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Atmosphere . 6 th Grade Science Mrs. Hutchcroft. Solar Energy as Radiation. Figure 1.1. Nearly 150 million kilometers separate the sun and earth, yet solar radiation drives earth's weather. Earth's Atmosphere. Thin Gaseous envelope. Figure 1.2.

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6th Grade Science

Mrs. Hutchcroft


Solar Energy as Radiation

Figure 1.1

Nearly 150 million kilometers separate the sun and earth, yet solar radiation drives earth's weather.


Earth's Atmosphere

Thin Gaseous envelope

Figure 1.2

The atmosphere is a thin layer of air that protects the Earth’s surface from extreme temperatures and harmful sun rays

composition of atmosphere mixture of gases solids and liquids
Composition of Atmosphere(Mixture of gases, solids, and liquids)
  • Early atmosphere was much different than today
    • Volcanoes produced nitrogen and carbon dioxide, but little oxygen
    • More than 2 billion years ago, early organisms began producing oxygen
    • Eventually, oxygen formed an ozone layer that protected Earth from harmful rays
    • Green plants and diverse life forms developed
atmospheric gases mixture of gases solids and liquids
Atmospheric Gases(Mixture of gases, solids, and liquids)
  • Nitrogen - 78%
  • Oxygen - 21%
  • Water Vapor – 0 to 4%
    • Used for clouds and precipitation
  • Carbon Dioxide - .037%
    • Keeps Earth warm and is used by plants to make food
  • Argon - .93%
  • Traces of neon, helium, methane, krypton, xenon, hydrogen, and ozone
atmospheric gases mixture of gases solids and liquids1
Atmospheric Gases(Mixture of gases, solids, and liquids)
  • Atmosphere is changing with the introduction of pollutants; increasing human energy use is increasing the amount of carbon dioxide
  • Pollutants mix with oxygen and other chemicals to form smog
    • Aerosols include solids such as dust, salt, and pollen
    • Liquids include water droplets and droplets from volcanoes
lower layers of atmosphere
Lower Layers of Atmosphere
  • Troposphere: lowest layer – extends up to 10km; contains 99% of the water vapor and 75% of the atmospheric gases
  • The troposphere is the first layer above the surface and contains most clouds and half of the Earth's atmosphere.
    • Weather occurs in this layer.
    • Most of the layer’s heat is from Earth
    • Temperature cools about 6.5 degrees Celsius per kilometer of altitude.
lower layers of atmosphere1
Lower Layers of Atmosphere
  • Stratosphere – directly above troposphere, extending from 10 km to about 50 km above Earth’s surface
    • Portion of the upper layer contains high levels of a gas called ozone
    • Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun.
upper layers of atmosphere
Upper Layers of Atmosphere
  • Mesosphere – extends from the top of the stratosphere to about 85 km above Earth
    • Coldest layer with little ozone
    • Meteors or rock fragments burn up in the mesosphere.
    • Ionosphere here – layer of charged particles
upper layers of atmosphere1
Upper Layers of Atmosphere
  • Thermosphere – thickest atmospheric layer found between 85 km and 500 km above Earth’s surface
  • The thermosphere is a layer with auroras, known for its high temperatures.
    • Warms as it filters out X-rays and gamma rays from the Sun
    • Ionosphere here, too – help carry radio waves.
upper layers of atmosphere2
Upper Layers of Atmosphere
  • Exosphere - The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere.
  • Outer layer where space shuttle orbits.
atmospheric pressure
Atmospheric Pressure
  • Molecules closer to the surface are more densely packed (at higher pressure) together than those higher in the atmosphere because of the mass of gases pressing down on them from higher in the atmosphere
temperature in atmospheric layers
Temperature in atmospheric layers
  • The troposphere is warmed primarily by the Earth’s surface; temperature decreases as altitude increases in this layer.
  • Temperatures increase as altitude increases in the stratosphere, particularly in the upper portion – ozone
  • Temperatures decrease with altitude in the mesosphere
  • Thermosphere and exosphere are the first to receive Sun’s rays, so they are very hot
the ozone layer
The Ozone Layer
  • About 19 km to 48 km above Earth in the stratosphere (90%) and troposphere (10%).
  • Layer of 3-atom molecules that protects the Earth from the Sun’s harmful ultraviolet radiation
  • Life depends on the ozone!
  • Pollutants called chlorofluorocarbons (CFCs) are destroying the ozone
  • CFCs are used in refrigerators, air conditioners, aerosol sprays, and foam packaging ~ if products leak, CFCs enter atmosphere
  • Ozone layers has a large hole over Antarctica and a smaller one over the North Pole

Solar energy

  • Some of the Sun’s energy coming through Earth’s atmosphere is reflected or absorbed by gases and/or clouds in the atmosphere.

