(EMS) Module Overview

Earth, Moon, and Sun Module Overview

It takes approximately 365 ¼ days for the earth to move around the sun. We get our year based on this movement. While the earth is revolving around the sun it is also spinning on an axis tilted at 23.5 degree. The spin of the earth is its rotation. We do not feel this motion; instead it appears as if the sun is moving. We observe the sun as it "follows a path". The path the sun traces is called the ecliptic. It is a result of Earth's orbital motion around the sun.

Essential Questions

  1. How do I explain the motion of objects in the day/night sky?
  2. What is the reason for seasons?
  3. What are the phases of the moon?
  4. What causes an eclipse?
  5. What causes the tides?

Key Terms

  1. Axis – An imaginary line that passes through Earth's center and North and South poles, about which Earth rotates.
  2. Rotation – The spinning motion of a planet about its axis.
  3. Revolution – The movement of an object around another object.
  4. Orbit – The path of an object as it revolves around another object in space.
  5. Latitude – The distance north or south from the equator, measured in degrees.
  6. Solstice – The two days of the year on which the noon sun is directly overhead at either 23.5 degrees South or 23.5 degrees North.
  7. Vernal equinox – The day of the year that marks the beginning of spring in the Northern Hemisphere.
  8. Autumnal equinox – The day of the year that marks the beginning of fall in the Northern Hemisphere.
  9. Eclipse – The partial or total blocking of one object by another.
  10. Solar eclipse – The blocking of sunlight to Earth that occurs when the moon is between the sun and Earth.
  11. Umbra – The darkest part of a shadow.
  12. Penumbra – The part of a shadow surrounding the darkest part.
  13. Lunar eclipse – The blocking of sunlight to the moon that occurs when Earth is directly between the sun and moon.
  14. Tide – The daily rise and fall of Earth's waters on shores.
  15. Phase - The appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. One of the different shapes of the moon as seen from the earth.
  16. New moon - The phase of the moon occurring when it passes between the earth and the sun and is invisible or visible only as a narrow crescent at sunset.
  17. Full moon - The moon when it is visible as a fully illuminated disk.
  18. First quarter moon - The phase of the moon which is most easily spotted by the casual observer. You see the moon in this phase in the south as the Sun sets.
  19. Third quarter moon - Three weeks after the new moon, we again can see half of the illuminated part. This is usually called third quarter, or last quarter moon.
  20. Waning crescent - A crescent moon moving towards a new moon.
  21. Waxing crescent - A crescent moon moving towards a full moon.
  22. Waning gibbous - More than half, but less than fully illuminated, and moving towards a new moon.
  23. Waxing gibbous - More than half, but less than fully illuminated, and moving towards a full moon.

 

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