Constructivist learning theory is based upon the tenets that students come to learning experiences with prior knowledge and experiences that the learner will choose from to make sense of the present situation. This leads to a mixture of understandings among students. This study proposed to reveal students‟ understanding of atomic structure and cell structure as well as the relationships between atoms and cells. High school students from one private school participated in a paper-and-pencil test to uncover conceptual understanding and content knowledge of atoms and cells. The 120 participants were from grades: 9 (13m, 15f), 10 (9m, 20f), 11 (21m, 17f), and 12 (17m, 8f). All 120 students took the paper-and-pencil test and 16 students (4 per grade) participated in a follow-up interview. Drawings were analyzed by individual characteristics then using groups of characteristics models classes were formed. Openended questions were scored holistically by rubric scores and then deconstructed into individual content statements. A limited number of findings follow. Students were more likely to draw a Bohr model. Freshmen were less likely to indicate living materials contained atoms and more likely to indicate forms of energy contained atoms. As students progressed through high school, details included in cells decreased. Students failed to recognize that the sum of the products from cell division will be larger than the original cell due to the two growth periods included in the division cycle. Students were often able to provide the correct yes or no answer to are atoms and cells similar, different, or related but the follow-up answers often included non-scientific conceptions. Recommendations include implementing instructional strategies that promote long-term retention of conceptual understanding and the underlying content knowledge. Design evaluation methods to monitor student understanding throughout a unit of study that go beyond traditional closed-ended questions. Many limitations related to this study suggest that results should not be generalized beyond the targeted population.

The purpose of this research was to develop an on-line two-tier diagnostic instrument that could be used to identify alternative scientific conceptions held by students and to ascertain the conceptual level at which students are functioning. The instrument was designed to identify alternative conceptions held in relation to concepts that underpin the objectives listed in each of the four content strands of the New Zealand Science Curriculum. The stem questions of the first tier were designed around the curriculum objectives for Levels 4, 5 and 6. Distracters for the second tier were developed from alternative conceptions identified from surveys, teacher predictions and telephone interviews. A 52 item instrument was built into a Microsoft Word format with drop down menu functionality, and then transferred into an on-line format on a web site. The instrument link was sent by email to a student sample in the age range of Year 9 to 11. The student responses were analysed by answer selection and alternative conceptions were identified and classified. The instrument proved to be an economical rapid response tool for identification of student alternative conceptions to inform the design and development of student science learning programmes. The instrument and the component two-tier items have the potential to be used as part of an item bank for formative assessment tests to enhance student learning in science. The on-line functionality of the instrument has the potential to provide the 21st century learner with formative self assessment opportunities to enhance personalized self-directed learning programmes.

The purpose of this study was to examine the conceptual understandings of 55 elementary preservice teachers for the concept of buoyancy. This study used Ausubel’s Assimilation Theory (Ausubel, 1963) as a framework for a 15-week intervention that used pre/post concept maps (Cmaps), pre/post face-to-face semi-structured interviews, and drawings as evidences for change of formation of cognitive structures. Using a convergent parallel design and mixed methods approach, preservice teachers’ conceptions were analyzed using these evidences. Results of the study show that preservice teachers held both scientific conceptions and misconceptions about buoyancy as a force before and after an instructional intervention. Of importance were the existence of robust misconceptions about buoyancy that included inaccurate scientific knowledge about the foundational concepts of gravity, weight, mass, and density. The largest gains in scientific knowledge included the concepts of gravity, surface area, opposing forces, and the buoyant force. These concepts were consistently supported with evidence from post-concept maps, post, semi-structured interviews, and drawings. However, high frequencies of misconceptions were associated with these same aforementioned concepts as well as additional misconceptions about buoyancy-related concepts (i.e., weight, density, displacement, and sinking/floating). A paired t test showed a statistically significant difference (t = -3.504, p = .001) in the total number of scientifically correct concepts for the pre-concept maps (M = 0.51, SD = .879) and post-concept maps (M = 1.25, SD = 1.542). The Cohen’s d effect size was small, .47. Even through gains for the pre/post concept maps were noted, a qualitative analysis of the results indicated that not only were there serious gaps in the participant’s scientific understanding of buoyancy, after the instructional intervention an increased number of misconceptions were presented alongside the newly learned concepts. A paired t test examining misconceptions showed that there was a statistically significant difference (t = -3.160, p = .003) in the total number of misconceptions for the pre-concept maps (M = 2.709, SD = 1.449) and post-concept maps (M = 3.363, SD = 2.094) after the intervention. The Cohen’s d effect size was small, .43. Taken together, these results revealed that, in general, the preservice teachers had understandings of buoyancy that align with children in preschool and elementary school (Biddulph and Osborne, 1983; Grimellini-Tomasini et al., 1990; Halford, Brown & Thompson, 1986; Hsin and Wu, 2011; Kohn, 1993; Rappolt-Schlichtmann et al., 2007; Yin et al., 2008). Based on these findings, implications for this study suggest that elementary preservice teacher candidates should be carefully screened to ensure they have mastered foundational scientific knowledge that they are expected to teach to children. As such knowledge is a prerequisite to the development of pedagogical content knowledge, it is unlikely that large numbers of robust misconceptions will be significantly reduced or eliminated during a science methods course that is designed to focus on pedagogical content knowledge.