Ch 16 Weather

Mrs. HarshSection 1

Weather

• The condition of the atmosphere at a certain time and place.– The condition of the atmosphere is affected by

the amount of water in the air.

Water Cycle

• Water in liquid, solid, and gaseous states is constantly being recycled through the water cycle.

• Water cycle is the continuous movement of water from sources on the earth’s surface.

Humidity

• As water evaporates, it becomes water vapor or moisture in the air.

• The amount of water vapor in the air is called Humidity.

• The air’s ability to hold water changes as the temperature changes.

• As temp , the air’s ability to hold water vapor also .

Condensation

• The process by which a gas, such as water vapor, becomes a liquid.

• Condensation cannot occur until the air is saturated which means it is holding the maximum amount of water at a specific temperature.

• Occurs when saturated air cools.

Clouds:

• A collection of millions of tiny water droplets or ice crystals.

• Form as warm air rises and cools.• When the air cools, it becomes saturated. – Water vapor changes to a liquid or a solid,

depending on air temp.• Below freezing, water vapor changes to ice crystals.

Cumulus Clouds

• Puffy white clouds that tend to have flat bottoms.

• Form when warm air rises.• Generally indicate fair weather.– When these clouds get larger, they produce

thuder storms (cumulonimbus clouds).

Cirrus Clouds

• Thin, feathery white clouds found at high altitudes.

• Form when the wind is strong• If they get thicker, they indicate that a change

in the weather is coming.

Clouds and Altitude• Clouds are also classified by the altitude at

which they form.

Precipitation

Precipitation