wind ch.2 sec. 3. what is wind? the horizontal movement of air caused by differences in air pressure...
TRANSCRIPT
Wind
Ch.2 Sec. 3
What is wind?
• The horizontal movement of air
• Caused by differences in air pressure
• Air moves from high to low
• These differences in air pressure result from uneven heating–Hot air = less dense = lower
pressure
–Cold air = more dense = higher pressure
• If a cooler area is next to a warmer area the air will flow from cool to warm
• Cooler air tends to be lower down so it flows under warmer air–Warmer air gets pushed up
Measuring wind• Two properties
–Direction
–Speed
Wind direction• Measured with a wind vane• Vane points to where wind is
coming from• This direction give wind its
name–Ex. A north wind blows from the
north to the south
Wind speed
• Measured with an anemometer–Wind causes it to spin
–Speedometer measures speed of spinning
Effect of wind
• Can affect how warm/cold it feels outside
• Wind-chill factor–Increased cooling due to wind
–The stronger the wind the colder it feels
Types of Winds
• Local winds
• Monsoons
• Global winds
• Jet streams
Local winds
• Blow over short distances
• Caused by unequal heating within a small area
• Only happen if no wind from farther away
• Often felt near bodies of water
• Water heats and cools more slowly than land
• During the day land is warmer than water wind from water–Sea breeze
• At night the water is warmer than land wind towards water–Land Breeze