Clouds

Front

Dew Point Noun

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[doo point]

Back

Dew Point

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The temperature at which air becomes saturated with water vapor, causing it to condense into liquid water or ice.

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Example: As an air parcel rises, it cools. When its temperature drops to the dew point temperature, water vapor condenses, forming a cloud.

Front

Troposphere Noun

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[troh-puh-sfeer]

Back

Troposphere

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The lowest layer of Earth's atmosphere where nearly all weather conditions take place and most clouds form.

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Example: The troposphere is the lowest layer of Earth's atmosphere, extending from the ground up to about 12 km, and is where all weather and clouds form.

Front

Fog Noun

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[fog]

Back

Fog

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A type of stratus cloud that forms on or near the ground when humid air cools below its dew point.

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Example: This diagram shows how fog (a low stratus cloud) forms when warm, moist air blows over a colder surface, causing water vapor to condense.

Front

Condensation Noun

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[kon-den-sey-shuhn]

Back

Condensation

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The process where water vapor changes from a gas to a liquid, often forming around tiny atmospheric particles.

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Example: This diagram shows how water vapor, rising from a body of water, cools and turns into tiny water droplets to form a cloud.

Front

Water Vapor Noun

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[wah-ter vey-per]

Back

Water Vapor

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Water in its gaseous state, which is an invisible but essential component for cloud formation in the atmosphere.

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Example: Heat from the sun causes water to evaporate from a river, turning into invisible water vapor that rises and cools to form clouds.

Front

Ice Crystals Noun

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[ahys kris-tuhls]

Back

Ice Crystals

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Tiny, frozen particles of water that form high-altitude clouds when the dew point is below freezing.

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Example: This diagram shows how hexagonal ice crystals, found in high-altitude clouds, bend incoming sun rays and direct the light towards an observer, creating atmospheric optical phenomena.

Front

Convection Noun

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[kuhn-vek-shuhn]

Back

Convection

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The upward movement of warm, less dense air, which can cause clouds to grow vertically into towering formations.

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Example: The sun heats the ground, causing the air above it to warm up and rise. This rising warm air, a process called convection, cools and condenses to form clouds.

Front

Cirrus Noun

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[sir-uhs]

Back

Cirrus

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High-altitude clouds made of ice crystals that are characterized by their thin, wispy, and feathery appearance.

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Example: This diagram shows that Cirrus clouds are thin, wispy clouds found at high altitudes, distinct from other cloud types at middle and low altitudes.

Front

Stratus Noun

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[strey-tuhs]

Back

Stratus

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Low-level, gray clouds that form in flat, horizontal layers and can cover the entire sky like a blanket.

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Example: This diagram shows multiple cloud types at different altitudes, with Stratus clouds correctly depicted as low-level, layered clouds near the ground.

Front

Cumulus Noun

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[kyoo-myuh-luhs]

Back

Cumulus

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Detached, puffy clouds with flat bases and sharp outlines, often associated with fair weather conditions.

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Example: Cumulus clouds are puffy, cotton-like clouds that can grow vertically, changing from small fair-weather clouds to larger, towering forms.