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What is weather

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The Sun's heat evaporates water into the atmosphere forming ... Cumulus. Clouds. High, thin, white, feathery clouds made of ice crystals. Cirrus. Cloud Height ... – PowerPoint PPT presentation

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Title: What is weather


1
What is weather?
  • Environmental Science

2
Weather
  • Weather is the state of the atmosphere at a
    specific time and place.
  • Weather includes air pressure, wind,
    temperature, and moisture in the air.

Atmosphere 79 Nitrogen 20 Oxygen 1 Other
Gases
3
The Suns Heat (Radiation)
  • The Suns heat evaporates water into the
    atmosphere forming clouds and returning the water
    to Earth as rain or snow the Sun also heats the
    air.

4
Temperature
  • Temperature is a measure of air molecule
    movement.
  • The Suns energy causes air molecules to move
    rapidly temperatures are high and it feels warm.
  • When less of the Suns energy reaches air
    molecules, they move less rapidly and it feels
    cold.

5
Wind
  • Wind is air moving in a specific direction.
  • As the Sun heats air, it expands, becomes less
    dense, rises, and has low atmospheric pressure.
  • Cooler air is denser and sinks, causing high
    atmospheric pressure.

6
Wind
  • Air moves from high pressure areas to low
    pressure areas, causing wind.

7
Humidity
  • Humidity is the amount of water vapor in the air.
  • Warmer air can hold more water vapor, tending to
    make it more humid.
  • Relative humidity is the amount of water vapor in
    the air compared to what it can hold at a
    specific temperature.

8
Relative Humidity
9
Humidity
  • When air cools, it cant hold as much water
    vapor, so the water vapor condenses to a liquid
    or forms ice crystals.
  • Dew point is the temperature at which air is
    saturated and condensation forms.

10
Clouds
  • Clouds form as warm air is forced upward and
    cools. Then the water vapor condenses in tiny
    droplets that remain suspended in the air.

11
Clouds
  • The shape and height of clouds vary with
    temperature, pressure and the water vapor in the
    atmosphere.

12
Clouds
  • Smooth, even sheets or layers at low altitudes.

Stratus
13
Clouds
  • Puffy, white clouds, often with flat bases.

Cumulus
14
Clouds
  • High, thin, white, feathery clouds made of ice
    crystals.

Cirrus
15
Cloud Height
  • Cirro high clouds
  • Alto middle-elevation clouds
  • Strato low clouds

16
Clouds
  • Nimbus clouds are dark and so full of water that
    sunlight cant penetrate them.

17
Precipitation
  • Precipitation is water falling from the clouds.
  • Water droplets in a cloud form when water
    condenses around particles in the air, called
    condensation nuclei.
  • When water droplets in clouds combine and grow
    large enough precipitation falls to Earth.
  • Air temperature determines whether the droplets
    form rain, snow, sleet, or hail.

18
Lab Cloud Formation
  • Procedures
  • Tape the black construction paper onto the back
    of the jar so that it is not possible to see
    through the jar.
  • Fill the jar 1/3 full with warm water. Be sure
    the bag of ice and matches are close by.
  • Light the match and hold it over the jar opening.
    Wait a few seconds and drop the match inside the
    jar and quickly cover the jar opening with the
    bag of ice.
  • Observe what happens in the jar.
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