1. The Atmosphere
The Air Around You
Weather- condition of Earth’s atmosphere at a particular time and place
Atmosphere-the envelope of gases that surrounds the
planet
Earth’s atmosphere =
N most abundant gas, ~75% of air we
breathe
O nd most abundant, ~21%
Together these two make up 99% of dry air, remain
gases = trace gases, most of other 1% is Argon
CO2 - less than 1% , but is essential
THESE ARE ALL PART OF DRY AIR, BUT AIR IS NOT DRY!
H2O vapor – invisible, varies from place to place and from time to time, important role in weather ie. clouds = water vapor condensing, if drops get heavy enough we get rain or snow
Particles – dust, smoke, salt, chemicals, pure air only exists in labs
The Atmosphere is a system, events in one part affect others
Parts = clouds, air, wind, energy

2. Layers of the Atmosphere
Four Main Layers-based on temp. change
Troposphere-tropo = turning or changing
Weather occurs here
Variable conditions
~12 km thick, can be 9 above poles, 16km above
equator
Most dense, contains most of the mass of the
atmosphere
As altitude increases temp decreases
Stratosphere- strato = layer or spread out
Top of tropo to about 50 km above surface of Earth
Contains ozone (O3)
Ozone protects living things from UV radiation
Temperature increases with altitude- due to ozone layer

3. Layers of the Atmosphere
Mesosphere- meso = middle
Temp decreases
50-80km above Earth’s surface
Upper mesosphere -900C
Protects earth from meteoroids
meteors collide with the gas particles present in the
mesosphere and burn
Thermosphere- outermost layer
80 km outward into space, no definite outer limit
Temp increases
Since sunlight strikes this layer, temp up to
1800oC, BUT doesn’t feel hot because particles are very,
very far apart so they do not collide with things to transfer energy.
Ionosphere-
km from surface
Exosphere-
400- thousand km’s outward

4. Layers of the Atmosphere
Changing Temperatures
The graph shows how temperatures in the atmosphere change with altitude.

5. The Atmosphere Air has the following properties
Air Pressure
Air has the following properties
Mass
Density
Pressure – force pushing on and area or surface
Air pressure – weight of a column of air pushing on an area
Barometer- instrument used to measure air pressure
Mercury- contains glass tube, like thermometer, when air pressure increases mercury in tube rises
Aneroid-(without liquid) dial connected with spring and levers, chamber shape changes due to pressure, dial moves
Units of pressure
Atmosphere (atm)
Inches of mercury
Millibars
1 atm = 1 bar
One inch mercury = millibars
30 inches of mercury = ? Millibars?
Effect of altitude on pressure and
density:
As altitude Air pressure
As altitude Density
Effect of Altitude on Pressure and Density
How densely packed would the molecules be at the different altitudes?

6. Energy is Earth’s Atmosphere
The Atmosphere
Energy is Earth’s Atmosphere
Electromagnetic (EM) waves-energy that can travel through a vacuum (space)
Classified according to wavelength
Most energy from sun comes in form of
Visible light-ROGBIV Red /Orange longest wavelength Blue/Violet shortest wavelength
Infrared radiation- not visible, longer wavelength than red light
Ultraviolet radiation- not visible, shorter wavelength than violet, causes sunburns
Energy in the Atmosphere
Some wavelengths reach Earth’s surface.
Other wavelengths are completely or partially
absorbed in the atmosphere.
Radiation From the Sun
Energy travels to Earth as electromagnetic waves. What are the types of electromagnetic radiation in the diagram?

7. Energy in Earth’s Atmosphere
The Atmosphere
Energy in Earth’s Atmosphere
Scattering- reflection of light in
all directions
Gas molecules in atmosphere scatter
short wavelengths of visible light more
than long wavelengths
This is why the sky is blue
Energy at Earth’s Surface
Complete each sentence with a word from the Word Bank to learn what is happening to the energy at Earth's surface and in the lower atmosphere.

8. Energy in Earth’s Atmosphere
The Atmosphere
Energy in Earth’s Atmosphere
The Greenhouse effect- natural process that keeps Earth’s temperature stable and comfortable for most living things
There is evidence that human activities are altering this process
Greenhouse Effect
The greenhouse effect is a natural heat-trapping process. What is the sequence of events that causes it to occur?

9. The Atmosphere
Heat Transfer
Temperature- average kinetic energy of particles in a substance
Measured with a thermometer
Thermal energy –total kinetic energy of all particles in a substance
Tea in pot vs. tea in a cup…
Which has higher temp?
Which has higher thermal energy?
Temp Scale
Celsius- 0 = freezing, 100 = boiling
Fahrenheit- 32 = freezing, 212 = boiling
Convert
Fahrenheit to Celsius C= (F-32) x 5/9
Celsius to Fahrenheit F= C x 9/5 +32
Heat- thermal energy transferred from
hot to cold
Conduction
Convection
Radiation
These three processes work together to heat troposphere

10. The Atmosphere
Winds
Unequal heating of atmosphere differences in pressure wind
Wind- movement of air parallel to Earth’s surface
Described by
Direction – measure by wind vane, name tells you what direction wind came from (south wind blows from South to North)
Speed-anemometer
Windchill factor- increased cooling that wind can cause
Local Winds
Sea Breeze-occurs during the day,
land warms up faster than water,
warm, less dense air rises creating low
pressure area, cool air blows inland
from the water
Land Breeze-occurs during the night,
water stay warm longer than land,
air above it is less dense so it rises,
cool air from the land blows out toward
water

11. The Atmosphere Global Winds
Winds that blow steadily from specific directions over long distances, also caused by diff. in pressure
See diagram on p. 446 for example of unequal heating
How do global winds develop?
Temp. differences between poles and equator produce giant convection currents= Global convection currents
Air pressure lower near the equator and greater near the poles
Winds at Earth’s surface blow from poles toward equator
Higher in the atmosphere, air flows away from equator toward poles – this produces global winds

12. The Atmosphere The Coriolis Effect
The curving of the global winds due to the rotation of the Earth
If the Earth did not rotate the winds would blow straight
Wind in northern hemisphere turn right
Wind in southern hemisphere curve left
Global wind belts
Doldrums- equator, calm area where warm air rises
Horse latitudes-30oN and S, calm area of sinking air
Trade winds-30oN and S to equator , toward equator
Prevailing westerlies-30-60oN and S latitude, away from equator
Polar Easterlies- 0-30o N and S latitude, away from poles

13. The Atmosphere