This manual as a whole is a series of manuals on the methodology of physics for a seven-year secondary school, compiled by the author for the thirtieth anniversary of the Soviet school on the basis of his twenty-five years of experience working with physics teachers and students of pedagogical universities. The purpose of the series is to familiarize teachers and future teachers (students of pedagogical and teacher's institutes) with all the various types of knowledge and skills that are necessary for the successful teaching of physics in a Soviet school.