AP Environmental Science


Seasons

The Earht's four seasons are parts of a year that cause changes in the temperature, wearther, and the length of daylight. every season lasts to about three months each. The changing of the seasons are caused by the tilt of the earth's axis. Seasonal changes occur later in coastal ranges. The axis is tilted in the same direction throughout the year; however, the earth orbits the sun which causes the earth to have these four seasons. Whichever hemisphere is tilted towards the sun experiences more hours of sunlight each day.  In Temperate and Polar regions, the seasons are pointed out by changes in the amount of sunlight which may cause animals to go into hibernation or to migrate, and plants to be dormant. Every season is quite noticeable because of the freaquent temperature pattern changes during the year.

Spring

Spring usually begins as early as February and usually ends about June. From the astronomical perspective, spring days lengthen from equinox to solstice. The axis of the earth is tilted toward the sun and the length of daylight rapidly increases in the nothern hemisphere. Blossoming of a range of plants most likely shows shows when it's spring. Many colder places do not experience spring until May, June or even December (for the outer Antarctica). Severe weather seems to occur the most during spring, the rain belt lies in the northern hemisphere, and the southern tropics experience their dry season.  Southern areas experience days that will usually start off hot and sunny while humidity builds up and then results in large thunderstorms.

Summer

Summer begins as early as June and ends early September, depending on the Northern Hemisphere. This season is the warmest season of the year with the longest days. Summer days, from the astronomical perspective, shorten from solstice to equinox which results in summer having the season with more hours of daylight. This season is very important for many social events, (outdoor activities). Summer Monsoons usually have a tendency to produce massive amounts of rain mostly because of the condensation of water vapor in the rising air.

Autumn

Autumn usually starts September and ends late November for the northern hemisphere. Autumn is noticeable once it starts to arrive because night time usually comes a lot earlier than expected. This season is very noticeable because of the dramatic color change in leaves and the sudden leaf fall. Autumn leaf color change is a phenomenon that usually effect the normal green leaves to range from red to yellow. This phenomenon is usually known by "fall colors" and "autumn colors". Autumn is not as warm as summer is because of the position the earth is prior to the sun.


Winter

Winter starts at December and ends late January or February in the northern hemisphere. Winter is known as the season with the shortest days and the lowest average temperatures. The higher altitudes and latitudes experience ice and snow. Night-time comes earliest for this time of the year. A rare meteorological phenomenon for winter is the ice fog. Ice Fog is any kind of fog where the droplets of water have frozen into extremely tiny crystals of ice. Winter starts with the winter solstice and ends with the vernal equinox.


Definitions

*Solstice-

*Equinox-

Documentation of Sources.
*http://en.wikipedia.org/wiki/Seasons  

*http://www.nasa.gov/worldbook/wbkids/k_season.html

*http://www.ndbc.noaa.gov/educate/seasons.shtml

*http://en.wikipedia.org/wiki/Spring

*http://en.wikipedia.org/wiki/Spring

*http://en.wikipedia.org/wiki/Summer

*http://en.wikipedia.org/wiki/Winter

*http://en.wikipedia.org/wiki/Autumn