Seasons+Causes-+stoney+and+evan

=I. The Cause of Seasons=

By Evan and Stoney Red Class Last Updated: June 11th, 2007

Note: Perspective - as seen from the Northern Hemipshere
Seasons are caused by the tilt of Earth's axis. Earth's axis is not straight, but instead it is inclined at an angle of 23.5 degrees. Earth's tilt (23.5 degrees) coupled with Earth's revolution causes the seasons.

As the Earth revolves around the sun, the Earth's axis is oriented either toward or away from the sun. When the Earth is oriented toward the sun, Wellesley experiences summer. When Earth's axis is oriented away from the sun Wellesley experiences winter.

If you are still confused watch this video. It provides an excellent visual.
=Watch This!!!!!=

media type="youtube" key="DuiQvPLWziQ"

While Earth is orbiting around the sun, Earth's axis does not suddenly tip one way or another to create the seasons. Instead the rotation of Earth's axis remains pointed in the **same direction** as Earth orbits around the sun. It is the location of the Sun with respect to the Earth's tilt which results in the seasons.

=II. Important Points=


 * 1) The Earth's tilt coupled with Earth's revolution causes the seasons.
 * 2) Earth's axis is titled at 23.5 degrees

=III. Aphelion and Perihelion=

The point in a planet's orbit where it is fartherest from the sun is called its aphelion, while the point nearest the sun is its perihelion. The earth’s aphelion occurs in the month of July, while its perihelion occurs in January, although the earth’s distance from the sun has little to do with seasons. Instead, the tilt of the earth on its axis causes seasonal climate changes. The speed at which the earth moves around the sun varies slightly depending on the position of the earth in its orbit—it moves faster at perihelion than at aphelion.



= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =IV. Important Dates=

Note: Remember to refer back to the video and text below it.
=V. Other Resources=


 * 1) Textbook - Chapter 25, //Earth's Motions Section IV Seasons on Earth (// pages 467 - 469)
 * 2) This link: http://www.enchantedlearning.com/subjects/astronomy
 * 3) Equinox Quiz

Great Website for Review ( I recommend clicking this link)
=VI. Quiz on Seasons=

Here, try this quiz from enchantedlearning.com to test your knolwdge about the seasons. I would suggest pritning this page out and writing down the answers. Answers are below. (Do not cheat you are only cheating yourself on the final exam).


 * 1.** Name the four seasons.


 * 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?


 * 3.** What is the tilt of the Earth's axis (in degrees)?


 * 4.** During which season do the Sun's rays hit the Earth at the most direct angle?


 * 5.** During which season are the days the shortest?


 * 6.** What is the name of the shortest day of the year (and the beginning of winter)?


 * 7.** What is the name of the longest day of the year (and the beginning of summer)?


 * 8.** What is the name of a day in which the day and night are of equal duration?


 * 9.** How many times each year do we have days in which the day and night are of equal duration?


 * 10.** What are the names of each of these days?

Quiz from EnchantedLearning.com - Great Website
=VII. Answers for Quiz=


 * 1.** Name the four seasons. summer, autumn (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)? 23.5 degrees

4. During which season do the Sun's rays hit the Earth at the most direct angle? summer

5. During which season are the days the shortest? winter

6. What is the name of the shortest day of the year (and the beginning of winter)? winter solstice

7. What is the name of the longest day of the year (and the beginning of summer)? summer solstice

8. What is the name of a day in which the day and night are of equal duration? an equinox

9. How many times each year do we have days in which the day and night are of equal duration? 2 times

10. What are the names of each of these days? the vernal equinox and the autumnal equinox

=VIII. Bibliography= =Works Cited=

“The Earth.” __Enchanted Learning__. 6 June 2007 . “The Seasons.” __Astronomy 161 the Solar System__. 6 June 2007 <[|http://csep10.phys.utk.edu////.html>.] Spaulding, Nancy E., and Samuel N. Namowitz. “Chapter 25 Earth’s Motions Section IV Seasons on Earth.” __Earth Science__. Ed. Ceanne Tzimopoulos and Christine H. Wang. N.p.: McDougal Littell, 1999. 467 - 469.