Graphing Tides 3 · PDF fileGraphing Tides Source of Tidal Data ... explained basic tidal...
1
Graphing Tides Source of Tidal Data I get my tidal data from http://tbone.biol.sc.edu/tide Introduction Goals Student analysis using real data (well, real from a tidal calculator) to see the three tidal types and the effect of tidal resonance. Practice in graphmaking and interpretation Description Students plot high and low tide for Wilmington Beach (semi-diurnal), Pensacola (diurnal), Seatttle (mixed), and Joggins Wharf (semi-diurnal, but extreme tidal range), so they can see the important effect of location on tides. Context Used in an introductory oceanography course, where I have explained basic tidal theory: you should get two high tides per day (plus a few minutes). Students get all four locations to graph and interpret. I follow this lab with an activity on calculating tidal resonance period for the Bay of Fundy. In my general education Earth Science class, I give pairs of students one of these locations and then have the whole class report on results for all four locations. What follows in Roman is information or questions for the students. My answers/comments are in italics. Martin B. Farley, Geology & Geography, University of North Carolina at Pembroke Tides Plot the tidal record from each of the locations on the graph paper. You can plot multiple locations on one graph by marking data points with W,P,S,J. What tide type occurs at What is the elevation of mean high water? Wilmington Beach Semi-Diurnal 4.4 ft Pensacola Diurnal 1.6 ft Seattle Mixed 10.8 ft Joggins Wharf Semi-Diurnal 38 ft Which location has the smallest tidal range and which the largest? What is the tidal range at these locations? Pensacola is smallest (roughly 1.5 ft range), Joggins Wharf is largest (roughly 34 ft range) What is the significance of the negative tidal heights at some times? The tidal datum is MLLW (mean lower low water), which by definition is not the lowest level the ocean can reach. Figure 4. Windmill at the Joggins Museum The gray band shows the tidal range (white circles are the variability). Figure 1. Two of the datasets provided to students. Each location has about the same number of data points, so note different number of days. Students are told to plot until the data runs out or they fill up the supplied graph paper. Figure 3. Joggins, Nova Scotia at low tide. The position of high tide can be seen from the debris line on the beach at upper right. Figure 2. Tide levels at four locations illustrating semidiurnal, diurnal, mixed tide types and the large tidal range of the Bay of Fundy (Joggins Wharf). These are my Excel-plotted master graphs for ease of visibility. Students plot by hand. 0.0 1.0 2.0 3.0 4.0 5.0 6.0 28-Oct 29-Oct 30-Oct 31-Oct 1-Nov Height (feet) Wilmington Beach -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 30-Oct 31-Oct 1-Nov 2-Nov 3-Nov 4-Nov Height (feet) Pensacola -2 0 2 4 6 8 10 12 28-Oct 29-Oct 30-Oct 31-Oct 1-Nov 2-Nov Height (feet) Seattle 0 5 10 15 20 25 30 35 40 45 28-Oct 29-Oct 30-Oct 31-Oct 1-Nov Height (feet) Joggins Wharf Seattle, WA Day Time Height Unit Event 1 6:23 11.0 feet High Tide 1 11:46 5.0 feet Low Tide 1 17:16 10.9 feet High Tide 2 0:05 -0.6 feet Low Tide 2 7:09 11.3 feet High Tide 2 12:27 5.8 feet Low Tide 2 17:40 10.6 feet High Tide 3 0:38 -0.9 feet Low Tide 3 7:53 11.4 feet High Tide 3 13:09 6.4 feet Low Tide 3 18:05 10.2 feet High Tide 4 1:12 -0.9 feet Low Tide 4 7:38 11.4 feet High Tide 4 13:54 7.0 feet Low Tide 4 18:32 9.8 feet High Tide 5 1:49 -0.7 feet Low Tide Pensacola, FL Day Time Height Unit Event 1 9:24 0.2 feet Low Tide 1 23:23 1.6 feet High Tide 2 10:12 0.1 feet Low Tide 2 23:55 1.7 feet High Tide 3 11:00 0.0 feet Low Tide 4 0:31 1.7 feet High Tide 4 11:49 -0.1 feet Low Tide 5 1:12 1.7 feet High Tide 5 12:42 0.0 feet Low Tide 6 1:57 1.7 feet High Tide 6 13:37 0.0 feet Low Tide 7 2:45 1.6 feet High Tide 7 14:31 0.0 feet Low Tide 8 3:34 1.5 feet High Tide 8 15:19 0.1 feet Low Tide 9 4:23 1.4 feet High Tide 9 15:58 0.2 feet Low Tide Remains of Joggins Wharf--->
Transcript of Graphing Tides 3 · PDF fileGraphing Tides Source of Tidal Data ... explained basic tidal...
