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