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Activity: Tidal Patterns Across the Globe

NGSS Science and Engineering Practices:

NGSS Crosscutting Concepts:

NGSS Disciplinary Core Ideas:

Materials

  • Table 6.3
  • Fig. 6.19
  • Fig. 6.20

 

Procedure

A. Identify tidal cycles

  1. Identify what type of tidal cycle occurred most commonly during September 2003 in
    1. Icy Bay, Alaska
    2. Acapulco, Mexico
       
  2. On a few days in September 2003, other types of tidal cycles occurred in both cities.
    1. What types were they?
    2. On what days did they occur?
       
  3. Overall, which city has stronger tidal currents? Explain the reasoning for your answer.

 

B. Link moon phases tidal events

  1. Identify the date of the full moon on Table 6.3. On each of the tide graphs (Fig. 6.19), find the symbol ◯ for this event.
     
  2. Identify the dates of all other moon phases on Table 6.3: first quarter moon, third quarter moon, and new moon.
  3. On each of the tide graphs (Fig. 6.19), add the appropriate moon phase symbols to the appropriate dates.
  4. Consider the dates of the different moon phases in the tide graphs (Fig. 6.19).
    1. How do the phases of the moon appear to affect tidal ranges in Icy Bay, Alaska?
    2. How does this pattern of tidal ranges in Icy Bay compare to tidal ranges in Acapulco, Mexico during the different moon phases?
  5. Identify in each city when spring tides and neap tides occurred. What event caused each of these tides?

 

C. Add moon orbital events to the tide charts

  1. Refer to Table 6.3. Identify the dates of the moon’s apogee and perigee.
     
  2. On each of the tide graphs, add the appropriate symbol (A or P) for these 2 events.
     
  3. How does the moon’s elliptical orbit appear to affect tide patterns in the two cities?

 

D. Add moon declination events to tide charts

  1. Refer to Table 6.3. Identify the day when the declination of the moon is farthest north (28.5˚ N).
     
  2. On each of the tide graphs, add the symbol (N) for this event.
     
  3. On each of the tide graphs, add the appropriate symbols for the remaining moon declination events.

 

Activity Questions: 
  1. Icy Bay, Alaska, is located near 60˚ N latitude. Acapulco, Mexico, is located near 17˚ N latitude. Based on their latitudes alone, how might you expect the declination of the moon to affect tide patterns in these two cities? (See Fig. 6.20 for a representative image, recall the moon’s declination as shown in Fig. 6.10.)
     
  2. According to the tide data in Fig. 6.19, how does the moon’s declination appear to affect tide patterns in Icy Bay and Acapulco throughout September 2003? How is this actual pattern different from what you predicted in question 1?
     
  3. Find the maximum tidal range during the month in each city by referring to Fig. 6.19. Considering the geographical positions of Icy Bay, Alaska, and Acapulco, Mexico (Fig. 6.20), give a possible explanation of why one city’s tidal range is much greater than the other.
     
  4. Describe the events that occurred on September 25–28. How did they affect the tide?
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.