Ebbing the Tides
Introduction
After two days of fast sailing, with the winds helping with every bit, the watchman in the crow’s nest reports having spotted the first merchantship without an escort. With cheers and eager battlecries, the boat quickly maneuvers to a better position, and charges at the merchantship with complete surprise to board and overtakes the ship before it even has time to figure out what is happening. The treasures, provisions, and supplies are are hauled on board the vessel. Without further ado, the boatswain raises the sails and continue southwards.
The Captain’s Orders
Read the log book Ocean Tides to get a basic foundation of tides and their role in the oceans. If you need more assistance, there is a computer on the Captain’s desk. If you use the computer, make sure you make a note where you got your information. Answer the questions and complete the following tasks using the log book, a calculator, and the internet.
Objective
Assess the role of tidal forces on the earth.
Questions
- Download this image and label:
- Higher high water
- Higher low water
- Lower high water
- Lower low water
- Tidal range
- Tidal period
- Tidal datum means?
- MLW means?
- MLLW means?
- The period of a semidiurnal tide is?
- The period of a diurnal tide is?
- The definition of a semidiurnal mixed tide is?
- How long does it take the moon to orbit the Earth? What do we call that?
- The solid Earth then rotates once every 24 hours and 50 minutes under these bulges. Why the extra 50 minutes?
- Label Figure 1 and Figure 2 as spring tide or neap tide.
Figure 1. Moon-Sun-Earth system in-lineFigure 2. Moon-Sun-Earth system in-line - Which of the following is true of NEAP tides?
- Highest highs
- Lowest lows
- Which of the following is true of NEAP tides?
- Largest tidal range
- Smallest tidal range
- Which of the following is true of SPRING tides?
- Caused by constructive interference
- Caused by destructive interference
- Which of the following is associated with NEAP tides?
- half moons
- new moons
- full moons
- The Bay of Fundy in Nova Scotia, Canada has the highest tidal range in the world. What is the range in meters?
- List all the ways in which marine organisms are affected by the tides.
- What is the tidal pattern shown in Figure 3. Boston, Massachusetts?
- diurnal
- semidiurnal
- mixed
- What is the largest tidal range in Figure 3. Boston, Massachusetts?
Figure 3. Boston, Massachusetts tidal data for 11/2013 to 12/2013 - What is the tidal pattern shown in Figure 4. Galveston, Texas?
- diurnal
- semidiurnal
- mixed
- What is the largest tidal range in Figure 4. Galveston, Texas?
Figure 4. Galveston, Texas tidal data for 11/2013 to 12/2013 - What is the tidal pattern shown in Figure 5. Florida?
- diurnal
- semidiurnal
- semidiurnal mixed
- What is the largest tidal range in Figure 5. Florida?
Figure 5. Florida tidal data for 11/2013 to 12/2013
How to Submit Your Task
Answer the questions on a word processing document and label Figures 1 and 2. Once you have finished the assigned task, submit the document, Figure 1, and Figure 2 to the Captain’s dropbox.
