Is warm air heavier or lighter than cold air? Science Starter #1 Is warm air heavier or lighter than cold air? http://www.youtube.com/watch?v=77Ej_Ayugxk

Wind *Wind is air in motion. It is produced by the uneven heating of the earth’s surface by the sun. Since the earth’s surface is made of various land and water formations, it absorbs the sun’s radiation unevenly.

What causes the wind to blow? Cool air REPLACING warm air. Warm air, which weighs less than cold air, rises letting cool air move in and replaces that warm air. This movement of air is what makes the wind blow. http://www.youtube.com/watch?v=PCa64yXkgUw

What does air pressure have to do with air temperature? Air flows from areas of high pressure into areas of low pressure because air always looks for lower pressure.

The Coriolis Effect The rotation of the earth causes moving air and water to appear to have curved. http://www.classzone.com/books/earth_science/terc/content/visualizations/es1904/es1904page01.cfm http://www.youtube.com/watch?v=mcPs_OdQOYU&feature=related

*Wind on earth has it’s own patterns. Global Wind Patterns *Wind on earth has it’s own patterns. The region of Earth receiving the Sun's direct rays is the equator. Here, air is heated, rises and moves to either the north or south pole. This warm air from the equator begins to cool and sink once it reaches the poles. Most of this cooling, sinking air moves back to the equator to replace the warmer air. This movement of air creates many wind patterns.

Global Winds

Can you draw the wind patterns and name them? 30 60

Surface Winds Why does it take longer to fly from Boston to Seattle then it does from Seattle to Boston?

Jet Streams A jet stream is a fast flowing, river of air found in the atmosphere at around 12 km above the surface of the Earth just under the tropopause. They form where there is a significant difference in temperature. Because of the effect of the Earth's rotation the streams flow west to east, in a wave-like manner.

Polar Jet Stream

Sea Breeze Warm Cold The land radiates heat back into the air which causes the air to rise. This air then moves over the ocean which cools. This cooled air replaces the warm air and the cycle continues.

Land Breeze Warm Cold The ocean radiates heat back into the air which causes the air to rise. This air then moves over the land which cools. This cooled air replaces the warm air and the cycle continues.