Solar energy

Greenhouse Effect

  • Solar energy that is absorbed by the Earth’s land and water is changed to heat that moves/radiates back into the atmosphere (troposphere) where gases absorb the heat, a process known as the greenhouse effect.
global warming
Global Warming
  • Effects of Global Warming on Wildlife
  • Global Warming VIDEO
  • Global Warming VIDEO #2
  • Energy that flows from an object with a higher temperature to an object with a lower temperature
  • Heat is transferred through the atmosphere by:
    • Radiation:energy that is transferred in the form of rays or waves
    • Conduction:energy that is transferred when molecules bump into each other
    • Convection:energy that is transferred by flow of material
      • Molecules move closer together, making air more dense, and air pressure increases
      • Cold air sinks, pushing up warm air, which then cools and sinks, pushing up more warm air
water cycle video link
Water Cycle Video Link
  • Water moves back and forth between Earth’s atmosphere and surface
  • Energy from the sun causes water to evaporate from the hydrosphere and rise as vapor
    • Sun provides water cycle’s energy
    • Water on the surface absorbs heat and evaporates, entering the atmosphere
    • Condensation – water vapor changes back into liquid
    • Clouds of water become heavy and water falls to Earth as precipitation
    • The cycle repeats itself continuously


  • Rain & Drizzle- most common type of precipitation.
  • Freezing Rain- drizzle from stratus clouds.
  • Freezing Rain- raindrops freeze when they hit the ground.
  • Sleet- raindrops that freeze before they hit the ground.

Waters 3 States Video6:52



  • snow- as ice grows and merges into clouds they form snowflakes.
  • hail- is the largest type of precipitation.
  • Lumps or balls of ice that fall from cumulonimbus clouds in warm weather.

The Sun, Water Cycle, & Climate Video2:37

The Water Cycle and Clouds Video 15:01

what is weather
What is Weather?
  • State of the atmosphere at a specific time and place
  • Includes such conditions as air pressure, wind, temperature, and moisture in the air
  • Temperature is a measure of air molecule movement
    • Sun’s energy causes air molecules to move rapidly; temperatures are high and it feels warm
    • When less of the Sun’s energy reaches air molecules, they move less rapidly and it feels cold
what is weather1
What is Weather?
  • Energy is transferred between fast-moving molecules and slower-moving molecules
    • CONDUCTION – transfer of energy when molecules collide
    • CONVECTION – occurs when warm air rises and cool air sinks; it’s the transfer of heat, usually in liquids or gases
If we were to pick one term to help explain why we have weather, what do you think would be a good word?

You might pick heat or sun….but another good choice would be


After the atmosphere is warmed by radiation and conduction, the heat is transferred throughout the atmosphere by convection.
  • Since warmed air has more space between the molecules, it’s less dense and rises
  • Cooled air is more dense and tends to sink
  • In general, air near the equator tends to rise and air near the poles tends to sink
notice the band of clouds around the equator

Notice the band of clouds around the equator ?

This is the ITCZ or inter tropical convergence zone

did you figure it out
Did you figure it out?
  • Warm, moist air in the tropics rises
  • Cold air can hold less moisture than warm air
  • As the moist air rises, it condenses and forms clouds!
now what
Now What?
  • Ok, so we know that the weather moves around on these highways and that warm air rises and cold air sinks.
  • But why is it sunny one day, and rainy the next?
let s take another look at the weather map
Let’s take another look at the weather map
  • Notice that there are H’s and L’s on the map
  • There are also blue lines with spikes and red lines with half circles
  • Let’s take a closer look!
air pressure
  • Air weight that varies over Earth’s surface
    • Warmer air is less dense and exerts less pressure
    • Cooler air is more dense and exerts more pressure
high pressure areas
High Pressure Areas
  • When cooler air sinks and is warmed, the air can hold more moisture
  • This usually means sunny skies
  • Winds tend to move clockwise around a high
low pressure areas
Low Pressure Areas
  • When warm air rises and is cooled, the air can not hold as much moisture
  • Often, these areas are associated with precipitation and stormy weather
  • Winds tend to move counter clockwise around the low
  • The amount of water vapor in the air
  • Temperature affects how much moisture is in the air - warmer air can hold more water vapor, tending to make it more humid
  • Relative humidity – the amount of water vapor in the air compared to what it can hold at a specific temperature
  • When air cools, it can’t hold as much water vapor, so the water vapor condenses to liquid or forms ice crystals
  • Dew point – the temperature at which air is saturated and condensation forms
  • Form when air rises, cools to its dew point, and becomes saturated
  • Shape and height of clouds vary with temperature, pressure, and water vapor in atmosphere
  • Shape
    • Stratus-smooth, even sheets or layers at low altitudes
    • Cumulus-puffy, white clouds, often with flat bases
    • Cirrus-high, thin, white feathery clouds made of ice crystals
  • Height
    • Cirro – high clouds
    • Alto – middle-elevation clouds
    • Strato – low clouds
    • Nimbus clouds are dark and so full of water that sunlight can’t penetrate them
  • LOW CLOUDS – form at 2,000 m or less in altitude
    • Cumulus – puffy clouds formed when air currents rise and carry moisture
    • Stratus – layered dull, gray sheets that can cover the entire sky
    • Nimbostratus – low, dark, thick layers that hide the Sun



