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...
Other
Moon Tides: How the Moon Affects Ocean Tides
Discusses the different kinds of tides, high and low tides, lunar tide facts, questions people have asked about tides, and causes of tides.
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.