This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on using an electric single pan analytical balance. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) identifying and explaining the function of each part required to operate the electric single pan analytical balance; (2) operating the balance to weigh accurately a sample object; and (3) using the balance to add desired weights of different substances to a container to determine the unknown weight of a sample. Each lesson contains objectives, recommended methods and locations for practice, performance criteria, equipment and supplies to perform a task, detailed step-by-step instructions for learning a task, and performance exercises. Two performance tests cover operating an electric single pan analytical balance and finding weights of substances added to containers. (CT)