· Clouds formed at medium or low elevation.

· Cumulus clouds are puffy with flat bottoms.

· When cumulus clouds are white they often signal fair weather, but when they are darker, they may signal rain or thunderstorms.



  • Stratus
  • Clouds formed at medium or low elevation; spread out layer upon layer covering a large area
  • As stratus clouds thicken, precipitation usually occurs over that area.
  • MIDDLE CLOUDS – form between 2,000 m and 8,000 m in altitude
    • Most are layered
    • Names have alto- prefix (altocumulus and altostratus)
    • Can produce light precipitation
    • Cirrus – wispy, high-level clouds
    • Cirrostratus – high, layered clouds that can cover the sky
    • Cumulonimbus – known as thunderstorm clouds; produce heavy precipitation


  • Cirrus
  • Clouds formed at high elevations; wispy clouds usually consisting of ice crystals that signal fair weather or may also signal an approaching warm front.






Cloud Cover Symbols

  • You will often see the circles drawn on a weather map
air movement
Air Movement
  • Wind: Movement of air from one temperature or pressure area to another
  • Different areas of Earth receive different amounts of the Sun’s energy
    • Equator’s warm air, being less dense, is pushed upward by denser, colder air
    • Poles’ cold air, being more dense, sinks and moves along Earth’s surface
    • CORIOLIS EFFECT: spinning of the Earth causes moving air to turn to the right in the northern hemisphere and to the left in the southern hemisphere
global winds
Global Winds
  • Wind patterns, caused by convection currents combined with the Coriolis effect, of Earth that affect the world’s weather
    • Near equator, very little wind and daily rain patterns called the doldrums
    • Surface winds:
      • Between equator and 30 degrees N and S latitude are steady trade winds
      • Between 30 and 60 degrees N and S latitude, the westerlies blow in opposite direction from the trade winds.
      • The polar easterlies blow from northeast to southwest near the north pole and from southeast to northwest near the south pole

Global Winds


Equatorial doldrums


the weather highways
The Weather Highways
  • The rotation of the earth creates the Coriolis effect.
  • The Coriolis effect causes the air and water to be deflected to the right north of the equator.
  • This creates global weather highways
the westerlies
The Westerlies
  • Because of our latitude, most of our weather comes from the west
  • Looking at the weather map, what type of weather might we expect?
  • What type of weather might we expect in a few days?
let s break for a short review
Let’s break for a short review

1.Transfer of heat in liquids or gases_____

2. _____ air is dense and tends to sink.

3. Band of clouds found around the equator______

4. Cold air holds _____ moisture than warm air

5. The Coriolis effect causes the air and water to be deflected to the _____ of the equator

how did you do
How did you do?






fronts and air masses
Fronts and Air Masses
  • Because air and moisture move in the atmosphere, weather is constantly changing
  • Air pressure – measured by barometer
  • An air mass is a large body of air whose temperature and moisture are fairly similar at a given altitude; properties like the part of Earth’s surface over which it formed
  • Fronts are boundaries separating different air masses – clouds, precipitation, and storms occur at frontal boundaries
  • There are four different air masses that affect the United States
the air masses
The Air Masses
  • cP( continental polar) : cold, dry stable
  • cT( continental tropical) : hot, dry, stable air aloft, unstable at the surface
  • mP( maritime polar) : cool, moist, unstable
  • mT( maritime tropical) : warm, moist, unstable
warm fronts
Warm Fronts
  • A warm front is warm air displacing cool air
  • Shallow leading edge warm air must “overrun” cold air
  • These are usually slow moving

Widespread precipitation develops!


