1.  Air Pressure: the amount that air presses or pushes on anything  You usually do not notice air pressure, but you do notice its effects Air Pressure and Wind

2.  As you travel higher above the earth, the air pressure changes  Higher=Less Pressure

3.  Temperature also changes the higher you travel.  The Earth’s surface heats the air.  Farther From Earth = Cooler Temperature Temperature: 34ºF Temperature: 54ºF Temperature: 76ºF

4.  As the air near the surface of the earth becomes warmer, the air particles move farther apart.  The air become lighter and rises  This is when a low-pressure area forms Low Air Pressure

5.  Cole air s heavier than warm air.  It’s air particles are packed closer together and push down harder.  This is when a high-pressure area forms. High Air Pressure

6.  Air moves from a place with high pressure to a place with low pressure.  Air moving is called wind.  When the cooler air from a high-pressure area sinks toward the earth, it causes wind.  That’s why you will feel a cool breeze…even on a warm, summer day. Wind

7.  Barometer Measuring Air Pressure

8.  Wind Vane Measuring Wind Direction

9.  Anemometer Measuring Wind Speed

10.  What causes wind? Let’s Review! Wind is caused by air moving from a high-pressure area to a low-pressure area.

11.  How is air pressure measured? Air pressure is measured by a barometer.

12.  How do scientists measure wind direction? Scientists measure wind direction with a wind vane.

13.  How do scientists measure wind speed? Scientists measure wind speed with an anemometer.