Cloud Formation Clouds and Cloud Formation Mr. Fetch’s Earth Science Classroom
What is a cloud? Clouds: groups of tiny water drops. CLOUDS FORM WHEN: Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom
Air cools when it expands Air Air Air Air Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom
Cooling air causes it to Condense The temperature when condensation begins is called the Dewpoint Temperature. Air cools by expanding. Cooling air increases Relative Humidity. Air becomes full of water } SATURATED Water condenses out of the air. GAS LIQUID Clusters of water drops are called clouds. Dust and salt in the atmosphere are examples of condensation nuclei Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom
Summary: Cloud Formation AIR CONDENSES AIR COOLS AIR RISES By convection By expanding Cools to the dewpoint and water vapor condenses. Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom
Dew Point • Dew point is the temperature to which air must be cooled to reach saturation • Saturation is the point at which the air holds as much water vapor as it possible can • Condensation-Occurs when matter changes from a gas to a liquid
What is a Cloud? • A collection of water droplets • Why White? -They are white, because they reflect the color of the sun. • Why Gray? – They are gray when the sun is unable to shine through.
Cloud Formation • Clouds form when warm moist air rises, expands and then cools • Condensation nuclei are small particles in the atmosphere around which cloud droplets can form • When millions of these droplets collect a cloud forms
Cloud Formation • When a mass of rising air reaches its lifted condensation level (LCL) water vapor condenses into droplets of liquid water or ice • If the density is great enough they become visible in the form of a cloud
Cloud Formation • Clouds are classified by the altitude at which they form: • Low Clouds-Form below 2000 meters • Middle Clouds-Between 2000-6000 meters • High clouds-Form above 6000 meters
Groups of clouds • There are three groups of clouds. • High Clouds - Cirrus • Medium Clouds - Alto • Low Clouds - Cumulus • Clouds that grow vertical • Stratus • Special Clouds • Fog is a special cloud.
Cloud Classification • Clouds are classified based on their height: • Strato-Refers to Low Clouds(Below 2000 meters) • Alto-Refers to middle clouds(2000-6000 meters) • Cirro-Refers to high clouds(Above 6000 meters)
Cloud Classification • Shape: • Nimbus-Describes low, gray rain clouds • Stratus-Describes Featureless sheets of clouds
Cloud Classification • Cumulus-Describes Puffy, lumpy looking clouds • Cirrus-Describes wispy, stringy clouds
Types of High-level Clouds • There are three types of high-level clouds: • Cirrus • Cirrostratus • Cirrocumulus
Cirrus • Cirrus clouds are above 18,000 feet. • They are long and wispy. • Usually mean good weather. • What does a cirrus cloud look like?
Cirrostratus • Thin and sheet like. • Brings bad weather.
Cirrocumulus • Rows of long white puffs. • Look like fish scales. • In tropical regions.
Types of medium-level Clouds • There are two types of medium-level clouds: • Altostratus • Altocumulus • Medium-level clouds are between 6,500 – 18,000 feet in the air.
Altostratus • Are colored gray or blue-gray. • Covers the whole sky. • Appear before long periods of rain or snow.
Altocumulus • Are puffy and gray. • Usually bring thunderstorms.
Types of low-level clouds • There are three types of low-level clouds: • Stratus • Stratocumulus • Nimbostratus • Low-level clouds only go up to 6,500 feet in the air.
Stratus Clouds • Stratus clouds cover the whole sky. • Looks like fog in the sky. • Brings light rain. • What does a stratus cloud look like?
Stratocumulus • Are low, puffy, and gray. • Form in rows. • Can turn into a Nimbostratus cloud.
Nimbostratus • Are dark gray. • Associated with rain and/or snow. • Produce precipitation light to moderate.
Clouds that grow vertical • There are two types of clouds that grow vertical: • Cumulus • Cumulonimbus • Vertical means: (in this case) to grow upward.
Cumulus Clouds • Cumulus clouds are big, white, and puffy. • They grow upward. • What does a cumulus cloud look like?
Cumulonimbus • Are anvil shaped. Winds blow the top of the cloud to make it flat. • Associated with severe weather. • The tip of the cloud points in the direction it is moving.
How is fog formed? • Fog is a cloud that is on the ground. • Fog is a result of warm air meeting cold air.
Warm up Wednesday November 2nd • 1. what is the device we use for measuring Air pressure? • 2. What are 2 characteristics that are used to define an air mass • 3. What type of air mass forms over a warm moist region • 4. Cold fronts often cause what kind of storms?
WARM UPThursday November 3rd • Atmosphere Vocabulary Quiz Today!!!