Warm Front

2.Warm Front: The zone where warm air is replacing colder air

  • In U.S., warm fronts usually move from southwest to northeast
  • Air gets more humid after a warm front moves through
cold fronts
Cold Fronts
  • Cold air advances into region of warm air
  • Intensity of precipitation greater, but short lived
  • Clearing conditions after front passes
  • Usually approaches from W or NW

Temperature drops; narrow band of violent storms!


Cold Front

1.Cold Front: The zone where cold air is replacing warmer air

  • In U.S., cold fronts usually move from northwest to southeast
  • Air gets drier after a cold front moves through
stationary fronts
Stationary Fronts
  • Surface positions of the front do not move
  • Often a region of clouds and precipitation

Stationary Front

3.Stationary Front: When either a cold or warm front stops moving

  • When the front starts moving again it returns to either being a cold or warm front
occluded fronts
Occluded Fronts
  • Cold front overtakes warm front
  • Involves three air masses of different temperatures
  • Often found

close to the low pressure center

Cloudy weather with precipitation!



Occluded Front

4.Occluded Front: Formed when a cold front overtakes a warm front

  • This occurrence usually results in storms over an area
  • In U.S., the colder air usually lies to the west
  • Winds in a low pressure system move _____ around the low
  • What type of front can be found close to point D?
  • Which of these fronts would you expect to have greater precipitation, but be short lived as the front passes?
  • Give the name of the air mass that would have the following characteristics:
  • cool, moist, unstable

It causes air and water to be deflected to the right north of the equator


Warm air holds ( more or less ) moisture than cold air

  • If there is a bigH on the weather map where you live, would you expect fair or stormy weather
how did you do1
How did you do?

Let’s check the answers!


1. Counterclockwise 8. Westerlies

2. Cold 9. More

3. Cold 10. Fair

4. Maritime polar (mP)

5. Convection

6. Rise

7. Coriolis


Weather Tools

Anemometer- A tool used to measure

wind speed in miles per hour.

Wind vane

· A tool used to measure wind direction.

· Sometimes referred to as a

wind-weather vane or a wind sock.

· Wind direction is described by the direction from which the wind is blowing.

Thermometer - A tool used to measure air temperature in degrees Fahrenheit or Celsius.


Weather Tools

  • Sling Psychrometer-
  • A two-thermometer instrument also referred to as a wet-dry bulb used to measure relative humidity (the amount of water vapor in the air).
  • Temperatures readings are converted using a relative humidity table.

Weather Instruments Video 115:01

Weather Instruments Video 219:41


Weather Tools

Barometer- A tool used to measure air pressure in inches of mercury or millibars (mb).

Rain gauge- A tool used for measuring the amount of precipitation in inches or centimeters.

reading a weather map
Reading a weather map

ISOBAR= connects areas of equal pressure BAR comes from BARometric pressure

reading a weather map1
Reading a weather map...

Isotherm: Connects areas of equal temperature; therm means temperature


Station Models

  • Information found on a station model can include cloud cover, temperature (85°F), wind direction and speed, precipitation (snow, rain), or barometric pressure (1002 mb).
  • Station models from specific locations provide information that can also be used to predict weather patterns.
weather station not on the tv weather conditions at specific location
Weather Station (not on the TV)Weather conditions at specific location

Current Conditions!!


Satellites & Radar


· Satellite images are used for seeing cloud patterns and movements.

· For example, hurricane clouds and movement can be observed using satellite images.


· Radar images can be used to detect cloud cover, rainfall or storm location, intensity, and movement, as well as the potential for severe weather (for example, hurricanes or tornadoes).

severe weather
Severe Weather
  • Thunderstorms occur inside warm, moist air masses and at fronts
    • Warm, moist air is forced rapidly upward, where it cools and condenses
    • Strong updrafts of warm air and sinking, rain-cooled air cause strong winds
  • Movement of air inside a storm cloud causes parts of the cloud to become oppositely charged
  • Current flows between the regions of opposite electrical charge, forming a lightning bolt
  • Thunder – lightning superheats the air, causing it to expand rapidly and then contract, forming sound waves
  • Violent, whirling wind that moves in a narrow path over land
  • Large, swirling, low-pressure system that forms over tropical oceans
  • Heat energy from moist air is converted to wind that can reach speeds of 250 km/h
  • A winter storm with strong winds, cold temperatures, and low visibility, that lasts more than three hours
severe weather safety
Severe Weather Safety
  • A National Weather Service WATCH means conditions are favorable for severe weather to develop
  • A warning means that severe weather conditions already exist
  • Meteorologists study and predict weather
  • National Weather Service makes weather maps and issues watches and warnings