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Earth’s Seasons

Objective:

I can demonstrate the relative positions of the sun and Earth during the solstices and equinoxes and to examine the characteristics that cause the conditions experienced on Earth during those days.

 

Learning Standard:

ES 11. Explain how the tilt of the earth and its revolution around the sun result in an uneven heating of the earth, which in turn causes the seasons.

Seasons Notes:

The tilt of the Earth (23.5 degrees) causes the sun to hit the Earth at different angles causing uneven heating (seasons).  Look at the diagram below showing how on the vernal (spring) and autumnal (fall) equinoxes, the sunlight strikes the equator at a 90 degree angle and concentrates the sun’s heat energy in a small surface area.  The farther north (or south) you get from the equator, the sunlight strikes Earth at angles less than 90 degrees (45 degrees at the tropics and 30 degrees at the arctic circle) which distributes the sun’s heat energy over a larger surface area.

Carefully observe the angle of sunlight and size of surface area:

Solar Angle

 

 

As the Earth revolves (orbits) the sun, different parts of the Earth receive the direct sunlight.  In the northern hemisphere, on summer solstice (June 21/22) the sun’s direct rays strike the Tropic of Capricorn and the northern hemisphere experiences summer. The norther hemisphere also experience the longest daylight hours at this time.  On winter solstice in the northern hemisphere (December 21/22), the sun’s direct rays strike the Tropic of Capricorn and the northern hemisphere experiences winter (due to lower angle sunlight striking in the north).  The norther hemisphere experiences the shortest daylight hours at this time.

On the equinoxes, direct sunlight strikes the equator and both hemispheres experience spring or fall.

 

seasons

Always focus on:

1.  tilt of Earth’s axis

2.  direction of Earth’s orbit

 

 

Post-Lab Questions:

1. What causes the seasonal changes on Earth?

2. During the summer solstice in the Northern Hemisphere, how many hours of daylight does the North Pole have?

3. During the winter solstice in the Northern Hemisphere, how many hours of daylight does the North Pole have?

4. During the Vernal and Autumnal Equinoxes, how many hours of daylight does the North Pole have?

5. When analyzing a diagram of the seasons, what two characteristics do you have to focus on to determine which part of the diagram represents each season?

6. During which month is Earth closest to the sun?

7. Describe day and night in terms of time during the summer solstice in the Northern Hemisphere.

8. Describe day and night in terms of time during the winter solstice in the Northern Hemisphere.

9. Describe day and night in terms of time during the equinoxes all over the earth.

10. Where on Earth do the sun’s most direct rays fall during the summer solstice in the Northern Hemisphere?

11. Where on Earth do the sun’s most direct rays fall during the winter solstice in the Northern Hemisphere?

12. Where on Earth do the sun’s most direct rays fall during the vernal and autumnal equinoxes?

 

 

 

Jump To:

Space Technology

Electromagnetic Spectrum (EMS)

Solar System

Gravity

Earth’s Seasons

Moon Phases

Eclipses

Tides

Stars & Galaxies

Study Guide:  Unit Test

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