Tides Exercise - Biology 317 - Field Marine Biology (Due on Canvas before noon or else as hard copy by Friday, Feb. 2, 2024, at beginning when we meet at 1 pm at Cabrillo Marine Aquarium - 10 pts.)

It will be necessary for you to either print this page out in order to draw tide diagrams, also printing out a blank piece of graph paper (see step 3). You can do this all electronically but I still want you to hand in a printed final version of your completed assignment to me on Feb. 2.

This exercise introduces a phenomenon central to our course: the tides. Answer the following questions, using the tide table linked for: LA Tides monthly calendar. (Tips: You can always find this same link at the top of our Course home page and consider bookmarking this link in your web browser!). Note also that I might include a question on our first midterm exam that will challenge you to accurately draw at least one tidal cycle, including drawing the cycle and labeling both y- and x-axes (tidal height in feet and hours of at least one day, respectively) appropriately. You have been warned.
Note that you can select the month displayed, which is important below for comparing the first two Fridays of our semester.

To complete this exercise, it might be simplest for you to complete it on paper to turn in directly to me. It is fine to turn in a hand-written version with all the answers, numbered 1-9.
If you would rather complete it electronically, you could still scan your hard copy sheets to a single PDF format for upload to Canvas. It is also fine to refer to parts of one or more answers as an appendix on one or more separate pages at the end of your Tides Exercise, or even as a separate document if Canvas is letting you upload two documents. I am flexible in how you complete and submit this assignment, but please remember your name.

Name:

1. In the tide table linked above, find and list the times (AM/PM or 24-hour format) and tidal heights (in feet) for the four high or low tides for the 1st Friday of the semester. Repeat for the 2nd Friday of the semester.

1st Friday: a)____:____  _________ft. b)____:____  _________ft. c)____:____  _________ft. d)____:____  _________ft.

2nd Friday: a)____:____  _________ft. b)____:____  _________ft. c)____:____  _________ft. d)____:____  _________ft.

2. Navigate to NOAA's webpage with a flexible interface for displaying tides for Los Angeles and vicinity. Create two graphs, contrasting three-day (72 hour) complete tidal cycles. The first graph (A) should be centered on our first Friday of the semester, and the second graph (B) should be centered on the second Friday of the semester. of this semester. To center it on the Friday, you need to start a day before and a day after each Friday by adjusting the dates. After you adjust the dates, click on "Plot Daily" under "Update". I recommend that you make a screen capture of each graph, to refer to in Step 3.

3. Draw a reproduction of each graph carefully. Ideally, each graph should be drawn in about one half (top or bottom) of a piece of graph paper. (You can print out a blank graph paper page here.)
Your y axis should be tidal height in feet, with y-axis values ranging from -3 ft to about 8 ft. I recommend that you draw your x axis to cross the y axis at 0.0 feet. Your x axis should be spaced to span three days. Please label every six hours (i.e., 0, 6, 12, 18, 0, 6, 12, 18, 0, 6, 12, 18, 0), also labeling groups of these appropriately by day and date.

4. True____ False_____ (choose one) The tidal height changes in height more rapidly midway between high and low tide than it does at or near low tide.

5. What is the duration between the first Thursday's LLW and the 1st Friday's LLW tide? Please be as precise as possible.

6. Study what is mean by mixed tides in our text (please fine and read the tides section). Explain what this means in terms of the observed tidal cycles. Please note that the typical pattern is abbreviated in the following order: HHW, LLW, LHW, HLW, so the most extreme low tide directly follows the most extreme high tide each day. Apply these labels to each of your graphs.

7. Repeat steps 2-4 starting with the 2nd Thursday (i.e., make a graph for tides spanning three days, one week later).

8. Study the difference between "spring" and "neap" tides after reading the section on tides in our text. There are also good web sites that explain tides. Assign one of these terms, "spring" or "neap", to each of the graphs that you drew. Explain your labels ("spring" or "neap") in terms of the lunar cycle (i.e., new, first quarter, full, third quarter) in the following space:

 

 

 

 

9. In terms of how low the tides during our Friday afternoon field trips, how does the better of the 1st or 2nd Friday lower low tides compare with upcoming low tides (3rd to 15th Fridays)? (Hint: You can also consult our course field trip schedule here.)