The Tides Lab: Lab #______

Name ______Date ______Period ____

Objective: to understand the relationship between tides and the phases of the moon

NOAA Tide explanation

The word "tides" is a generic term used to define the alternating rise and fall in sea level with respect to the land, produced by the gravitational attraction of the moon and the sun. To a much smaller extent, tides also occur in large lakes, the atmosphere, and within the solid crust of the earth, acted upon by these same gravitational forces of the moon and sun. Additional nonastronomical factors such as configuration of the coastline, local depth of the water, ocean-floor topography, and other hydrographic and meteorological influences may play an important role in altering the range, interval between high and low water, an times of arrival of the tides.

The most familiar evidence of the tides along our seashores is the observed recurrence of high and low water - usually, but not always, twice daily. The term tide correctly refers only to such a relatively short-period, astronomically induced vertical change in the height of the sea surface (exclusive of wind-actuated waves and swell); the expression tidal current relates to accompanying periodic horizontal movement of the ocean water, both near the coast and offshore (but as distinct from the continuous, stream-flow type of ocean current).

Knowledge of the times, heights, and extent of inflow and outflow of tidal waters is of importance in a wide range of practical applications such as; navigation, construction, and the establishment of standard chart datums for hydrography and for demarcation of a base line or "legal coastline" for fixing offshore territorial limits both on the sea surface and on the submerged lands of the Continental Shelf. (NOAA)

Vocabulary:

Neap Tide

Spring Tide

Tidal Range

Storm Surge

Continental Shelf

Semi-Diurnal Tides

Diurnal Tides

Mixed Tides

Procedure:

  1. Examine the data table or use the online excel spread sheet
  2. Fill in the remaining columns, “Average Daily Water Elevation”; “Average Daily Tidal Range” and “Phase of Moon”(sketch moons phases next to Phases of Moon Column)
  3. Make a graph plotting Time (in days) on the X axis and Average High Tide, Average Low Tide, Average Tide, and Tidal Range on the Y Axis (One Graph multiple data series)
  4. On the same Graph Draw the New, Full, 1ST and 3rd quarter moons above the correct date
  5. Label Spring and Neap Tides
  6. If not done in excel initially; complete steps 1-5 while using excel and make a graph using excel
  7. Remember to label your graph correctly

Discussion Questions: (Answer Questions on a separate piece of paper in complete sentences)

1.What relationships exists between high tides and the phases of the Moon?

2. What relationships exist between low tides and the phases of the Moon?

3. Explain how the Moon affects the tides (include the words, spring tide, neap tide, full moon, new moon, and quarter moon).

4. What is the relationship between tidal range and the phase of the moon?

5. What type of tide does King’s Point NY experience, diurnal, semidiurnal or mixed? Explain?

6. During what type of conditions would the largest tides occur (include both astronomical and weather related factors)?

7. Why does the Bay of Fundy experience such enormous tidal ranges?

8. What is a tidal bore? Provide at least 2 examples!

Conclusions: (Answer Questions on a separate piece of paper in complete sentences)

9. How would tides change around the world if the moon did not revolve around Earth?

10. How would tides change is the same side of the Earth faced the moon at all times?