All About Clouds

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All About Clouds
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Clouds

• For a cloud to form, there must be water vapor in
  the air.
• humidity- the measure of the amount of water
  vapor in the air.
• relative humidity- the percentage of the amount
  of water vapor in the air compared to the maximum
  amount of water the air can hold. Measured with a
  psychrometer.

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precipitation

• Forms of precipitation
• a) rain- drops of water that are at least .5 mm
  in diameter (mist or drizzle if smaller)
• b) sleet- drops of water that freeze as they fall
  from the sky sleet-ice particles that are less
  than 5mm in diameter
• c) freezing rain- dont freeze as they fall but
  freeze as they touch something cold such as tree
  branches or power lines.

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more forms of precipitation

• d) hail- round pellets of ice larger than 5 mm in
  diameter that form in cumulonimbus clouds sent
  up and down in the cloud, freezing a new layer of
  ice around the hailstone.
• e) snow- water vapor in a cloud is converted
  directly into ice crystals

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What is a cloud?

• A cloud is a large collection of very tiny
  droplets of water or ice crystals.
• The droplets are so small and light that they can
  float in the air.

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Why do clouds look white?

• Clouds reflect sunlight, making them white.
• Clouds reflect all the colors of the rainbow the
  same amount, making them appear a white color.

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Why do some clouds appear gray?

• When the clouds get really thick or really high
  in the sky, all the light cant travel through
  the cloud. This makes the cloud look gray instead
  of white.
• The shadows of other clouds can make some clouds
  appear gray also.

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How are clouds formed?

• Clouds form when
• 1. warm air rises, expands and cools.
• 2. some of the vapor condenses onto tiny pieces
  of dust because cool air cant hold as much water
  as warm air.
• A tiny droplet forms around each dust particle.
• They become a visible cloud when billions of
  these droplets come together.

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Various Cloud Types

• Stratus clouds- low level clouds that are thick
  enough to block the sun
• Cumulus clouds- low to midlevel clouds that are
  puffy and white
• Cirrus clouds- thin, whispy clouds that are high
  in the troposphere
• Nimbus clouds- bring rain dark colored

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Click here to see a video about cloud formation
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• Click to view animation of precipitation over
  mountains
• http//bcs.whfreeman.com/thelifewire/content/chp56
  /5602001.html

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Click here to see a video detailing the various
cloud types!