 Water vapor is the source of all condensation and precipitation  Essentially all water on Earth is conserved –> water cycle

 Changing states requires energy transfer in the form of heat  Water has a high Specific Heat  Which means a large amount of energy is gained or lost as water changes temperature

 The addition of heat:  Melting  Evaporation  Sublimation – solid directly to gas  The removal of heat  Freezing  Condensation  Deposition – gas directly to solid

 Saturation – the maximum quantity of water vapor air can hold at a given temperature and pressure  Warm air can hold more water vapor than cool air

 Ratio of the air’s actual water vapor content compared with the amount of water air can hold at that temperature and pressure  2 ways to change RH  1. Add or remove water vapor  2. Change the temperature  Higher temp: ________________  Lower temp: ________________

 Once air is saturated further cooling causes condensation (ex: dew, clouds)  Condensation nuclei: tiny bits on which water condesates (dust, smoke, salt)

 Measured using a psychrometer

 Dew Point –Temperature to which air would have to be cooled for saturation to occur  Depends on? __________________  For every 10° C increase in temp. the amount of water vapor for saturation double  High dew points indicate moist air  Low dew point indicate dry air

 Dew point can found by using the RH  When air temp. and dew point are close: RH is high  When air temp. and dew point are far apart: Rh is low

 -When air expands: ______________  -When air is compressed: ________

 Orographic : elevated terrains such as mountains act as barriers to air flow  Frontal Wedging: warmer, less dense air rises over colder, denser air  Convergence: when air flows in from multiple directions, lifting results (Ex. Florida)  Convective: unequal heating of earth’s surface creates ‘pockets’ of rising air (parking lots)

 Stable air remains in its position  Unstable air tends to rise  Most stable occurs with a temperature inversion which means air temp increases as you go up in altitude  Stability & Weather:  Stable air: _________________________________  Unstable air: ________________________________

 Classified based on form and height  Cirrus: high, white, thin  Cumulus: rounded with flat base  Stratus: sheets or layers of clouds  Nimbus: rainy clouds  Combinations of these are used to describe any cloud(Cumulonimbus= ____________________)

 Occurs when temp. drops below Dew Point  Warm air moving over cold surface  Cold air moving over warm water

 Cloud droplet less than 20 micrometers across  Must grow a million times larger to rain  Most precipitation starts as SNOW  Sleet: melts then refreezes closer to ground  Freezing rain: is sleet that hasn’t refrozen  Hail: Balls of ice from thunderstorms