WATER in the Atmosphere

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WATER in the Atmosphere
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Needs Heat
Lose Heat
Vaporization Evaporation
Condensation Precipitation
DEPOSITION
Liquid
SUBLIMATION
Melting
Freezing
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Water Cycle
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• EVAPORATION Liquid to Gas
• CONDENSATION Gas to Liquid

Clouds condensed water vapor
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Dew Point The temperature when water will
condense in the air or ground. Frost frozen
dew
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How are Clouds formed? Dew Point Air
TemperatureClouds In order for clouds to form
the water must condense on a particle like dust
or smoke.
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RISING AIR
Air cools as it rises. As air cools to the dew
point, it condenses to form clouds.
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RISING AIR

• Rising air can be caused by
• Low Pressure Air
• Air Fronts
• Lifting of air over elevated topography such as
  mountains

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Convection CurrentWarm, rising air cooler air
clouds

• Wind hits the side of the mountain
• Air is forced to rise
• Air cools at is rises
• Lots of moisture on one side, dry on the other

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Ingredients for Precipitation
1. Moisture in the Air
2. Rising Air
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PRECIPITATION
Rain drops of water (most common) Sleet
Frozen rain Freezing Rain starts as snow, melts
refreezes the instant it hits the ground. Hail
round pellets of ice Snow water vapor as ice
crystals
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• Humidity
• It is the measure of the amount of water vapor in
  the air
• Relative Humidity
• The percentage of water vapor in the air compared
  to the maximum amount of water that the air can
  hold.

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How do we measure Relative Humidity?

• Psychrometer
• measures relative humidity.
• It is also referred to as a wet- and dry-bulb
  thermometer.

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Relative Humidity in Action!!!
Warmer air can hold more water vapor.As air
cools, it can hold less water, it condenses.
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Its not heat, its the humidity

• On a hot day you can still feel comfortable if
  the air is dry. Like in Arizona or a desert it
  is hot, but dry heat.
• Evaporation of sweat helps to cool your core body
  temp
• When Relative Humidity is high, the evaporation
  process slows down. And your body can not cool
  down.
• ex When you are in a rainforest (high humidity)
  you can not cool your body down because the air
  around you is saturated with water and your sweat
  will not evaporate into the air.

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• DUE FRIDAY!!
• WRITING PROMPTS (pick one)
• Imagine you are a drop of water in the ocean.
  Write a diary describing your journey through the
  water cycle. How do you become a cloud? What
  conditions cause you to fall as precipitation?
  Use descriptive words to describe your journey.
• Evaluate the method of cloud seeding. Why would
  it work? How economical is it? Is there an
  alternative? How is the water cycle interrupted
  during a drought?