Energy in Atmosphere

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Energy in Atmosphere
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Part 1. Atmosphere Formation

• Ancient volcanic eruptions released gases into
  atmosphere
• Ammonia, Nitrogen, CO2, CO, Sulfur, Methane,
  Hydrogen
• Water was formed (meteorites released water when
  collide w/ Earth)
• Algae formed in oceans
• Photosynthesis uses CO2 to make O2
• O2 diffuses into atmosphere
• Ozone layer is formed (O3)

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Part 2 Air Pressure

• Force exerted by the weight of air
• Measured with a barometer
• Air Pressure at sea level
• 1 atmosphere
• 15 lbs per sq. inch
• 30 inches of mercury
• 760 mm of mercury
• 1013 millibars (mb)

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Part 2 Air Pressure

1. As altitude increases, air pressure decreases
2. As temperature increases, air pressure decreases

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Part 3 Composition of Atm

• Nitrogen 78
• Oxygen 21
• Argon .4
• Greenhouse Gases absorb Infrared (warming)
  radiation
• CO2
• Water Vapor
• Chlorofluorocarbons (CFCs)
• Methane
• Ozone filters out UV (skin cancer) radiation

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Part 4 Energy

• Energy is transferred from warmer to cooler
  substances
• Heat Source warmer
• Heat Sink cooler
• Temperature
• Average Kinetic Energy of the particles in a
  substance
• Higher Temp faster moving particles

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Part 5 Heat Transfer Methods

• Conduction
• Contact between hot substance and cooler
  substance (touching)
• Curling Iron
• Convection
• Heated material rises b/c it has a lower density
• Happens in liquids and gases

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Water loses heat to air becoming cooler and more
dense
Heated water rises
Cooler water sinks
Water is heated, becomes less dense
Convection Cell one cycle Convection Current
2 or more cycles
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Part 5 Heat Transfer Methods

• Radiation
• Energy transfer by waves of energy
• Suns energy to Earth
• Example
• Light Bulb
• Microwave

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Part 6 Electromagnetic Radiation

1. Vibrating particles have electrical charges that
   also vibrate forming electromagnetic waves

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Part 6 Electromagnetic Radiation

• Frequency
• Number of crests passing a point in one second
• Hertz (Hz) is unit for frequency
• As wavelength gets longer, freq gets smaller

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Electromagnetic Radiation
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Part 7 Electromagnetic Spectrum

1. Each form of energy has a specific frequency and
   wavelength
2. ALL forms travel at speed of light 186,000
   miles/sec or 3x108 m/s
3. Visible Light maximum intensity
4. When waves are absorbed and then re-radiated
   (given off), they have longer wavelengths

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Part 8. Heating of Land and Water

• Land absorbs heat energy FASTER and cools FASTER
  than water
• Reasons for Results
• Land is darker and rougher, so it is a better
  absorber and radiator of energy
• Water has a higher specific heat so it heats and
  cools more slowly

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Heating of Land and Water

• Effects on Earth due to different heating rates
  of land and water
• Climate
• Cooler summers near water
• Warmer winters near water
• Water causes areas near water to have small
  seasonal changes and temperature ranges

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Heating of Land and Water

• Air above surface
• Air is mainly heated by energy re-radiated from
  surface (terrestrial radiation) infrared
  radiation longer wavelengths
• Since land gives off energy faster, air over land
  heats and cools faster than air over water

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Part 9. World-Wide Air Circulation

• Coriolis Effect
• Apparent bending of wind b/c of the rotation of
  the Earth
• Northern Hemisphere wind curves to RIGHT
• Southern Hemisphere wind curves to LEFT
• Coriolis effect influences wind direction.

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Part 10. Insolation

• Greenhouse Effect
• Process to heat the atmosphere
• Earth absorbs radiation from Sun
• Energy is re-radiated to the atmosphere with a
  longer wavelength (infrared)
• Infrared radiation gets absorbed by gases (CO2
  and water vapor) and remains trapped in atmosphere

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Part 11. Insolation Temperature Lag

1. Suns energy is first absorbed by Earths
   surface, then given off as infrared radiation
   which warms the air
2. There is a time difference (lag time) between
   greatest intensity of insolation and the time of
   highest temp
3. Also true for lowest intensity and temp

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Part 12. Measuring Temp and Heat

• Temperature
• Measures the average Kinetic Energy of molecules
• Water
• Celsius 100 º boils, 0 º freezes
• Fahrenheit 212 º boils, 32 º freezes
• Kelvin 373 º boils, 273 º freezes, 0 º absolute
  zero
• Absolute Zero
• Coldest possible temp, molecules stop moving, no
  KE
• -273 º C, -459 º F or 0 º K

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Part 12. Measuring Temp and Heat

• Heat
• Measures the TOTAL amount of ALL Kinetic Energy
  in all molecules of substance
• Measured in joules

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Part 12. Measuring Temp and Heat

• Specific Heat
• Amount of heat needed to raise one gram of a
  substance 1 º C
• Specific Heat of Water 4.18 joules/gºC
• Lower the specific heat, the faster something
  will heat up or cool off.

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Part 13. States of Matter

• Solids
• Particles close together, definite shape
• Liquids
• Particles more separated, assumes shape of
  container
• Gases
• Particles farther apart than liquids

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Part 14. Changes of State

• Melting
• Solid to liquid
• Needs heat energy that is stored as Potential
  Energy (no temp change)
• Heat of Fusion heat needed to change 1 gram of
  solid into liquid
• HF for water 334 Joules/g

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Part 14. Changes of State

• Freezing (Fusion)
• Liquid to solid
• Heat is removed (given-off)
• Use Heat of Fusion also

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Part 14. Changes of State

• Vaporization (evaporation)
• Liquid to gas
• Needs heat energy that is stored as Potential
  Energy (no temp change)
• Heat of Vaporization heat needed to change 1
  gram of liquid into gas
• HV for water 2260 Joules/g

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Part 14. Changes of State

• Condensation
• Gas to liquid
• Heat is removed (given-off)
• Use Heat of Vaporization also

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Part 14. Changes of State

• Problems
• 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

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Part 14. Changes of State

• 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

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Part 14. Changes of State

• 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?

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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 ?