1. Relative humidity and dew point (elt 2, 3, 4)

2. Layers of atmosphere Thermosphere: Temps increase w/height
No well-defined upper limit
Mesosphere:
Temps decrease w/ height
Meteors
Stratosphere:
Ozone layer
Troposphere:
Temps decrease w/height
Weather occurs

3. Relative humidity 
the amount of water vapor in the air compared to what the air can "hold" at that temperature represented as %
Warm air holds more vapor, cold air holds less vapor
100% = saturation, 100%+ vapor condenses into liquid (clouds, fog, dew)

4. Dew point
Represented as temp (°F/C)
The temperature at which air reaches 100% humidity (saturation)
Higher the dew point, the more moisture in the air (the more “sticky” if feels)

5. Cloud formation
The sun heats up the air (and water vapor in the air)radiation
This causes air to rise (low pressure) convection
Relative humidity over 100% (dew point reached)
Water vapor is cooled to dew point during upward movement
Vapor condenses into droplet on dust particles in atmosphere