The Atmosphere Ch. 3 sec. 2

atmosphere Mixture of gases surrounding the Earth

Atmosphere 78% nitrogen 21% oxygen 1% other (argon, carbon dioxide, methane, and water vapor)

Where do gases come from Animals – cellular respiration Plants - Photosynthesis

Where do gases come from Volcanic eruptions Vehicles industries

Particles in the Atmosphere Atmospheric dust – salt, ash from fires, volcanic ash, skin, hair, pollen, bacteria, viruses

Insulation Atmosphere insulates the Earth Slows the loss of heat Maintains temp.

Layers of Atmosphere Troposphere Stratosphere Mesosphere Thermosphere

Troposphere Nearest to the Earth Weather occurs in this layer Densest layer

Stratosphere Extends from 18km to 50km Temp. rises Ozone layer – O3 (absorbs UV rays)

Mesosphere 50Km -80Km Coldest layer

Thermosphere Farthest from Earth Hottest layer (nitrogen and oxygen absorb solar radiation)

Aurora - Northern lights Nitrogen and Oxygen atoms absorb X rays and gamma rays Causes them to become charged (ions)

Energy in the Atmosphere Energy from sun is transferred: Radiation Conduction Convection

Radiation Transfer of energy in the atmosphere Standing by a fire

Conduction Flow of heat from a warmer object to a colder object by direct contact Pan on a stove

Convection Transfer of heat by air currents Convection oven, heater in house/car

Heating of Atmosphere Half of solar energy that enters the atmosphere passes through and reaches Earth’s surface Absorbed or reflected by clouds, gases

Heating of Atmosphere Oceans and land radiate energy back into atmosphere

Heating of atmosphere Darker objects absorb more solar radiation than lighter objects

Movement of energy Air movements cause our weather Warm air rises and cold air sinks

Convection Currents The continual process of warm air rising and cool air sinking in a circular motion is called Convection Currents

Greenhouse Gases Gases in the air trap heat that is being reflected back from the Earth Heat is absorbed which warms the air