Most of the time, instructors of introductory physics limit their goals to students' acquisition of basic concepts and end-of-the-chapter problem solving efficiency. They overlook the development of students' science process abilities required for constructing scientific knowledge and approaching complex problems as scientists do. This goal is attainable and very valuable at the same time. This paper describes how learners improved their scientific abilities during the course of one semester and reports on the activities and facilitations that helped students in the process. We investigated how long it takes for novices to develop complex scientific abilities and whether the content and the context of the tasks affect the abilities that students demonstrate. We found that students need to conduct several cycles of scaffolded investigations to gain competence in the application of scientific abilities. Depending on the particular ability, a period of five to eight weeks of work is necessary to achieve it.