Air Pressure and Wind
Main Idea: Differences in air pressure on Earth’s surface cause wind.
 How Can Air Pressure Change?
1. Volume
2. Height Above Earth’s Surface
3. Temperature
4. Amount of Water Vapor
 Wind- Air that moves horizontally ( left and right)
 Updraft- air that rises
 Downdraft- air that sinks
 Convection Cells
o Warmer air is less dense
o Cooler air is more dense
o Warm air rises above the denser cool air.
o Denser, cool air sinks.
o The unequal heating and cooling together causes a circular pattern.
o Part of the atmosphere
 Convection Cell- a circular pattern of air rising, air sinking and wind.
o Happen by the water and by mountains.
o Cause valley breezes and mountain breezes
 What are Sea and Land Breezes?
 Sea breeze- a wind that blows from the sea towards the land.
 Land breeze- a wind that blows from the land towards water
 What is the Coriolis Effect?
o Coriolis effect- The curving of the path of a moving object caused
by Earth’s rotation.

In the Northern Hemisphere wind blows to the right.

In the Southern Hemisphere winds blow to the left.
 What are Isobars?
Isobar- a line on a map connecting places with equal air pressure.
o Help predict how fast air will move.