Energy in Atmosphere

Part 1. Atmosphere Formation

A. Ancient volcanic eruptions released gases into atmosphere

B. Ammonia, Nitrogen, CO2, CO, Sulfur, Methane, Hydrogen

C. Water was formed (meteorites released water when collide w/ Earth)

D. Algae formed in oceans1. Photosynthesis uses CO2 to make O2

2. O2 diffuses into atmosphere

3. Ozone layer is formed (O3)

Part 2: Air Pressure

A. Force exerted by the weight of air1. Measured with a barometer

2. Air Pressure at sea level:a. 1 atmosphere

b. 15 lbs per sq. inch

c. 30 inches of mercury

d. 760 mm of mercury

e. 1013 millibars (mb)

Part 2: Air Pressure3. As altitude increases, air pressure

decreases

4. As temperature increases, air pressure decreases

Altitude

Altitude

Air

Pre

ssur

e

Temperature

Air

Pre

ssur

e

Temperature

Part 3: Composition of Atm

A. Nitrogen = 78%B. Oxygen = 21%C. Argon = .4%D. Greenhouse Gases – absorb Infrared

(warming) radiation1. CO2

2. Water Vapor3. Chlorofluorocarbons (CFCs)4. Methane

E. Ozone – filters out UV (skin cancer) radiation

Part 4: Energy

A. Energy is transferred from warmer to cooler substances

1. Heat Source = warmer

2. Heat Sink = cooler

B. Temperature1. Average Kinetic Energy of the

particles in a substance

2. Higher Temp = faster moving particles

Part 5: Heat Transfer Methods

A. Conduction1. Contact between hot substance and

cooler substance (touching)

2. Curling Iron

B. Convection1. Heated material rises b/c it has a lower

density

2. Happens in liquids and gases

Heated water rises

Water is heated, becomes less dense

Water loses heat to air becoming cooler and more dense

Cooler water sinks

Convection Cell – one cycle

Convection Current – 2 or more cycles

Part 5: Heat Transfer Methods

C. Radiation1. Energy transfer by waves of energy

2. Sun’s energy to Earth

3. Examplea. Light Bulb

b. Microwave

Part 6: Electromagnetic RadiationA. Vibrating particles have electrical

charges that also vibrate forming electromagnetic waves

CREST

TROUGHWAVELENGTH

Part 6: Electromagnetic RadiationB. Frequency

1. Number of crests passing a point in one second

2. Hertz (Hz) is unit for frequency

3. As wavelength gets longer, freq gets smaller

Wavelength

Fre

quen

cy

Electromagnetic Radiation

Part 7: Electromagnetic SpectrumA. Each form of energy has a specific

frequency and wavelength

B. ALL forms travel at speed of light: 186,000 miles/sec or 3x108 m/s

C. Visible Light – maximum intensity

D. When waves are absorbed and then re-radiated (given off), they have longer wavelengths

Part 8. Heating of Land and Water

A. Land absorbs heat energy FASTER and cools FASTER than water

B. Reasons for Results1. Land is darker and rougher, so it is a

better absorber and radiator of energy

2. Water has a higher specific heat so it heats and cools more slowly

Heating of Land and Water

C. Effects on Earth due to different heating rates of land and water

1. Climatea. Cooler summers near water

b. Warmer winters near water

c. Water causes areas near water to have small seasonal changes and temperature ranges

Heating of Land and Water

D. Air above surface1. Air is mainly heated by energy re-

radiated from surface (terrestrial radiation) = infrared radiation = longer wavelengths

2. Since land gives off energy faster, air over land heats and cools faster than air over water

Part 9. World-Wide Air Circulation

A. Coriolis Effect1. Apparent bending of wind b/c of the

rotation of the Earth

2. Northern Hemisphere – wind curves to RIGHT

3. Southern Hemisphere – wind curves to LEFT

4. Coriolis effect influences wind direction.

Part 10. Insolation

A. Greenhouse Effect1. Process to heat the atmosphere

2. Earth absorbs radiation from Sun

3. Energy is re-radiated to the atmosphere with a longer wavelength (infrared)

4. Infrared radiation gets absorbed by gases (CO2 and water vapor) and remains trapped in atmosphere

Part 11. Insolation – Temperature Lag

A. Sun’s energy is first absorbed by Earth’s surface, then given off as infrared radiation which warms the air

B. There is a time difference (lag time) between greatest intensity of insolation and the time of highest temp

C. Also true for lowest intensity and temp

Part 12. Measuring Temp and Heat

A. Temperature1. Measures the average Kinetic Energy of

moleculesa. Water

1. Celsius: 100 º boils, 0 º freezes

2. Fahrenheit: 212 º boils, 32 º freezes

3. Kelvin: 373 º boils, 273 º freezes, 0 º absolute zero

a. Absolute Zero1) Coldest possible temp, molecules stop

moving, no KE

2) -273 º C, -459 º F or 0 º K

Part 12. Measuring Temp and Heat

B. Heat1. Measures the TOTAL amount of ALL

Kinetic Energy in all molecules of substance

2. Measured in joules

Part 12. Measuring Temp and Heat

C. Specific Heat1. Amount of heat needed to raise one

gram of a substance 1 º C

2. Specific Heat of Water = 4.18 joules/gºC

3. Lower the specific heat, the faster something will heat up or cool off.

Part 13. States of Matter

A. Solids1. Particles close together, definite shape

B. Liquids1. Particles more separated, assumes

shape of container

C. Gases1. Particles farther apart than liquids

Part 14. Changes of State

A. Melting1. Solid to liquid

2. Needs heat energy that is stored as Potential Energy (no temp change)

3. Heat of Fusion – heat needed to change 1 gram of solid into liquida. HF for water = 334 Joules/g

Part 14. Changes of State

B. Freezing (Fusion)1. Liquid to solid

2. Heat is removed (given-off)

3. Use Heat of Fusion also

Part 14. Changes of State

C. Vaporization (evaporation)1. Liquid to gas

2. Needs heat energy that is stored as Potential Energy (no temp change)

3. Heat of Vaporization – heat needed to change 1 gram of liquid into gasa. HV for water = 2260 Joules/g

Part 14. Changes of State

D. Condensation1. Gas to liquid

2. Heat is removed (given-off)

3. Use Heat of Vaporization also

Part 14. Changes of State

E. Problems1. How much heat is needed to change 20g

of ice at 0 º C into 20g of water at 0 º C?Heat Energy (Q) = Mass (m) x HF

Q = mHF

Q = 20g x 334 J/g

Q = 6680 Joules

Part 14. Changes of State

2. How much heat must be lost to turn 50 g of water at 0 º C into ice at 0 º C ?Q = mHF

Q = 50g x 334 J/g

Q = 16700 Joules

Part 14. Changes of State

3. How much energy is needed to turn 50g of water at 100 º C into 50g of steam at 100 º C ?Q = mHV

Q = 50g x 2260 J/g

Q = 113,000 Joules

Which takes more energy melting ice or boiling water?

1) What temp does this substance melt?2) What temp does it boil?3) At this rate, how long does it take to turn the

substance from a solid at 40 º C into gas at 170 º C ?