Discussion 2/7 Review
S. Benish
Spring 2016
Outline
 I. Atmospheric Composition
 II. Energy Transfer
I. Atmospheric Composition
 What are the major constituents of the air you’re breathing?
 78% Nitrogen (N), 21% Oxygen (O2), 1% Argon (Ar) +other gases
 What else is in the air? What are their sources?
 Carbon dioxide (CO2)
 Volcanoes, plant/animal decay, plant respiration, burning of fossil fuels,
deforestation
 Methane (CH4)
 Wetlands, termites, rice paddies, ruminants, biomass burning, landfills,
coal mining, gas production
 Aerosols
 Oceans, erosion, fires, volcanoes, human activity
 Ozone (O3)
II. Energy Transfer
Key term: Latent heat
What is it?
The heat required to melt or evaporate a substance
Examples?
- Ice in a cooler absorbs heat from the drinks
- Body sweat
https://www.youtube.com/watch?v=CAwxhAP9mnc&feature=youtu.be
Energy Transfer cont.
 Key term: specific heat
 What is it?
 The amount of heat required to increase the temperature of 1
gram of the substance 1 °C
 What has a higher specific heat? Water or land?
Types of Energy Transfer
 Conduction
 What is it?
 Energy is transferred from molecule to molecule, requires
contact!
 What’s a good conductor?
 Metals
Types of Energy Transfer
cont.
 Convection
 What is it?
 Energy transfer by movement of fluid (air is considered a fluid)
 What are some examples?
 The sun heating the surface (“hot air rises and cool air sinks”)
 Lava lamps
 How are temperature and density related?
 Recall the Ideal Gas Law:
 Density=Pressure/Temperature X constant
 As temperature rises, density falls
 “The less dense air floats”
Types of Energy Transfer
cont.
 Advection
 What is it?
 Horizontal movement of air
 What are some examples?
 Wind
 What will happen to air that is pushed up a mountain?
When it sinks again?
Types of Energy Transfer
cont.
 Radiative Heat/Radiation
 What is it?
 Heating due to electromagnetic radiation
Radiation cont.
 The sun emits only a part of its energy in the IR portion
of the spectrum
 In fact, the energy from the sun peaks in the viibble part
of the spectrum (shorter wavelengths than IR)
 Earth emits almost all of its energy at IR wavelengths
 Solar radiation is often called shortwave radiation
 Earth’s radiation is often called longwave radiation
This image shows how much radiation is absorbed by the atmosphere at different
wavelengths
Key Terms
 Latent heat
 Specific heat
 Conduction
 Convection
 Advection
 Longwave radiation
 Shortwave radiation