Technology integration in K-12 classrooms is usually teacher-centered and has insufficient impact on students' learning. The purpose of this project is to facilitate science teachers' use of information and communication technologies (ICTs) as cognitive tools to shift their practices from teacher-centered methods to constructivist, student-centered ones. This paper describes the outcomes and lessons learned from an application of design-based research (DBR) in the implementation and refinement of a teacher professional development (PD) program that is a key component of the project. The results revealed teachers' positive changes in their classroom practices and positive impact on students' ICT skills and science learning. Design principles for future professional development programs aimed at preparing teachers to adopt a cognitive tools approach are described.