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Transcript of Audio:
Grade Level: 9–12
Subject Area: Earth Science
NOAA’s “Tides and Water Levels” Discovery Kit
NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS) Web page, with links to data and information about tides, water levels, currents, predictions, weather observations, forecasts, and harmonic constituents.
Online tutorial with additional details about ocean currents
National Science Education Standards
One 45-minute class period, plus time for student research
Explore how navigators of ships and boats predict and compensate for the effects of coastal ocean currents.
Ocean currents are caused by three driving forces. The first is tidal motion resulting from the gravitational attraction of the moon and the Sun. The second is wind motion acting on the ocean through friction with the ocean’s surface. Finally, when the density of one water mass is different from the density of another water mass, the more dense water mass tends to move beneath the less dense water mass (when this happens, the water masses are said to move toward “equilibrium positions”). Such density differences are the result of variations in temperature and salinity (the concentration of dissolved substances such as sodium chloride, salts of magnesium and calcium, etc.) among different water masses. Water movement caused by these differences is known as “thermohaline circulation.”
Regardless of their cause, ocean currents are critical to life on Earth, as they transport food materials, as well as certain life stages of some organisms (e.g., seeds, eggs, larvae, juveniles, adults) over thousands of miles. In addition, ocean currents have a major impact on global climate, transferring heat from equatorial regions to higher latitudes (e.g., the Gulf Stream in the Atlantic Ocean and the Kuroshio Current in the Pacific). At a much smaller scale, currents can be a serious issue for swimmers since strong “rip” currents can quickly move a swimmer away from the shore. Similarly, anyone who operates a boat in coastal waters needs to understand the movement of currents and how to handle their effects. Shipmasters, in particular, need accurate real-time information about coastal water movements to avoid dangerous and expensive groundings and collisions.
Providing this information is part of the mission of NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS).This Center:
CO-OPS also manages a national network of Physical Oceanographic Real-Time Systems (PORTS®) located in major U.S. harbors. The PORTS® network provides real-time information such as water levels, currents, air gap (the clearance between the water surface and the bottom of a bridge), weather data, and other oceanographic information to help mariners avoid groundings and collisions (visit http://tidesandcurrents.noaa.gov for more information on CO-OPS information and data products; and http://tidesandcurrents.noaa.gov/programs for more information on PORTS® and other CO-OPS programs) In this lesson, students will explore some of the information available through the CO-OPS program website, and will apply this information to hypothetical coastal navigation problems.
Students will complete Salinity and Tides worksheets and discussion questions.
Computers with Internet access
Lesson Plan File:
(entire word document containing complete lesson plan and supporting attachments)
Download Here (pdf, 355kb)
Student Work Description:
Student problem sheet for the "Ready, Set, Drift" lesson.
Sample of Student Work: