Seasons

1. Seasons

2. Earth’s Revolution: Revolution is the yearly orbit around the sun. Earth is a satellite of the sun. Our orbit is an ellipse. The sun is offset from the center of the ellipse. Distance between sun and Earth will change during Earth’s year.

3. Earth gets closest to the Sun on January 3 (yearly) Earth gets farthest from the Sun on July 4 (yearly)

4. Is this elliptical orbit causing the changing temperature on Earth? If it were, you would expect the warmest days in January. You know this isn’t the case in the northern hemisphere.

5. Even though Earth is closest to the sun in January, the over-all amount of energy Earth receives from the sun changes little throughout the year. However, the amount of energy any one place on Earth receives can vary quite a bit. http://www.youtube.co m/watch?v=82p-DYgGFjI

6. Earth’s Tilted Axis Earth is tilted 23.5 This tilt causes our seasons Daylight hours are longer for the hemisphere tilted away from the sun.

7. Another effect of Earth’s tilt is that the sun’s radiation strikes the hemisphere tilted toward it at a higher angle that it does the other hemisphere. Because of this, the hemisphere tilted toward the sun receives more electromagnetic radiation per unit area than the hemisphere tilted away.

8. A summer season results when the sun is in the sky longer and its electromagnetic radiation strikes Earth at a higher angle. Just the opposite occurs during winter.

9. Equinoxes Sun reaches equinox when it is directly above Earth’s equator, and the number of daylight hours equals the number of nighttime hours all over the world.

10. Neither the northern nor the southern hemisphere is tilted toward the sun. In the Northern hemisphere, the sun reaches the spring equinox on March 20 / 21….fall equinox on September 22 / 23. (southern hemisphere is opposite) These dates are the first days of spring and fall.

11. Solstice The point at which the sun reaches its greatest distance north or south of the equator. Summer solstice is June 21 / 22 and the winter solstice occurs December 21 / 22.

12. When the sun is at the summer solstice, there are more daylight hours than during any other day of the year. When it’s at the winter solstice, on the shortest day of the year, we have the most nighttime hours.

13. Earth Data Review Earth is an imperfect sphere that bulges slightly at the equator and is somewhat flattened at the poles. The rotation of Earth causes day and night. Earth’s tilted axis is responsible for the seasons you experience, and our revolution around the sun marks the passing of a year.