Developing the use of visual representations to explain basic astronomy phenomena

[This paper is part of the Focused Collection on Astronomy Education Research.] 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 year old students’ explanations, drawings, and conceptions about three familiar phenomena: change of seasons, Moon phases, and solar or 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 image-support 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 and 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 Earth’s elliptical orbit; the position of the Sun with respect to the Moon orbit; and 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.

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Figure 1

Representation of the nonuniform distribution of solar light on Earth’s surface. Adapted from Ref. [38].

Figure 2

Representation of the nonuniform distribution of solar light on Earth’s surface with indication of the tilt of Earth’s axis. Adapted from Ref. [38].

Figure 3

Representation of Earth’s orbit around the Sun. Adapted from Ref. [38].

Figure 4

Representation of the Moon phases. Adapted from Ref. [68].

Figure 5

Image “Seasons 1,” designed to explain the role of Earth’s motion along its orbit around the Sun and of Earth’s axis tilt in the change of seasons. Translation of Italian labels: Sun (Sole), Earth (Terra).

Figure 6

Image “Seasons 2,” designed to explain the variable incidence of Sun’s radiation on Earth during the year. Translation of Italian labels: December 21^st Latitude 40° N (bottom left panel), June 21^st Latitude 40° N (bottom right panel).

Figure 7

Image “Phases,” designed to explain full and new Moon phases.

Figure 8

Image “S-Eclipse,” designed to explain solar eclipses.

Figure 9

Image “L-Eclipse,” designed to explain lunar eclipses.

Figure 10

S64 (group 3) preinstruction drawing about seasonal changes. Drawing aligns to model Distance 1.

Figure 11

S58 (group 3) postinstruction drawing about seasonal changes. Drawing aligns to model Orbit & Rays. Translation of Italian labels clockwise (summer, spring, winter, autumn). The dot represents Italy.

Figure 12

S29 (group 2) preinstruction drawing about seasonal changes. Drawing aligns to Distance 2 model. Translation of Italian labels: aphelion (left), perihelion (right).

Figure 13

S29 (group 2) postinstruction drawing about seasonal changes. Drawing aligns to Orbit & Tilt & Rays model.

Figure 14

Pre-post trends for the inclination-based drawings.

Figure 15

S35 (group 2) preinstruction drawing about Moon phases. Drawing aligns to model Sequence 2.

Figure 16

S11 (group 1) postinstruction drawing about Moon phases. Drawing aligns to model Orbit & Sun. Translation of Italian labels (clockwise from left): Moon sickles, Sun, new Moon, Moon sickles, full Moon.

Figure 17

Pre-post trends for Sun-included drawings.

Figure 18

S2 (group 1) preinstruction drawing about Moon phases. Drawing aligns to Sequence 1 model.

Figure 19

S2 (group 1) postinstruction drawing abot Moon phases. Drawing aligns to Orbit & Sun model. Translation of Italian labels (clockwise from left): New Moon, last quarter, full Moon, first quarter. Label at the center: Earth.

Figure 20

S53 (group 3) preinstruction drawing about solar eclipses. Drawing aligns to model Rays 2. Translation of Italian labels from left to right: Sun, new Moon, Earth.

Figure 21

S33 (group 2) preinstruction drawings about solar and lunar eclipse. Upper drawing aligns to SME model, bottom drawing aligns to SEM model. Translation of Italian labels: solar eclipse (upper drawing), lunar eclipse (bottom drawing).

Figure 22

Pre-post trends for the rays- and shaded-based drawings.

Figure 23

S39 (group 2) preinstruction drawing about lunar eclipses. Drawing aligns to model Shading. Translation of Italian labels from left to right: Moon, Earth, Sun.

Figure 24

S33 (group 2) postinstruction drawing about solar (upper) and lunar (bottom) eclipse. Upper and bottom drawings align to Orbit 2 model for each phenomenon. Translation of Italian labels: Earth, Moon, Line of nodes, Sun (upper drawing); Sun, Earth (bottom drawing).

Figure 25

Pre-post trends for change of seasons partial and correct explanations.

Figure 26

Pre-post trends for Moon Phases partial or correct explanations.

Figure 27

Pre-post trends for solar and lunar partial or correct explanations.

Figure 28

Pre-post trends for combined students’ drawings explanations about change of seasons.

Figure 29

Pre-post trends for combined students’ drawings explanations about moon phases.

Figure 30

Pre-post trends for combined students’ drawings explanations about solar and lunar eclipses.

Figure 31

Pre- and postinstruction average scores in the baseline questionnaire of the whole sample.

Figure 32

Students’ scores in baseline postinstruction questionnaire amongst groups. An asterisk indicates statistically significant differences.