Brain Bender  What causes wind?

Winds

Goals  1. Describe what causes winds.  2. Name the four types of local winds. 

Cause of Wind

Wind  Result of differential heating  Not all air masses heat and cool at the same rate  Warm air rises, cool air sinks  Water vapor has less mass than air

Differential Heating

Causes for Local winds  Land heats faster than water  Water holds heat longer  Geography, seasons and time of day affects winds

Local Winds  Named for the direction from which they come.  Sea Breezes  Land breezes  Mountain Breezes  Valley Breezes

Global winds  Equator gets most solar energy  Rising air = lower pressure  Falling air = high pressure  Moist air is less dense than dry air  Rising-sinking air is deflected by Earth turning (Coriolis effect)

Sea Breezes

Sea Breezes ~ factors  Occurs during the day  Air above the land heats faster and becomes less dense.  Cool air from water moves in to replace warm air.  This creates the breeze.

Sea Breezes

Land Breezes

Land Breezes ~ factors  Usually occurs at night.  Cooler air over land flows towards warmer water.  This pushes the warm air up.

Land Breezes

Valley Breezes

Valley Breezes ~ factors  Occurs during the day  Air heats in the valleys and rises.  Air flows along the valleys and up the mountains.

Valley Breezes

Mountain Breezes

Mountain Breezes ~ factors  Occur at night  Air cools in mountains and sinks to valleys.

Mountain Breezes

Goals  1. Describe what causes winds.  2. Name the four types of local winds. 