR

Clouds & Rain

Warmer = 21°C

Wednesday Weather

Little Rock, AR

Partly Sunny

Warmer = 26°C

Which direction is the warm

front moving?

What will happen to the

weather in Little Rock?

Stationary Front

Occluded FrontWarm

Front

Cold Front

HHigh Pressure

LLow Pressure

18°C

10°C

8°C

20°C

Thursday Weather

Nashville, TN

Partly Sunny

Warm = 20°C

15°C

11°C

10°C

10°C

Which direction is the

cold front moving?

What will happen to the

weather in Nashville?

Friday Weather

Nashville, TN

Thunderstorms

Cooler = 15°C

Saturday Weather

Nashville, TN

Sunny

Cool = 10°C

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Weather Tools

Thermometer

A thermometer uses an expanding liquid to

measure temperature.

Thermometer

► We will measure temperature using the Celcius scale.

Anemometer

► An anemometer measures wind speed.

Anemometer

► The unit we will use for wind speed is miles per hour (mph).

Hygrometer

► A hygrometer is used to measure humidity.

Hygrometer

►Humidity is measured in percents, where 100% would be the maximum amount of water the air can hold.

Barometer

► A barometer is used to measure air pressure.

Barometer

► The unit used for air pressure is the hectopascal (hPa). Normal atmospheric pressure is 1013.25 hPa.

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Severe WeatherThunderstorms, Tornadoes,

Hurricanes, etc…

What is Thunderstorm?

•A thunderstorm is a small storm often accompanied by heavy precipitation and frequent thunder and lightning.

•Many thunderstorms form in the spring and summer in southern states or on the Western Plains.

How does thunderstorms form?

Thunderstorms form in large cumulonimbus clouds also known as thunderheads on hot, humid afternoons or when warm air is forced upward along a cold front.

What is Lightning?

• Lightning is created by friction between the rising updraft and the falling downdraft in a cumulonimbus cloud

• This friction creates a separation of charges (kindalike rubbing your feet across the carpet in your socks)

• Eventually there is a discharge between positive and negative charges, creating a “spark” (kinda like touching that doorknob and getting a shock)

• On a larger scale, that “spark” is a bolt of lightning

What is Thunder?

• When lightning strikes, the “bolt” can be as hot as 30,000 degrees

• The air surrounding that bolt of electricity expands rapidly (remember… warm air expands), and then contract quickly as it cools.

• Because of the extremely high temperatures, the air expands and contracts rapidly and breaks the sound barrier (767 mph)

• The thunder is this “sonic boom.”

Thunderstorm Damage

• The heavy rains during thunderstorms can flood low-

lying areas. Floods can occur when

– the ground is already saturated by heavy rains.

– The water can’t soak into the areas covered with buildings, roads, and parking lots.

– A flash flood is a sudden, violent flood that occurs

shortly after a storm.

• When lightning strikes the ground, the hot,

expanding air can shatter tree trunks or start forest fires.

• Stay out of water because it’s a great conductor of electricity.

Can you tell how far away a storm is?

• Yes, you can use thunder to tell how far away a storm is. Next time you see a storm, count the number of seconds between when you see the lightning and hear the thunder. Take the number of seconds and divide by 5 and that will tell you how far away the storm is in miles. For example: If you counted 10 seconds between the lightning and the thunder, the lightning is 2 miles away!

HailHail is created when small water droplets are caught in the updraft of a thunderstorm. These water droplets are lifted higher and higher into the sky until they freeze into ice. Once they become heavy, they will start to fall.

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SEVERE THUNDERSTORM WATCH - A severe

thunderstorm (damaging winds of 58 miles per hour or more, or 1" hail in diameter or greater) is

likely to develop

SEVERE THUNDERSTORM WARNING - A severe

thunderstorm (damaging winds of 58 miles per hour or more, or hail three-fourths of an inch in

diameter or greater) is taking place in your area.

DOWNDRAFT - A sudden descent of cool or cold air to

the ground, usually with precipitation, and associated with a thunderstorm or shower.

UPDRAFT - A warm column of air that rises within a

cloud. If the air is sufficiently moist, then the moisture condenses to become a cumulus cloud.

Tornadoes

Thought to be the 1st photograph of a tornado (1884)

What are Tornadoes?

• Violent windstorms that take the form of a rotating column of air, or vortex, that extends downward from a cumulonimbus cloud.

• Because of the lower pressure in the center vortex, air near the ground rushes into the tornado from all directions.

• Air streams inward, it is spiraled upward around the core until it eventually merges with the airflow or the parent thunderstorm deep in a cumulonimbus tower.

How does Tornado

Form?

When warm, moist air mass

from the Gulf of Mexico meets cool, dry air mass from

Canada, they create instability in

the atmosphere. A change in wind

direction and an increase in wind

speed with increasing height creates

an invisible, and horizontal spinning effect in the lower

atmosphere. Rising air within the

updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation

Tornado Alley

• Tornadoes occur more often in the United States than in any other country.

• About 800 tornadoes occur in the United States every year.

• Weather patterns on the Great Plains result in a “tornado alley.”

• Tornado Alley states: Arkansas, Iowa, Kansas, Louisiana, Missouri, Nebraska, New Mexico, Oklahoma, South Dakota, Texas

Watches & Warnings

• Tornado Watch

–Conditions are ideal for a tornado to be created.

