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Question Set: Moon Declination and Tide Height

NGSS Science and Engineering Practices:

NGSS Crosscutting Concepts:

NGSS Disciplinary Core Ideas:

  1. Ensenada, Mexico is located at 31˚ N on the edge of the Pacific ocean basin (see the green star in Fig. 6.11 A). Valparaíso, Chile is located 33˚ S on the edge of the Pacific ocean basin (see the red star in Fig. 6.11 B).
    1. Graph the tidal height a person standing on the shoreline of Valparaíso, Chile, at 33˚ S would experience over the course of the same 24 hours as the person in Ensenada in Fig. 6.11 C. Use the same X- and Y-axes as in Fig. 6.11 C.
    2. What time(s) does Valparaíso experience its “high” high tide(s)?
    3. What time(s) does Valparaíso experience its low tide(s)?
    4. Compare your drawing to Fig. 6.11 C. Explain why the tidal graphs of Valparaíso and Ensenada are similar or different.
       
  2. Graph the tidal height a person standing on the shoreline at the equator in Ecuador would experience over the course of the same 24 hours as the person in Ensenada, Mexico in Fig. 6.11. Use the same X- and Y-axes as in Fig. 6.10 C.
    1. What time(s) does Ecuador experience its “high” high tide(s)?
    2. What time(s) does Ecuador experience its low tide(s)?
    3. Compare your drawing to Fig. 6.11 C and Question 1. Explain why the tide graphs from Ensenada, Valparaíso, and Ecuador are similar or different.
       
  3. Refer to Fig. 6.10. Note how the orbit of the moon is tilted at an angle to the plane of the earth’s equator. As the moon moves in its orbit around our planet, it eventually arrives at a point directly over the earth’s equator (generally twice per month). At these times, the moon’s declination equals 0˚. What would the tide graph look like at this time in the following locations:
    1. Ensenada, Mexico at 31˚ N latitude
    2. Valparaíso, Chile at 33˚ S latitude
    3. On the shoreline at the equator in Ecuador
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.