The King of Tides

Links verified 1/1/2012

Written by Bill Byles

Introduction | Task | Process | Evaluation | Conclusion | Teacher's section

"OK, here's the deal." The gruff inspector snarled as he spoke to your team of detectives. "For a long time people have been blamin' things on the moon! People claim to be crazy because of it, lovers claim to be under its spell, and even hospitals blame the full moon for loaded emergency rooms." "Yeah!", one of the newer members of your team replied flippantly, "So what's new?" The rest of your team let out a low sigh. Now the whole team was in for it! "I'll tell you what's new, Mr. Smartypants," the inspector glowered at each of you slowly, "Now some nutcase has brought charges against the moon for causing the tides! And, its your job to bring me proof one way or another!" The inspector turned back toward his desk and we thought he was through. He wasn't! He turned back to your team, pointed his finger at you and said, "And you only have two weeks to solve the case. Now get started!"

If you are going to collect evidence against the moon, there are three things you must know:

1. What are tides?
2. What is the difference between spring tides and neap tides?
3. What are diurnal tides, semidiurnal tides, and mixed tides?

After you know the answer to each of the questions above, you will need to collect the following information:

• a record of tide levels for a calendar month from three different locations,
  • an Eastern United States location
  • a Western United States location
  • an Asian location
• a calendar of phases of the moon for the same calendar month.

With all of the above information available you must answer two questions;

• Can you find a pattern that will convince the jury that the moon is responsible for the tides?
• If the moon is guilty, does it have an accomplice which contributes to causing the tides?

Your first step will be to prepare a preliminary report answering the first three questions stated in the Task section. All of your information is to come from the Internet. Some of your work will be done from printed material which came from a web site, but other information must be obtained live from the Internet.

The following web page locations provide information which has been printed for use at a station without a computer. If there are enough computers in your class you may also get this information directly from the web sites. (Caution! Some of these web sites may have already come to the conclusion that the moon is guilty. You can not adopt that conclusion until you have proof in hand from section two.)

• NOAA's Oceanographic Products and Services Division has a very complete description of Our Restless Tides: a brief explanation of the astronomical factors which produce tides.
• The Department of Physics & Astronomy at the University of Tennessee in Knoxville has a very good lesson on tides with a good diagram of spring tides and neap tides.
• Michael J. Pidwirny, Ph.D., of the Department of Geography, Okanagan University College, British Columbia presents a very good summary of ocean tides [This expired link is available through the Wayback Machine Internet Archive. If the page doesn't load quickly click on Impatient? at the bottom right of the page.]

Once you feel that you can give the inspector a very complete description of the basic tide questions it is time to start collecting tide data about three sites. This information should be copied and pasted into a spreadsheet (you will find more about this in the Process section and in the Teacher's section). When you select a location you will see a data table of the last 2 days. To find the actual data for your project scroll to the bottom of the page where you will see "Prediction Options." Scroll down a bit to "Select presentation options," and use the pull down menu to change the length of time to display from 2 days to 4 weeks. In the next section, "Starting time and time display options," change the current month to the previous month. After making those changes, click on the gray button that is labeled, "Make prediction using options." Do the same for each location chosen.

1. Eastern United States location - Maine to Virginia | North Carolina to Florida Keys | graph of previous 3 days (not enough data)
2. Western United States location - Washington to California | graph of previous 3 days (not enough data)
3. Asian location - Northern sites (except Japan) | Japan | Southern sites | graph of previous 3 days (not enough data)
   (NOAA reduced their data presentation to 3 days. Thanks to Laura Neely, a teacher in Georgia, for finding a new source of tide data)

You must also collect moon phase information for the same calendar month as the one used while collecting tide data. It is recommended that you use both of the sources listed below. The first given an excellent visual overview of the month, and the second gives specific times and dates.

• Moon Connection offers a moon phases calendar showing moon phases for any month from 1930 to 2022. However, the calendar does not identify new moon, full moon, or any other phase. You must approximate that information from the calendar. Remember, first quarter moon is "light on the right."
• Star Date offers a moon phases calendar for any month from 1951 to 2015. They feature a warning that "this tool displays the approximate Moon phases for a given month."
• Current moon phase from the U. S. Naval Observatory time service department. You can check the moon phase for any time from 1800 to 2199. The current phase image is updated every four hours.

