WEATHER

How's the weather? Weather is more than a conversation starter--it impacts human activitites, including food production, transportation, water supply, and recreation. Descriptions of weather are reported daily on the Weather Channel. You can even visit this site http://www.weather.com for an update on weather. Weather is the condition of the atmosphere at any given time and place; it is the combination of atmospheric variables--temperature, sunlight, moisture (humidity and precipitation), barometric pressure, cloud cover, and the wind. These components are used to describe the existing weather and typical changes in weather as the seasons progress, and to predict the development of storms and other hazardous weather conditions. Atmospheric pressure determines the direction and speed of the wind, and the wind carries air masses of varying temperature and moisture from place to place. This dynamic blanket of air is constantly moving and interacting.

Weather varies from day to day and from place to place, day to day, from season to season and over long periods of time. Weather is caused by the uneven heating of the atmosphere by the sun. As the sun heats the air, the air moves.The sun does not heat the earth evenly for several reasons. First, the earth is titled on its axis 23 degrees. The North Pole always points in the same direction in space as it rotates and as it revolves around the sun. Because the earth is tilted, some portions of the earth receive direct sunlight while other parts of the earth receive indirect sunlight. At some point in the earth's orbit, the Northern Hemisphere points directly toward the sun. At other times it points away from the sun.

When the Northern Hemisphere is pointing toward the sun, it received strong, direct sun rays. Therefore, the Northern Hemisphere heats up and experiences......GUESS WHICH SEASON? (Click once you have an idea.)




















SUMMER!

AND while the Northern Hemisphere experiences these direct sun rays during the summer months, the Sourthern Hemsphere is tilted away from the sun, receives indirect sun rays and the season winter.


The earth is also heated unevenly because of day and night and because the sun heats land and water at a different rate. During the day, the sun heats up the land faster than the water. However, during the night, the land cools off more quickly than the water which can hold its heat longer...REMEMBER THE PROPERTIES OF WATER!!!

The earth is heated unevenly because of the colors on the earth. The North and South poles recieve indirect light and much of the energy from the sun is reflected off the white snow. The land cannot get very warm. Land that is dark on the other hand, absorbs more heat energy retaining the heat from the sun.