Seasons how many

Many trees bear fruit, such as apples and cherries. They ripen toward the end of summer. Trees stop growing during the fall. The leaves of many types of tree, called deciduous trees, turn red, orange, yellow, or brown, before falling off. Winter is the coldest season. Many trees and smaller plants are bare and lie dormant, which means they are inactive. They will stay like this until spring. Toggle text. By Konstantin Bikos and Aparna Kher.

When do spring, summer, fall, and winter start and end? It depends on which definition you use and if you are north or south of the equator. The Earth's axis is slightly tilted in relation to its orbit around the Sun. This is why we have seasons. In most cultures, including all western countries, the year is commonly divided into four seasons:. Since the year has 12 months , each season lasts about three months. However, the dates when the seasons begin and end vary depending on whom you ask.

Two methods are most commonly used to define the dates of the seasons: the astronomical definition and the meteorological definition. In the northern hemisphere, the concept of autumn is associated with the harvesting of crops.

During this period animals gather food in preparation of the coming winter while birds migrate towards areas close to the equator to escape the dropping temperatures.

Winter occurs between autumn and spring and is the coldest season in the year. The word winter is derived from a Germanic word that refers to "time of water" due to the snow and rain that is experienced in the high and middle latitudes. The period extends from the winter solstice on December 21 st or 22 nd to the vernal equinox on March 20 th or 21 st.

The period occurs between June 21 st or 22 nd and September 22 nd or 23 rd in the southern hemisphere. The temperature variations are experienced mainly in the high and middle latitudes.

In the northern hemisphere, the concept of winter is associated with dormancy, animals especially those which hibernate become dormant during this time. The argument contends that temperature changes are experienced when the Earth moves closer or away from the sun at different periods during the year. The argument seems logical but it important to note that the decrease and increase in the distance from the sun are usually too small to cause significant changes.

The argument would be more fitting in the case of Mars which has a more elliptical orbit which means that it experiences more dramatic changes in the distance from the sun.

The northern hemisphere has larger amounts of ice sheets and land masses making it heavier compared to the southern hemisphere. To better understand how that works, imagine spinning a ball with a piece of gum stuck close to the top, the result is that the extra weight will lead to the ball tilting when spun. The angle of the Earth's obliquity usually cycles between A cycle lasts an estimated 41, years a factor that is thought to have been key to the formation of ice ages.

The earth is currently experiencing decreasing obliquity meaning that the planet will experience more moderate seasons including warmer winters and cooler summers. The glaciers on earth tend to grow when the obliquity is decreasing due to cooler summers that fail to melt the snow formed during winter. A tree lined road depicting the changes of the four seasons: spring, summer, fall, and winter.