The material of the reference book is distributed in the main sections of the curriculum of the Ministry of Defense of Ukraine in science for students in grades 3 (2) and 4 (3). This allows you to independently select the necessary information and use it in the form in which students can perceive it: by providing specific figures and facts, comparing them with data already known to schoolchildren, using a number of data in order to summarize them, and the like. Handbook for teachers, primary school students, parents.