In the study herein, Technological Pedagogical Content Knowledge (TPCK), a framework that extends the conceptualization of Pedagogical Content Knowledge, was adopted in order to teach three computer science concepts, namely, "Data," "Processing," and "Information". Technology Mapping, a method proposed in the literature for developing TPCK, was used for rethinking the instructional design of the unit "Data-Processing-Information", so that Excel could be adequately utilized for teaching it. In particular, the technical affordances of Excel were used in a powerful pedagogical way in order to eliminate learners' existing misconceptions about the three concepts. Twelve eighth graders, five girls and seven boys, participated in the study. Students had basic computing skills, but no prior knowledge about how to use Excel. The classroom teacher chose to use Excel, because it is a tool that enables quick data entry, real-time data processing, as well as immediate visualization of the outcomes. The duration of the lesson was 45 minutes. According to the results, the framework of TPCK and the Technology Mapping approach proved to be effective for teaching the three concepts and for correcting students' related misconceptions.