1. The Atmosphere Chapter 17.1
What is the atmosphere? A blanket of gases that surrounds Earth.
Can these gases be seen? No
Felt? Yes,,,as wind

2. Lesson Objectives Identify the major components of Earth’s atmosphere
Explain how air pressure changes with altitude
Explain how temperature changes with altitude
Describe the layers of the atmosphere
Explain how the processes of radiation, conduction and convection distribute energy in the atmosphere

3. What is Air?
A mixture of gases and particles each with their own properties
Nitrogen and Oxygen make up 99% of the volume of air
Argon gas %
CO %
Also contains: H2O vapor, ice, dust particles, hydrogen, salt and ozone

4. Structure of the Atmosphere
The Atmosphere is made up of 5 different layers.
Each layer is different in composition and temperature
It is thickest near the surface of Earth and thins out with height until it eventually merges with space.

6. Layers of the Atmosphere- Troposphere
Closest to Earth surface
Contains most of the mass of the atmosphere
Weather takes place
Pollution collects
There is a decrease in temperature as you travel up the Troposphere
Lapse Rate
The upper-limit of the Troposphere is called the Tropopause
Densest layer Lapse Rate = temp decreases by about 6.5 degree C for every km of altitude
Airplanes fly in this layer Almost all of the CO2, water vapor, clouds, and life occur here
~16 km above earth’s surface in tropics ~ 9 km at poles Troposphere means “Sphere of change” it is constantly changing

7. Layers of the Atmosphere- Stratosphere
Located above the Tropopause
Made up primarily of concentrated ozone
Ozone absorbs ultraviolet radiation from the sun
So…what do you think happens here in terms of temperature?
The top of the Stratosphere is called the Stratopause
Many jet aircrafts fly in this layer because it is very stable % of the mass of Earth’s atmosphere is below the stratopause
Extends up to 50 km
Ozone is created here

8. Layers of the Atmosphere- Mesosphere
Located above the Stratopause
No ozone …so what happens to the temperature?
Top of the Mesosphere is called the ……
Meteors burn up in this portion of the atmosphere
Coldest part of the atmosphere -93degree C
km above earth’s surface

9. Layers of the Atmosphere- Thermosphere
Contains only a minute portion of the atmosphere’s mass
Air that does exist in this layer increases in temperature to more than 1000°C
Ionosphere is with thermosphere
Nitrogen and oxygen atoms absorb harmful solar energy…X-rays and gamma rays
Causes the high temperatures
Gas particles lose electrons and become ions
Auroras- Northern and Southern Lights occur
The molecules that make up the air are so sparse and widely spaced that despite the high temperature this layer would not seem warm to human passing though it
The charged particles in the ionosphere reflect radio waves emitted from Earths’ surface….helping transmit radio signals around the world
Layer between 100 km and 500 km above Earth’s surface

11. Layers of the Atmosphere- Exosphere
Outermost layer of the atmosphere
Lighter elements are found in this layer
Above the Exosphere is outer space
Hydrogen and Helium km to 10000km above Earth’s surface
There is no clear boundary between the atmosphere and space-just fewer and fewer molecules with increasing altitude
Satellites orbit here without being slowed by friction

14. Solar Fundamentals
The sun is the source of all of the energy in the atmosphere
This energy is transferred to the Earth and throughout the atmosphere by convection, conduction and radiation

15. Heat Transfer Convection Conduction
The transfer of energy by the flow of a heated substance
Responsible for the vertical motions of air, which causes different types of weather
Works based on density
Conduction
Transfer of energy that occurs when molecules collide
Affects only a very thin atmospheric layer near Earth’s surface

16. Heat Transfer Radiation
Transfer of energy through space by visible light, UV radiation and other forms of electromagnetic waves
Earth’s surface absorbs the solar radiation and then radiates energy with longer wavelengths, which warm the atmosphere through convection and conduction