Water in the Water in the AtmosphereAtmosphere

What do you observe from What do you observe from the glass/water/ice demo. the glass/water/ice demo. Why do you see this? Why do you see this?

Explanation:Explanation:

water in the atmosphere video water in the atmosphere video

Water Cycle -Water Cycle -The continuous The continuous movement of water between the movement of water between the atmosphere and Earth’satmosphere and Earth’s surface.surface.

takes about 9 days

HumidityHumidity• A measure of the amount of A measure of the amount of

water vapor in the air.water vapor in the air.

• Warm air can hold more water Warm air can hold more water vapor than cool air.vapor than cool air.

Relative HumidityRelative Humidity

• The percentage of water vapor The percentage of water vapor that is in the air compared to the that is in the air compared to the maximum amount of water vapor maximum amount of water vapor the air can hold.the air can hold.

• Depends on temperatureDepends on temperature

• Higher % results in precipitationHigher % results in precipitation

• Demo or relative humidity demoDemo or relative humidity demo

PsychrometerPsychrometer

• Used to measure relative Used to measure relative humidityhumidity

• Has a wet-bulb thermometer and Has a wet-bulb thermometer and a dry-bulb thermometer.a dry-bulb thermometer.

• The wet-bulb thermometer is The wet-bulb thermometer is cooled by evaporation, so the cooled by evaporation, so the reading drops below that of the reading drops below that of the dry-bulb thermometer.dry-bulb thermometer.

• Analyze data on p.302Analyze data on p.302

How Does Fog/ Cloud How Does Fog/ Cloud Form?Form?• Condensation: molecules of water Condensation: molecules of water

vapor in the air become liquid vapor in the air become liquid water (remember the FQ video)water (remember the FQ video)

• Two conditions are required for Two conditions are required for condensation: condensation: cooling of the air cooling of the air below dew pointbelow dew point and the and the presence presence of particlesof particles in the air. in the air.

• hot water fog and fog in a bottlehot water fog and fog in a bottle

Dew PointDew Point

• The temperature at which The temperature at which condensation begins.condensation begins.

• saturation pointsaturation point

• tomorrow’s labtomorrow’s lab

Types of CloudsTypes of Clouds

Classified by:Classified by:

• shapeshape

• altitudealtitude

• precipitationprecipitation

NASA cloud videoNASA cloud video

Types of CloudsTypes of Clouds

• Cirrus ( means a curl of hair)Cirrus ( means a curl of hair)

• Cumulus ( means heap or mass)Cumulus ( means heap or mass)

• Stratus ( spread out, wispy)Stratus ( spread out, wispy)

PrefixPrefix

• Nimbus-/Nimbo- means the cloud Nimbus-/Nimbo- means the cloud produces rain or snowproduces rain or snow

ex: Nimbostratus, Cumulonimbusex: Nimbostratus, Cumulonimbus

• Alto- means medium-altitude cloudAlto- means medium-altitude cloudex: Altostratus, altocumulusex: Altostratus, altocumulus

• Cirro- means high-altitude cloudCirro- means high-altitude cloudex: Cirrocumulusex: Cirrocumulus