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Seasons : 

Seasons By: Nikki Modha

What is a Season? : 

What is a Season? Unless you live near the Earth's equator, you have no doubt noticed that the weather changes during the year: it is hotter during the Summer, colder in Winter, and somewhere in between during Spring and Fall. These are the seasons, a division of the year marked by changes in the weather.

Continued… : 

Continued… In temperate and sub polar regions generally four calendar based seasons are recognized: spring, summer, autumn, winter.

What causes this? : 

What causes this? The Earth rotates around an imaginary line passing through the poles, called the axis. This line forms an angle (called the tilt) of 23.5° with the perpendicular to the orbit of the Earth around the Sun. As the Earth moves around the Sun, this axis stays always pointing in the same direction. This means that, during part of the year, the northern part of the Earth will lean more directly against the sun, and during other parts the southern part will.

What has this to do with Temperature? : 

What has this to do with Temperature? Well, when the northern hemisphere is leaning away from the sun, the rays coming from it hit this part of the Earth at a smaller angle than on other parts of the world. This means that the same amount of light is distributed over a larger surface, and therefore these places receive less heat than the others.

Continued... : 

Continued... The southern hemisphere is experiencing Summer, the northern hemisphere Winter. In half a year, the situation reverses, and it is now Winter in the southern hemisphere since that part of the earth is now leaning away from the sun.

Seasons : 

Seasons Seasonal weather differences between hemispheres are further caused by the elliptical orbit of Earth. Earth reaches perihelion (the point in its orbit closest to the Sun) in January, and it reaches aphelion (farthest point from the Sun) in July. Even though the effect this has on Earth's seasons is minor, it does noticeably soften the northern hemisphere's winters and summers. In the southern hemisphere, the opposite effect is observed.

Equinox : 

Equinox An equinox occurs twice a year, when the tilt of the Earth's axis is inclined neither away from nor towards the Sun, the Sun being vertically above a point on the Equator. Around the equinox, the night and day are approximately equally long.

Continued… : 

Continued… The vernal equinox occurs in late March (this is the beginning of spring in the Northern Hemisphere and the beginning of fall in the Southern Hemisphere) The autumnal equinox occurs in late September (this is the beginning of fall in the Northern Hemisphere and the beginning of spring in the Southern Hemisphere).

solstice : 

solstice A solstice happens twice each year, when the tilt of the Earth's axis is most inclined toward or away from the Sun, causing the Sun's apparent position in the sky to reach its northernmost or southernmost extreme.

Continued… : 

Continued… The summer solstice is one day in the year when the day is the longest and the night in the shortest. Winter solstice is longest night and shortest day. The solstices, together with the equinoxes, are connected with the seasons. In some cultures they are considered to start or separate the seasons while in others they fall in the middle.

How they relate to seasons : 

How they relate to seasons The summer solstice is when summer begins. The winter solstice is when winter begins. The spring equinox in when spring begins. The fall equinox is when fall begins.

Review On Seasons : 

Review On Seasons 1. Name the four seasons. Summer , Fall, Winter, Spring. 2. Are the Earth's seasons caused by the differences in the distance from the Sun throughout the year or the tilt of the Earth's axis? The Tilt of the Earth’s Axis. 3. What is the tilt of the Earth's axis (in degrees)? 23.45 degrees 4. During which season do the Sun's rays hit the Earth at the most direct angle? Summer

Continued… : 

Continued… 5. What is the name of the shortest day of the year (and the beginning of winter)? Winter Solstice 6. What is the name of the longest day of the year (and the beginning of summer)? Summer Solstice 7. What is the name of a day in which the day and night are of equal duration? An equinox 8. How many times each year do we have days in which the day and night are of equal duration? 2 Times 9. What are the names of each of these days? vernal and autumnal equinox

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