Chapter 21

Front

Air pressure

Back

The force exerted by the weight of air molecules.

Front

Wind

Back

The horizontal movement of air from high to low pressure.

Front

Jet stream

Back

A fast moving air current in the upper atmosphere that determines the movement of weather systems.

Front

High-pressure system

Back

A region of sinking air, spinning clockwise and outward that usually causes fair/clear skies and dry weather.

Front

Low-pressure system

Back

A region of rising air, spinning counterclockwise and inward which often causes clouds and precipitation. Fronts extend outward from areas of low pressure.

Front

Sea breeze

Back

Air coming from the water due to rising motions (low pressure) over the land that is heated during the day.

Front

Land breeze

Back

Air coming from the land due to sinking motions (high pressure) over the land that is cooled during the night.

Front

Wind speed

Back

Determined by the pressure gradient (change in pressure ÷ distance). Large pressure gradients create windy weather.

Front

Temperature and moisture's influence on air pressure

Back

Warm and moist air has a lower density leading to low pressure, cold and dry air leads to high pressure due to a higher density.