Wind Chapter 6 Lesson 2

WHAT IS WIND? Air moves from areas of high pressure to areas of low pressure. This movement of air is the wind A global wind moves steadily over long distances in predictable directions Winds that blow between 30*N and 30*S became known as trade winds The particles in cold air are more dense than the particles in warm air. Cold air sinks and warm air rises

What are local winds? Sea Breeze Land Breeze The sun warms up the land and the sea. The temperature of the land increases faster than the temperature of the water Air over the land becomes warmer than air over the sea. The warm air over the land becomes less dense and the warm air rises The cooler, more dense air over the ocean moves toward the warmer air over the land. If you are visiting the beach, you feel the wind blowing from the ocean to the land= sea breeze As night falls, the land and the water both begin to cool. Land cools faster than water, so the air over the water stays warmer=lower density The air over the water rises, and cooler, higher density/pressure air over the land moves toward the water If you are on the beach in the evening, you may feel the wind blowing from the land toward the ocean

How is wind measured? Winds are described by their direction and speed Wind Sock is another tool that measures wind direction Anemometer measures wind speed using three or four cups that rotate when the wind blows Weather Vane- an instrument that shoes which way the wind is blowing