This work shows some results collected in the development of an innovative educational project conducted in the specific module of the Master Teacher Training in Secondary Education. This experience has involved 63 students of sciences and several teachers, obtaining numerous qualitative data from activities developed in the classroom. Such data have allowed us to analyze the conceptions and motivations of students about the teaching profession and some aspects that can influence on the improvement of education and professional development. Most students show a significant relationship between teacher professionalism and the acquisition of knowledge and skills useful for teaching, but the values, attitudes and motivations of teachers are also considered important to improve education.