School, particularly primary school, plays a special and unique role in education. It joins teachers and students together, in order to show children and youths the complex reality of the world. Educational processes implemented in the following institution can reflect knowledge transmission or can be based on transaction models. Education is stimulating, experimental and exploratory as it guides students to the world of forming questions, searching for answers and developing conclusions. Unfortunately, this model is rather uncommon in Polish primary schools. This publication presents how experimenting, used by teachers, could introduce 7-year-old students in the first grade of primary school, into the world of knowledge and natural science competence. It also shows how experimenting affects the level of students’ education and natural science competence. The research aimed for describing methods of experimenting with first grade students in science education as well as explaining the connection between applying experiments in science education and students’ level of skills and knowledge. The research used a method of pedagogical experiment - quasi-experimental testing based on initial and final measurement using practical tests. The study included 307 primary school first-graders. The studies have established that there are dependencies between experimenting in science education as well as knowledge and skills level among the first grade primary school students, taking into account subjects’ gender. At the end, conclusions were also drawn regarding the possibilities for more extensive use of experimentation in Polish schools.