13165_40917_weather6
CU of dial barometer. A narrator explains when it reads high the atmosphere directly above us is more dense and we are in a high pressure area. WS of coastal aerial view of ocean, rocks, and land. When it’s stable, though the weather is not always sunny its fair. CU of dial barometer, when it reads low, the atmosphere is exerting less pressure downward because it is less dense and we are in a low pressure area. MWS of top of trees swaying in the wind amongst darker blue sky. Then the air is unstable and we may experience the violent changes which accompany stormy weather. In addition to the fact that it exerts pressure there are two other characteristics, which help to explain the how and why of weather. MS of man in dark room over sink lighting a match. The first is air absorbs heat and the heated air will rise. LS of man reading a paper outside on a lawn chair. Second characteristic is warm air can hold more moisture than cold air. MCU of man reclined on lawn chair basking in the sun. In hot weather the air sometimes feels close and we feel uncomfortable because the warm air contains an excessive amount of moisture. CU of glass of ice water being poured. When the air is cooled, as for instance when the air comes in contact with a glass of cold water it can’t hold as much moisture. The excess moisture simply condenses on the outside of the glass. MS of man drinking glass of water.