This publication is a teacher's guide for teaching ninth grade science in New York City Public Schools. Activities for four areas -- physics, chemistry, earth science and biology -- are included. Five years of experimentation under classroom conditions preceded the publication of this guide which is specifically designed to meet the needs of students of varying abilities. The activities represent a segment of a sequential, concept-oriented K-12 science curriculum for the New York City schools. In accordance with the stated objectives, a specific format is used throughout the guides. Special features of the format are: topical outline; sequential units in each of four science areas; outcomes listed for each lesson; logically developed classroom lessons with specific content, methodology and techniques; designated laboratory lessons including explanatory notes for the teacher and work sheets for the pupils; enrichment materials, such as assignments, questions, reports, and projects. (BR)