The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers living in Washington State. Each activity packet provides the teacher with a set of lessons dealing with a particular topic related to the oceans. Included are student worksheets, lesson plans, a vocabulary list, and a bibliography. This activity packet, designed for the junior high level, is an introduction for students to the nature of tides. It includes activities designed to aid the student in understanding the relationship between the tides and the position of the sun, moon and earth. Other activities aid students in reading tide charts and in making predictions about tides. The skills students learn are used in a final activity that examines tidal activity in Puget Sound. (TW)