Developing the use of visual representations to explain basic astronomy phenomena

Several decades of research have contributed to our understanding of students’ reasoning about astronomical phenomena. Some authors have pointed out the difficulty in reading and interpreting images used in school textbooks as factors that may justify the persistence of misconceptions. However, only a few studies have investigated to what extent usual textbook images influence students’ understanding of such phenomena. This study examines this issue exploring 13-14 years old students’ explanations, drawings and conceptions about three familiar phenomena: change of seasons, Moon phases and solar/lunar eclipses. The research questions that guided the study were: RQ1) How are students’ explanations and visual representations about familiar astronomical phenomena affected by different imagesupport conditions? RQ2) How are students’ conceptions about familiar astronomical phenomena affected by different image-support conditions? RQ3) Which features of the used images most affected the students’ visual representations and explanations of familiar astronomical phenomena? To answer our research questions, we designed three instructional contexts under increasing support conditions: textbook images and text; teaching booklets with specially designed images and text; only text. To analyze students’ drawings, we used exploratory factor analysis to deconstruct drawings into their most salient elements. To analyze students’ explanations, we adopted a constant comparison method identifying different levels of increasing knowledge. To investigate students’ conceptions, we used a mixed multiple choice/true false baseline questionnaire. For RQ1, results show that the specially designed images condition was effective in helping students producing informed drawings in comparison to text-only condition for all phenomena, and more effective than textbook images condition when one considers seasonal change drawings. Concerning RQ2, the specially designed images condition was the most effective for all phenomena. Concerning RQ3, prevalent elements of astronomy images that affected students’ explanations and visual representations were: elliptical Earth's orbit, position of the Sun with respect to the Moon orbit, Sun, Moon and Earth alignment. Our findings confirm concerns about textbook astronomy images, whose features may interfere with the identification of the relevant factors underlying the phenomena. Moreover, findings of this study suggest that affordances of the specially designed images may play an essential role in scaffolding meaningful understanding of the targeted phenomena. Implications for teaching through and learning from visual representations in astronomy education are briefly discussed.