For the body of your report you must rely on data that you collect and evaluate. You will collected tide data for three locations. Now look at the data to discover what patterns exist. Notice that each day has at least three tide heights listed, and most have four. None have more or less. Your first step will be to copy the tide data for the month you have selected. Next paste this data onto a word processing document. The numbers will look like a jumbled mess. You must find a way to make sure that each line contains only one tide level reading. To see an example of manipulating the raw data, click here.

Another way to quickly reformat the data you have pasted into a spreadsheet is presented at Raw Materials for the Mind by the Landmark Project. Click and drag to highlight the data for the month you have selected. Copy the data. Open Excel and paste the data. All of the data for a single day goes into one cell. Highlight the column where the data went. From the Data menu and select Text to Columns... then click the Finish button in the pop-up window. The first day of the month will still need to be formatted, but all of the rest will be easier to work with. If reformatting is any problem, simply throw away the first day of that month.

Now that you have the data in a form that you can use, look for patterns. Compare the tide data with moon phase data. If you think you see a pattern at one location, try to verify the identical pattern at the other two sites. Your group must reach a consensus on this or you will never be able to convince the jury.

Uh oh... I hear the Inspector calling, I think he is ready for his report.

Your preliminary report to the inspector can be in one of two formats:

1. A PowerPoint slide show including images, graphs or tables in your answer to each question.
2. A web page written by your group including images, graphs or tables in your answer to each question.

Members of the group will share a common grade. This grade will be based on:

• the extent to which each group member participated in this project,
• the quality of support for your "guilty" or "not guilty" verdict,
• the completeness of your presentation,
• and the quality of your presentation.

	Low Tide (Beginning) 1	Sea Level (Developing) 2	High Tide (Accomplished) 3
Group Participation	Most of the work on this project was done by one group member.	One group member allowed other group members to do all of the work on this project	All members of the group contributed to this project.
Quality of Support	The group offered no support for their "guilty" or "not guilty" decision.	The group offered support for their "guilty" or "not guilty" decision, but did not find out if an accomplice was involved	The group offered a data pattern which supported their "guilty" or "not guilty" decision regarding the moon, and clearly identified an accomplice.
Completeness of Presentation	Tides were explained, but no decision was presented and no pattern was suggested to justify a "guilty" or "not guilty" decision.	Tides were explained, a "guilty" or "not guilty" decision was presented, but no pattern was suggested to justify a "guilty" or "not guilty" decision.	Tides were explained, a "guilty" or "not guilty" decision was presented, and a pattern was suggested to justify a "guilty" or "not guilty" decision.
Quality of Presentation	The group presentation was more style than substance. More emphasis was given to effects and animation than to the required content.	The group did a good job of presenting an argument to support a "guilty" or "not guilty" verdict. However, there were too many distracting sounds, animations or other visual elements.	The group presentation had interesting visual elements and did a thorough job of presenting an argument to support a "guilty" or "not guilty" verdict.

By this time you should have reached a decision supported by data. There is a guilty party and an accomplice was involved. However, the verdict is sealed and I am not allowed to reveal it to you. You must hope that your investigation into this matter was detailed enough to support a correct verdict. Are you frustrated by that? Don't be, that is the nature of science. No expert's word is more important that conclusions which you reach supported by sound data. Just because you don't receive a paycheck from some scientific foundation does not mean that you can not do the work of a scientist. What next? Find another project. Question the accepted viewpoint and see if the data you find offers support for your position or not.

As many prominent "experts" in science have observed; no amount of experiments prove anything "beyond a doubt," and only one well constructed experiment is required to disprove long accepted scientific dogma. Remember Galileo and the Leaning Tower of Pisa?

If you are unable to provide computer workstations for all teams in your class, set up workstations where printed material is available for group research on the basics regarding tides. Visit each of the following sites and print the web pages. Make certain that your computer was set to print the URL of each web site on the page your students will be using for research. That way they can document their findings, or make note of places where they can copy images to insert into their report. I recommend that you do not let students use copy and paste on the written portion of their report. Ask them to make notes and write their own summary.

• Our Restless Tides: A Brief Explanation of the basic Astronomical Factors which Produce Tides and Tidal Currents
• Lunar Tides - This site might work best as a printout. There are some good links for further study, but students following those links during this project might get lost or distracted.

Last updated January 1, 2012

Based on a template from The WebQuest Page.