NOAA
Noaa: National Ocean Service: Education: Tides and Water Levels
A great resource for explaining and understanding tides. Find out what tides are and why it is so important to monitor them. This is an extensive tutorial followed by a set of review questions. All of the information can be downloaded as...
PBS
Pbs Learning Media: Coastal Geological Processes
This interactive resource adapted from the National Park Service describes the many forces that affect shorelines, including tides, weathering, erosion, and deposition. Includes background reading handout and discussion questions.