The Transformative Effects of Guided Inquiry-based Learning on Scientific Knowledge of Vision

Figures & data

Table 1. Definitions of concepts

Guided inquiry-based learning (GIBL)	A pedagogical approach that promotes students’ learning of science through investigation. It helps students internalise scientific concepts by encouraging them to take responsibility for their learning (Bybee, 2014; Heng & Karpudewan, 2017).
Conventional instruction (CI)	An approach involving ‘transferring’ knowledge through verbal and visual explanations with little student involvement in meaning-making and higher-order thinking (McLaren & Kenny, 2015).
Facets of knowledge	Students’ ways of understanding contexts. These are students’ context-specific strategies for solving particular problems (Galili & Hazan, 2000; Minstrell, 1992). Facets are extracted directly from students’ responses to problems.
Facet abundance	The percentage of students who exhibited a particular facet in their response to a context. One facet might be observed in responses to two or more questions. In that case, the average facet abundance from each question was taken as the abundance of a given facet (Galili & Hazan, 2000).
Parameter t	t = –1 for an unscientific idea, and t = 1 for a scientific idea (Galili & Hazan, 2000).
Facet abundance before instruction (FAB)	The facet abundance calculated from the comparison/treatment group’s pre-test.
Facet abundance after instruction (FAA)	The facet abundance calculated from the comparison/treatment group’s post-test.
Facet gain (FG)	Calculated by subtracting facet abundance before instruction from facet abundance after instruction and multiplying by t (Galili & Hazan, 2000). FG = (FAA-FAB)t; t is introduced to avoid the possible occurrence of negative and positive FG from unscientific and scientific facets respectively that indicate the same thing, positive effect of instruction.
Scheme of knowledge	Facets of knowledge can be grouped into clusters, each of which corresponds to the same idea or physical mechanism, underpinning all facets affiliated with that cluster. This constitutes a scheme of knowledge that is less context-dependent and thus possesses a more inclusive meaning than a facet (Galili & Hazan, 2000). The researcher constructs schemes by identifying the fundamental patterns of the facets.
Scheme abundance	An average of the abundance of facets that exhibit a similar pattern.
Scheme gain	Calculated by subtracting scheme abundance before instruction from scheme abundance after instruction.
Spontaneous vision scheme	The absence of physical connection between the observer and the observed object or image (Galili & Hazan, 2000).
Inclusive vision scheme	Demonstration of a connection between the observer and the observed object or image using a light originating either in the eye or a non-luminous object. We called this scheme an inclusive vision scheme to indicate that the observer is included in the optical system, although incorrectly.

Table 2. Description of instructional strategies

Guided inquiry based learning (GIBL)

Conventional instruction (CI)

Teaching how to observe objects: Engage: The students tried to observe objects in a dark room. They reasoned why they could not see in the dark room. Explore: The students were asked to draw and explain, in groups, how light helps them to observe things. Their ray diagrams were checked. Explain: One student from each group explained the group’s ideas and drawings to the rest of the class. Students exchanged feedback and explanations between the groups and with the teacher. Elaborate: Flashlights and plane mirrors were given to the students to help them realise that light is entering their eye when observing an object. The teacher provoked class discussion with questions such as: ‘Why could you not directly observe the mirror while light falls on it?’; ‘Do you think objects other than mirrors reflect light to our eyes?’ Evaluate: Students were asked to draw how they observe luminous and non-luminous objects and then to share with their group and the rest of the class what they had drawn and understood.

A textbook-based ‘talk and chalk’ approach was implemented. The teacher mainly used lectures featuring illustrative ray diagrams. The teacher occasionally asked questions to motivate the students and to revise the lesson. Examples of questions raised were: ‘How do we observe objects?’; ‘How does light help us to observe things?’. Students were instructed to copy notes from the blackboard.

Table 3. Pre- and post-tests

Question (Q)	Pictorial representation
1. In the diagram, Abebe sees the tree. Draw arrows to show how the light from the sun helps him see the tree.
2. Almaz and her physics teacher are discussing seeing. Teacher: ‘Explain how you can see the book’. Almaz: ‘Signals go along nerves between the eyes and the brain’. Teacher: ‘Yes, this happens between the eyes and the brain. But, there’s some distance between the book and the eyes. Does anything happen between them? What would you answer? Draw and explain’.
3. In the figure, there are a converging lens, observers, object point O, and image point I. Which observer can see the image point? Why?
4. In the figure, there are an observer, a candle, and a plane mirror. How can the observer see the image of a candle that can be formed with a plane mirror? Explain in a drawing. A. If the observer changed his position to the right of the mirror, could he observe the image of the candle? Explain your answer. B. If the observer changed his position to the left of the candle, just in the same line with the candle, could he observe the image of the candle?

Table 4. Spontaneous vision scheme before and after instruction

Facets	Comparison (CI) group			Treatment (GIBL) group
	FAB^a (%)	FAA^b (%)	FG^c (%)	FAB^a (%)	FAA^b (%)	FG^c (%)
A. Nothing blocks vision.	65	48	17	68	20	48
B. The light illuminates the object/image so that the eye can look at the object/image.	33	18	15	43	16	27
C. The light illuminates the eye so that the eye can look at the object/image.	38	17	21	40	13	27
Scheme before CI = 45% Scheme after CI = 28% Scheme gain = –17%				Scheme before GIBL = 50% Scheme after GIBL = 16% Scheme gain = –34%

^a FAB, Facet abundance before instruction; ^bFAA, facet abundance after instruction; ^cFG, facet gain (FAA − FAB) × t, where t = –1 for unscientific ideas such as these.

Figure 1. A student’s model of observing an object.

Table 5. Inclusive vision scheme before and after instruction    

Facets	Comparison (CI) group			Treatment (GIBL) group
	FAB^a (%)	FAA^b (%)	FG^c (%)	FAB^a (%)	FAA^b (%)	FGI^c (%)
D. The eye sends rays to see objects/images.	45	37	8	39	12	27
E. The light should light up the object/image so that the eye can send rays to see it.	25	28	–3	21	18	3
F. The light should illuminate both the eye and the object/image so that the eye can send rays to see it.	23	35	–12	27	13	14
G. The object/image sends rays to the eye so that it can be seen.	23	33	–10	19	9	10
Scheme before CI = 29% Scheme after CI = 33% Scheme gain = 4%				Scheme before intervention = 27% Scheme after intervention = 13% Scheme gain = –14%

^a FAB, Facet abundance before instruction; ^b FAA, Facet abundance after instruction; ^c FG, Facet gain (FAA – FAB) × t, where t = –1 for unscientific ideas such as these.

Figure 2. Student models of an inclusive vision scheme.

Figure 3. Students’ models of how light is needed to light up either the eye or the object.

Figure 4. Students’ scientific explanations of vision.

Table 6. A scientific explanation of vision

The eye sees reflected light.	Abundance in comparison group (%)	Abundance in treatment group (%)
Light reflected from the object reaches the eye enabling observation of the object.	23	51
Light from the real image diverges and reaches the eye enabling observation of the image.	10	54
The virtual image is formed and seen simultaneously.	0	44
Average abundance (%)	17	50

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