With a view to active learning, that makes the students protagonist, responsible and aware of the learning process, the present study presents an experimental work designed to demonstrate the usefulness and validity of the scientific method as the basic element of teaching Life Sciences. The experimental research was implemented in two second-grade classes at a Primary School in San Donà di Piave (Italy). Its purpose was to test the potency of a teaching approach based on the scientific method, particularly the observationalcomparative method, in the teaching of Life Sciences, focused on the structure of the flower and the inflorescences. For this reason, it was decided that one of the two classes used the experimental method instead of a traditional teaching-learning method based on the oral transmission of contents. During the action, students were invited to use scientific tools in each lesson as magnifiers, stereoscopes, and specimens of flowers. Active teaching and direct observation of flower structures reinforced the concepts theoretically exposed. This way, the high teaching potential of integrating macroscopic and microscopic observations was also confirmed. The observational-comparative method is a key component of the study of Biology. For this reason, all the topics linked to the study of plants can be addressed through the use of this active methodology. This kind of approach can motivate students, making them active participants in their learning. The obtained results showed that using the scientific method and laboratory tools such as the optical microscope or the magnifiers, conceptualizations planned for fifth grade, can be met with success also in second grade, helping to reach the programmed goals optimally and often excellently, facilitating the achievement of competences such as the use of a correct scientific nomenclature. With this approach, the young students were motivated, stimulated, intrigued, and this potentially provides meaningful, authentic and transferable Lifelong Learning and the development of a scientific culture together with an early interest in the Sciences.