Early childhood teacher training in Spain prepares educational professionals to work with children from birth to six years old. This stage is divided into two cycles: the first (from 0-2 years) and the second (from 3 to 6 years). Therefore, anyone trained in this field should possess professional skills across this entire age range. However, reality shows a bias towards training geared towards the older children (4-5 years). This is due to multiple factors, but primarily stems from the specific characteristics of children at these ages and the limited research on this period of human development. In this paper, we aim to present some science-based learning activities implemented with 1- and 2-year-olds. These activities were developed within a broader research project on science education in early childhood, involving university researchers, teachers, and educators working with this age group. The results show that it is possible to begin working on scientific processes at these ages by taking into account their individual characteristics. To illustrate this, we present two specific experiments: scientific diapers and the cardboard city. In the first, diapers were used as a familiar object to explore scientific concepts with 2-year-olds, and in the second, we were able to observe the differences between 1- and 2-year-olds. These results are fundamental for initial teacher training, since future teachers must also possess scientific competencies relevant to these age groups.