Water in the Atmosphere Section 2-4 Pages 61-66

How Does Fog Form? Q. How can you explain your observations? Why is there a difference between what happens with the hot water and with the cold water? A. Fog forms in the bottle when warm moist air rises from the surface of the hot water and condenses as it cools near the ice cube. Q. How can you explain your observations? Why is there a difference between what happens with the hot water and with the cold water? A. Fog forms in the bottle when warm moist air rises from the surface of the hot water and condenses as it cools near the ice cube.

Review of the Water Cycle The water cycle is the movement of water between the atmosphere and the Earth’s surface. When is a water droplet a gas?

Humidity Humidity is a 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 the air could hold is called relative humidity.

Relative Humidity The amount of water vapor that the air can hold depends on its temperature. Warm air can hold more water vapor than cool air.

“It’s not the heat, it’s the humidity.” Even on a hot day you can still feel comfortable if the air is dry. When the relative humidity is high evaporation slows down and you feel less comfortable. How does your body cool itself off? Even on a hot day you can still feel comfortable if the air is dry. When the relative humidity is high evaporation slows down and you feel less comfortable. How does your body cool itself off?

Psychrometer Used to measure relative humidity Has two thermometers, a wet-bulb and a dry-bulb Let’s watch USM’s Athletic Trainers demonstarte how to use a sling psychrometer. Used to measure relative humidity Has two thermometers, a wet-bulb and a dry-bulb Let’s watch USM’s Athletic Trainers demonstarte how to use a sling psychrometer.

How Clouds Form How do you think clouds form? Your response should include words like: water vapor, condensation, dew point.

How Clouds Form

Types of Clouds Meteorologists classify clouds into three main types: cumulus, stratus, and cirrus. Clouds are also classified by their altitude. Each type of cloud is associated with a different type of weather. Meteorologists classify clouds into three main types: cumulus, stratus, and cirrus. Clouds are also classified by their altitude. Each type of cloud is associated with a different type of weather.

cloud name = clues about height and structure Cloud Shape Cumulus = heap or mass Stratus = spread out Cirrus = wispy or feathery, high Prefixes Nimbo = produces rain or snow Alto = medium altitude Cirro = high altitude Cloud Shape Cumulus = heap or mass Stratus = spread out Cirrus = wispy or feathery, high Prefixes Nimbo = produces rain or snow Alto = medium altitude Cirro = high altitude

altocumulus altostratus cirrostratus cirrus cumulus fog nimbostratus stratus

Classifying Low-level clouds are: fog, cumulus, stratus, and nimbostratus. Medium-level clouds are : alto cumulus and altostratus. High-level clouds are: cirrostratus and cirrus. Low-level clouds are: fog, cumulus, stratus, and nimbostratus. Medium-level clouds are : alto cumulus and altostratus. High-level clouds are: cirrostratus and cirrus.

Words Worth Knowing (ISN #18) evaporation humidity relative humidity psychrometer condensation dew point cumulus stratus cirrus