• Tornado Warning

–An actual tornado has been sighted in the area or is indicated by weather radar.

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Tornado Safety Tips• BEFORE A TORNADO:

– Have a disaster plan. Prepare a kit with

emergency food for your home.

– Have enough food and water for at least 3

days.

• DURING A TORNADO:

– Go to a basement, bathroom, closet, or under

a table

– Leave mobile homes and go to a shelter

– Leave automobiles and do not try to outrun a

tornado.

– If outside, go to a ditch or low lying area and lie flat

– Stay away from fallen power lines and any damaged areas.

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Tornado Safety Tips• AT SCHOOL DURING A TORNADO:

– All schools have a disaster plan, and

frequent drills.

– Go to school’s basement or rooms

and hallways away from windows

– Crouch down on your knees and protect your head with your arms.

• AFTER A TORNADO:

– Stay indoors until it is safe to come out.

– Check for injured or trapped people, without putting yourself in danger

– Watch for downed power lines

– Use a flashlight to inspect your home.

“What’s in our Air?”

We breathe constantly… without thinking about it.

But not everything in our air is healthful… there can be

harmful substances in our air called POLLUTANTS.

Air Pollution is a problem!Where does Air Pollution come from?

Some sources of air pollution are natural, but most air pollution is the result of human activities.

Natural Sources = ►Forest Fires

►Volcanoes

►Sand Storms

Which human activities release air pollution?

Burning Fossil Fuels

(such as coal, oil, gasoline, diesel fuel)

50% from cars and other motor vehicles

50% from factories, power plants and other sources.

Major Air Pollutants & their Effects

POLLUTANT EFFECTS

Carbon Monoxide illness, death

Nitrogen Dioxide breathing problems, lung damage

Sulfur Dioxide acid rain, breathing problems

Particulate Matter breathing problems, throat irritation

Ozone smog, asthma

How do youcontribute to air pollution?

OUR Impact on Air Quality…

The cup of water in front of you represents unpolluted, clean air.

You’ll add drops of food coloringto represent the different types of air pollutants caused by everyday activities.

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OUR Impact on Air Quality…

BLUE – pollutants from consumer products & paints

GREEN – pollutants from lawn, garden, and construction machinery

RED – pollutants from cars & trucks

YELLOW – pollutants from power plants & factories

OUR Impact on Air Quality…1) Look inside your cup. If the air pollution

around you were this visible, would you want to breathe the air?

2) Are there other sources of air pollution you might have contributed to?

3) What could you do to reduce the pollutants in the air?

4) What is the combined effect of each person’s pollution?

That’s a lot of info… Let’s look at 3 pollutants

in greater detail:Sulfur Dioxide

Particulate MatterOzone

Sulfur Dioxide causes acid rain… yikes!►Pollutants in the air combine with water in the

atmosphere and form acids.

►That acid gets in our rain/snow and falls back to earth, harming our lakes & ponds, and all the organisms that live there.

What is particulate matter?►Tiny particles of dust and smoke in the air.

►These particles make it

hard to breathe. (especially for older folks and young kids)

►These particles also cause haze and reduce visibility.

View of Chicago on 2 different days

(one clear, one hazy) Chicago - Summer 2000.

Clear Day : PM 2.5 < 5 µg/m3

Clear Day in Chicago, Summer 2000

Chicago - Summer 2000.Hazy Day : PM 2.5 = 35 µg/m3

Hazy Day in Chicago, Summer 2000Wait – isn’t OZONE a good thing?

►The ozone layer in the stratosphereprotects us. GOOD

►BUT ground-level ozone makes SMOG. BAD

(an UNHEALTHY brown haze)

Atlanta

Particulate Matter & Smog in Atlanta

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How can you protect yourself from air pollution?

• Check your local Air Quality Index (AQI) every day.

• The AQI is a color-coded system that tells you how clean the air is.

Good

Moderate

Unhealthy

for sensitive

groups

Unhealthy

Very

Unhealthy

Hazardous

What time of day has the worst air quality?

Interesting Air Pollution

Facts…

Air Pollution can travel far…

What goes around …comes around

Forest fire smoke

drifts across Florida

PM & CO2 drift from Asia to U.S.

Clouds

Smog

Air Pollution kills people…

Annual Deaths due to:

Air Pollution = 23,000

Drunk Driving = 17,000

Murder = 20,000

North Carolina summers are not good for your health!

In NC, air pollution causes an EXTRA:

240,000 Asthma Attacks

6,300 ER Visits

The “Worst 25” Cities for OzoneAtlanta 6th

Knoxville 8th

Charlotte 9th

Raleigh-Durham 13th

Nashville 18th

Memphis 19th

New York 20th

Birmingham 21st

Greensboro-Winston 21st

Macon 24th

Chattanooga 24th

Let’s take a closer look at particulate

matter…

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Airborne Junk1) In your science notebook, write the

following question:

What does particulate matter look like?

2) Examine the samples with the magnifying lenses and stereoscopes.

3) Draw what you see for 2 samples. Be sure to note where the samples came from…

Airborne JunkIn your science notebook, answer the conclusion questions:

1) Which locations had the most particulate matter?

2) Which locations had the least particulate matter?

3) Why would certain locations have more than others? EXPLAIN!