Chapter 15 Atmosphere Notes
The Air Around You Weather: The condition of the Earth s atmosphere at a particular time and place
The Air Around You Atmosphere: the envelope of gases that surround the planet
Composition of the Atmosphere The atmosphere is made up of a mixture of atoms and molecules of different elements
Composition of the Atmosphere Nitrogen: Most Abundant Gas in the atmosphere 78% of air we breathe
Composition of the Atmosphere Oxygen: 2 nd most Abundant Gas 21% of air Involved in important processes Plants and animals take it to live Fuels use it to burn Iron and steel form rust
Composition of the Atmosphere Ozone: 3 oxygen atoms Protects earth from UV Rays Like an umbrella
Composition of the Atmosphere Carbon Dioxide Plants need it to produce food Photosynthesis Animals give off CO 2 (Carbon Dioxide)
Composition of the Atmosphere Fuels like coal and gasoline release CO 2 after burning Increase CO 2 in the atmosphere: greenhouse effect
Composition of the Atmosphere Trace Gases: Other gases are present in very small amounts Water Vapor: Water in the form of gas Always present in various amounts
Importance of Atmosphere Earth s Atmosphere makes conditions right for life on Earth. Atmosphere has oxygen and other gases we need
Importance of Atmosphere Atmosphere keeps temp. stable and keeps liquid H 2 O on earth It keeps meteoroids from hitting earth
Air Pressure Since Air has MASS it also has PRESSURE and DENSITY
Properties of Air Air Pressure: the weight of a column of air pressing or pushing down on an area Molecules in air push in all directions
Properties of Air Density: The more molecules in the air, the more dense it is More Dense has more air pressure
Tools for Measuring Air Pressure Mercury Barometer Uses Mercury Standard 76 mm mercury
Tools for Measuring Air Aneroid Barometer Pressure Airtight metal chamber that senses change in air pressure
Tools for Measuring Air Pressure Units of Air Pressure Inches of Mercury Millibars
The Effects of Altitude Air Pressure (INVERSE RELATIONSHIP) Increases as altitude decreases Decreases as altitude increases
The Effects of Altitude Altitude (elevation): Distance above sea level
Effects of Altitude Density (INVERSE RELATIONSHIP) Increases as altitude decreases Decreases as altitude increases
Layers of the Atmosphere 4 Layers of the Atmosphere Troposphere Stratosphere Mesosphere Thermosphere
Layers of the Atmosphere They are classified by temperature
Layers of the Atmosphere Troposphere Tropo- turning or changing Lowest layer of Atmosphere Weather occurs here
Troposphere Temperature decreases as altitude increases Temperature stops decreasing at the top of the troposphere Weather forms thin feathery clouds of ice.
Layers of the Atmosphere Stratosphere Strato- spread out or layer 2 nd layer of the atmosphere
Stratosphere Lower Layer cold -60 o C Middle layer Ozone Absorbs energy from the sun into heat Upper layer warmer Planes fly here
Layers of the Atmosphere Mesosphere Meso- middle layer
Mesosphere Protects the earth from meteoroids Temperature drops
Layers of the Atmosphere Thermosphere Thermo- heat layer and outer most layer Very thin air 0.001 % as dense as sea level air
Thermosphere No definite outer limit Sunlight strikes this layer first Up to 1,800 o C Nitrogen and Oxygen convert this energy into heat
Layers of the Atmosphere Divided into 2 layers Ionosphere Has electrically charged particles called ions
Ionosphere Auroras occur here (in the Ionosphere) Caused by particles from the sun that enter the ionosphere near the poles Glow Aurora Borealis (Northern Lights) Aurora Australis (Southern Lights)
Layers of the Atmosphere Exosphere Exo- outer Edge of atmosphere before space
Air Quality Air that contains harmful particles and gases is polluted Pollutants: harmful substances in air, water, or soil
Sources of Pollution Natural Sources Forest fires Soil Erosion Dust storms Mold and pollen
Sources of Pollution Human activity farming and construction burning fossil fuels Cars and motor vehicles Factories and power plants
Effects of Pollution Smog Smoke and fog
Effects of Pollution Acid Rain: air that contains more acid than normal damages surfaces of buildings and statues harms lakes and ponds
Improving Air Quality Environment Protection Agency (EPA) Monitors air pollution in U.S.A. Air quality has improved over last 30 years