Reasons for the Reasons for the SeasonsSeasons

Environmental ScienceEnvironmental Science

Chapter 13.1 NotesChapter 13.1 Notes

GraduateHavard GraduateHavard

Distance has Distance has NOTHINGNOTHING to do with Seasons!!to do with Seasons!!

In the winter, the Earth is In the winter, the Earth is 147,093,602 km away from the Sun.147,093,602 km away from the Sun.

In the summer, the Earth is In the summer, the Earth is 152,097,053 km away from the Sun. 152,097,053 km away from the Sun.

The difference between the two is The difference between the two is 5,003,451 km, (3.3 percent), and not 5,003,451 km, (3.3 percent), and not enough to cause the seasons. enough to cause the seasons.

Reason for Seasons # 1Reason for Seasons # 1Polaris (North Star)

As the Earth revolves around the Sun, the North pole tilts toward or away from the Sun.

Reason for Seasons # 2: Reason for Seasons # 2: ActivityActivity

Materials:Materials: a flashlight, ruler, and some graph paper a flashlight, ruler, and some graph paper

Procedures:Procedures:

1.1. Darken the classroom and shine the flashlight directly at Darken the classroom and shine the flashlight directly at the graph paper (12 inches from paper). Count how many the graph paper (12 inches from paper). Count how many squares receive light. If a square is more than half lit count squares receive light. If a square is more than half lit count it, less than half, don't count it. (Hint: Draw a circle around it, less than half, don't count it. (Hint: Draw a circle around the light portion of the graph paper and then count)the light portion of the graph paper and then count)

2.2. How many number of squares are lit?_______________How many number of squares are lit?_______________

3.3. Now shine the flashlight at the grid paper on an angle, Now shine the flashlight at the grid paper on an angle, but but from the same distance (12 inches from paper)from the same distance (12 inches from paper). Again . Again count the lit squares. count the lit squares.

4.4. How number of squares lit? ______________How number of squares lit? ______________

Reason for Seasons # 2: Reason for Seasons # 2: ActivityActivity

Analysis Questions:Analysis Questions:

1.1. What happened to the light as you What happened to the light as you shined it on an angle? shined it on an angle?

2.2. If the same amount of light is spread If the same amount of light is spread out over more squares, what would out over more squares, what would happen to the energy received by happen to the energy received by each square? each square?

  

Reason for Seasons # 2Reason for Seasons # 2 During the summer, the Sun is high in During the summer, the Sun is high in

the sky.  Therefore, rays of light from the the sky.  Therefore, rays of light from the Sun hit us more Sun hit us more directlydirectly, making the , making the sunlight more intense and warmer.  In sunlight more intense and warmer.  In winter, the Sun is low in the sky.  The winter, the Sun is low in the sky.  The rays of light are spread more thinly rays of light are spread more thinly ((indirectindirect), and they do not warm us as ), and they do not warm us as much.  much.  

                    Summer light               Summer light                  

      Winter lightWinter light

Reason for Seasons # 2Reason for Seasons # 2

Indirect Energy

Direct Energy

Reason for Seasons # 2Reason for Seasons # 2

Reason for Seasons # 2Reason for Seasons # 2

Reason for Seasons # 2Reason for Seasons # 2

New Jersey

New Jersey

Earth's yearly revolution, month-by-month.

When is Spring coming?? When is Spring coming?? Summer Solstice: 1Summer Solstice: 1stst day of summer in North day of summer in North

JuneJune Winter Solstice: 1Winter Solstice: 1stst day of winter in North day of winter in North

December December Fall Equinox: 1Fall Equinox: 1stst day of fall in North day of fall in North

September September Spring Equinox: 1Spring Equinox: 1stst day of spring in North day of spring in North

March March

Equinox – Equal day and Equal night. (12 hours of Equinox – Equal day and Equal night. (12 hours of daylight and 12 hours of night)daylight and 12 hours of night)

20122012

Spring Equinox: March 20Spring Equinox: March 20thth Summer Solstice: June 20Summer Solstice: June 20thth

Fall Equinox: September 22Fall Equinox: September 22ndnd

Winter Solstice: December 21Winter Solstice: December 21stst