Graphing Tides
Source of Tidal DataI get my tidal data from http://tbone.biol.sc.edu/tide
Introduction
Goals
Student analysis using real data (well, real from a tidal calculator) to see the three tidal types and the effect of tidal resonance.
Practice in graphmaking and interpretation
Description
Students plot high and low tide for Wilmington Beach (semi-diurnal), Pensacola (diurnal), Seatttle (mixed), and Joggins Wharf (semi-diurnal, but extreme tidal range), so they can see the important effect of location on tides.
Context
Used in an introductory oceanography course, where I have explained basic tidal theory: you should get two high tides per day (plus a few minutes). Students get all four locations to graph and interpret. I follow this lab with an activity on calculating tidal resonance period for the Bay of Fundy.
In my general education Earth Science class, I give pairs of students one of these locations and then have the whole class report on results for all four locations.
What follows in Roman is information or questions for the students. My answers/comments are in italics.
Martin B. Farley, Geology & Geography, University of North Carolina at Pembroke
Tides
Plot the tidal record from each of the locations on the graph paper. You can plot multiple locations on one graph by marking data points with W,P,S,J.
What tide type occurs at What is the elevation of mean high water?
Wilmington Beach
Semi-Diurnal 4.4 ft
Pensacola
Diurnal 1.6 ft
Seattle
Mixed 10.8 ft
Joggins Wharf
Semi-Diurnal 38 ft
Which location has the smallest tidal range and which the largest? What is the tidal range at these locations?
Pensacola is smallest (roughly 1.5 ft range), Joggins Wharf is largest (roughly 34 ft range)
What is the significance of the negative tidal heights at some times?
The tidal datum is MLLW (mean lower low water), which by definition is not the lowest level the ocean can reach.
Figure 4. Windmill at the Joggins MuseumThe gray band shows the tidal range (white circles are the variability).
Figure 1. Two of the datasets provided to students. Each location has about the same number of data points, so note differentnumber of days. Students are told to plot until the data runs outor they fill up the supplied graph paper.
Figure 3. Joggins, Nova Scotia at low tide. The position of high tide can be seenfrom the debris line on the beach at upper right.
Figure 2. Tide levels at four locations illustrating semidiurnal, diurnal, mixed tide types and the large tidal range of the Bay of Fundy (Joggins Wharf). These are my Excel-plotted master graphs for ease of visibility. Students plot by hand.
0.01.02.03.04.05.06.0
28-Oct 29-Oct 30-Oct 31-Oct 1-Nov
Hei
ght (
feet
)
Wilmington Beach
-0.20
0.20.40.60.8
11.21.41.61.8
30-Oct 31-Oct 1-Nov 2-Nov 3-Nov 4-Nov
Hei
ght (
feet
)
Pensacola
-202468
1012
28-Oct 29-Oct 30-Oct 31-Oct 1-Nov 2-Nov
Hei
ght (
feet
)
Seattle
05
1015202530354045
28-Oct 29-Oct 30-Oct 31-Oct 1-Nov
Hei
ght (
feet
)
Joggins Wharf
Seattle, WADay Time Height Unit Event
1 6:23 11.0 feet High Tide1 11:46 5.0 feet Low Tide1 17:16 10.9 feet High Tide2 0:05 -0.6 feet Low Tide2 7:09 11.3 feet High Tide2 12:27 5.8 feet Low Tide2 17:40 10.6 feet High Tide3 0:38 -0.9 feet Low Tide3 7:53 11.4 feet High Tide3 13:09 6.4 feet Low Tide3 18:05 10.2 feet High Tide4 1:12 -0.9 feet Low Tide4 7:38 11.4 feet High Tide4 13:54 7.0 feet Low Tide4 18:32 9.8 feet High Tide5 1:49 -0.7 feet Low Tide
Pensacola, FLDay Time Height Unit Event
1 9:24 0.2 feet Low Tide1 23:23 1.6 feet High Tide2 10:12 0.1 feet Low Tide2 23:55 1.7 feet High Tide3 11:00 0.0 feet Low Tide4 0:31 1.7 feet High Tide4 11:49 -0.1 feet Low Tide5 1:12 1.7 feet High Tide5 12:42 0.0 feet Low Tide6 1:57 1.7 feet High Tide6 13:37 0.0 feet Low Tide7 2:45 1.6 feet High Tide7 14:31 0.0 feet Low Tide8 3:34 1.5 feet High Tide8 15:19 0.1 feet Low Tide9 4:23 1.4 feet High Tide9 15:58 0.2 feet Low Tide
Remains of Joggins Wharf--->
