Earths Atmosphere

1. Earths Atmosphere

2. Chapter 1:Earth’s Changing Atmosphere 1.1 Earth’s Atmosphere Supports Life Air – mixture of gases Atmosphere – layer of air that surrounds the Earth 1. Supports life and protects it 2. Keeps Earth warm 3. Transports energy

3. Characteristics of the Atmosphere Altitude – distance above sea level The thickness or thinness of air is measured by its density. Density – the amount of mass in a given volume of a substance *Atmosphere’s density decreases as you travel upward.

4. Gases in the atmosphere: Nitrogen (N2) – 78% Oxygen (O2) – 21% Carbon Dioxide (CO2), argon, other gases – 1% • Nitrogen – promotes plant growth • Oxygen – animals and plants perform life processes • Carbon dioxide – plants use to make food

5. Cycles – processes that are repeated over and over again • 1. Carbon Cycle : a. Oxygen inhaled by animals, exhales Carbon Dioxide (CO2) • b. CO2 taken in by plants, releases Oxygen (O2) • 2. Nitrogen Cycle : • a. tiny organisms (living things) remove N2 from air, changes it into other chemicals and returns it to the soil. • b. plants/animals use solids/liquids that contain N2, then return to soil when they die & decay. • c. soil slowly releases N2 back in the air • 3. Water Cycle: • a. Liquid water from oceans & lakes changes into • gas (evaporates) and enters atmosphere • b. Plants release water vapor from leaves • c. Liquid water falls back to atmosphere as • precipitation – rain, snow, sleet, or hail.

6. Sudden Changes: • **Volcanic eruptions, forest fires, dust storms can cause changes in the atmosphere Volcanic Eruptions – shoots gases and ash into the atmosphere. Forest Fires – when forests burn, carbon that makes up the trees enters the atmosphere as carbon dioxide. Dust Storms – Adds huge amounts of particles to the air.

7. Section 1.2: The Sun Supplies the Atmosphere’s Energy • Two main things happen to sunlight when it hits the Earth: 1. Sunlight is reflected – you see most objects by reflected sunlight 2. Sunlight is absorbed – sand absorbs sunlight & becomes warm

8. The Atmosphere Moves Energy • Processes that move Energy from place to place: • Radiation - Energy that travels distances in waves, can be absorbed or reflected. • Conduction – Transfer of heat energy from one substance to another by direct contact. • Convection – Transfer of energy by the motion of gas or liquid. Movement of gases up and down. Warm air rises, cool air sinks. Example: 1. Radiation from sun warms the sand 2. Hot sand conducts energy to feet, air –or anything that touches the sand 3. Warm air carries energy upward by convection

9. 1.3 - Gases in the Atmosphere pgs. 22-25 • Atmosphere effects light in 4 ways: • Absorb light • Reflect light • Let it pass through • Give off light – emit light

10. 1.3 - Two types of radiation (energy): • 1. Ultraviolet radiation – waves of energy you can’t see, causes sunburn. • 2. infrared radiation – warms the materials that absorb it.

11. 1.3 - Earth’s Protection: • Ozone layer – ozone gases in the stratosphere, protects life on earth by absorbing harmful ultraviolet rays from sun. • Greenhouse effect – traps heat – absorbs gases (carbon dioxide, methane, etc.) and keeps earth warm – allows heat to go back into space. • Keeps Earth’s average surface temp. around 59 degrees.

12. Air Masses 3.1 – pgs. 79-82 • Air Mass – large body of air. covers thousands of miles. • Characteristics of Air Mass: depends on where it forms and the temperature • 1st word tells where it forms (land or water) • 2nd word tells temp. (near or far from equator)

13. Four Types: • Continental Tropical – dry and warm • Continental Polar – dry and cool • Maritime Tropical – moist and warm • Maritime Polar – moist and cool Air Masses move from West to East – away from where they start. Takes on characteristics of earth’s surface as it moves.

14. Front – boundary between air masses. fronts are often cloudy or stormy 3 types: • Cold Front – cold air mass pushes a warm air mass. Produces cumulonimbus clouds. Brief heavy storms. Cool weather • Warm Front – warm air mass pushes cold air mass. Hours of rain or snow – warm air • Stationary Front – Two air masses push against each other and stop moving. Becomes warm or cold when one air mass advances.

15. Storms: 3.2 – 3.3 pgs. 87 – 97Storms – 3.2 • High pressure system – can bring clear skies, calm air, gentle breezes • Low Pressure system – brings stormy weather • Tropical Storm – low pressure system that starts at the equator – winds 40 mph (65k)

16. Hurricanes • Hurricane – low pressure system – winds 74 mph (120k) • Hurricane strike between Aug. thru Oct. – when water gets warm enough – loses strength when reaches land • Eye of Hurricane – center of storm, calm winds

17. Storm Surge – pushes huge mass of ocean water onto coastal area. • Winter storms result of two air masses colliding. • NWS – National Weather Service – alerts people to dangerous weather.

18. Blizzards – Blinding snowstorms, winds 35mph, occur in northern and central U.S. • Ice storms – rain falls onto freezing cold ground. • covers everything with ice

19. Severe Storms – 3.3 • Lightning – spark of electricity • Air around lightning is heated briefly to temp. hotter than the surface of sun • Thunder – sharp wave of heated air that travels away from lightning

20. Thunderstorm – storm with lightning and thunder – get energy from humid air. • Effects of Thunderstorms: • Flash floods, winds, hail, lightning • Tornado – violently rotating column of air – occurs mostly in spring - unpredictable