This study explored students' conceptual understanding and conceptual growth regarding classical mechanics in the natural context of a Grade-level 10 science classroom. The purpose of the study was to determine the pervasiveness of a pattern observed in an earlier study in which learners initially gave evidence of scientifically valid knowledge structures but then returned or regressed to an earlier, primitive level of understanding. In the current study, concept mapping and interview methods were used to capture students' construction of knowledge patterns across a survey course designed to focus on some big ideas in physics. The analyses of mean ratings of student-generated concept maps and interview transcripts over three data collections did not consistently reveal the progression-regression patterns across the instruction as observed in the earlier study. The students' knowledge structures remained stable across the 10 weeks and remained unchanged 4 weeks after instruction ceased, suggesting that very little construction or restructuring of knowledge was taking place, and possibly worse, that the students' existing knowledge was not challenged sufficiently to promote the construction or reconstruction process. Implications of the alternative interpretations are discussed.