1. Air Pressure

2. Air Pressure: the result of the weight of a column of air pushing down on an object (the amount of air pressing down on an object)

3. Tools and Units Barometer: a device that measures air pressure –Mercury Barometer: consists of a glass tube partially filled with mercury, with its open end resting in a dish of mercury –Aneroid Barometer: has an airtight metal chamber with no water Units are inches or millibars (mb) 1in of mercury=33.87 millibars

4. Importance Do basic weather forcasting Barometric pressure changes when a storm comes The lower the air pressure, the more severe the storm The higher you go, the lower the air pressure

5. Other Info 1000mb is a sunny day 900mb is a severe thunderstorm Air flows from high pressure to low pressure –Causes wind

6. Bibliography http://www.usatoday.com/weather/wbaroc x.htmhttp://www.usatoday.com/weather/wbaroc x.htm http://www.freefoto.com/preview/16-11- 51?ffid=16-11-51http://www.freefoto.com/preview/16-11- 51?ffid=16-11-51 http://kids.earth.nasa.gov/archive/air_pres sure/barometer.htmlhttp://kids.earth.nasa.gov/archive/air_pres sure/barometer.html http://www.wxdude.com/page15.html http://www.rcn27.dial.pipex.com/cloudsrus/ pressure.htmlhttp://www.rcn27.dial.pipex.com/cloudsrus/ pressure.html