1. Wind
Unit 7

2. Wind and Air Pressure Air never stops moving.
The constant circulation of air depends on temperature and air pressure.
That is what makes wind.
Wind carries heat and moistures around the world.
Atmospheric pressure and the temperature make wind.
Wind moves depending on the pressure.

3. Wind and Air Pressure, cont.
Air moves from areas of high pressure to areas of low pressure.
Air depends on many different things.
Cold air is heavier and creates high pressure. These are called highs.
This sinking air absorbs moisture in the air and clear skies with no precipitation.
Warm air is light and rises into the atmosphere creates areas of low pressure or depressions.

4. Prevailing Winds
Some winds blow all the time in the same place. They are called prevailing winds.
They are generated because the direct rays of the Sun heat the air at the equator more than the air at Earth’s North and South poles.
Hot air then moves north and south from the equator. Cooler air moves in to take the place of the warm air.

5. The Coriolis Effect
The rotation of Earth spinning on its axis changes the direction of the wind.
Earth spins from the west to east.
This rotation of Earth deflects winds to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

6. Wind Speed
The speed of wind depends upon differences in air temperature.
The force of wind is measured on the Beaufort Wind Scale. It goes from 0 to 12- from no wind to hurricane-force winds.
It describes the effect of wind on the objects it encounters on the ground.
Wind speed is measured by an anemometer.

7. Wind Power Man has learned to harness the wind thousands of years ago.
Wind generators are used in many countries, including the United States, to generate electricity.

8. Facts to Remember Wind is the movement of air.
Local winds can be created by the movement of warm and cool air from land to sea.