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Asia-Pacific Forum on Science Learning and Teaching, Volume 18, Issue 1, Article 7 (Jun., 2017) |
In this research, we adopted the experimental research design with pre-test post-test control group. The participants of this study were 54 first-year university students at the biology department of Boumerdes University. These students come from various high schools in the country, where, they have study OG. The mean age of the subjects was 19.07 years. 88.4% of them are females. This high percentage of females is fairly representative at biology department. At our university, students are randomly assigned groups in equal in number. We randomly selected one group as the experimental group (EG) and another group was assigned as the control group (CG).
In other to achieve the objective of this study, two measuring instruments were used:
- Geometrical Optics Understanding Concept Test (GOUCT)
The GOUCT is a multiple choice test, which is used to identify the student misconceptions. It comprised 10 questions, which are selected and partially modified from the studies investigating students’ conception about vision, propagation of light, and imagery in refraction (Guesne, 1985; Goldberg and McDermott, 1986; Blizak and al., 2009). Each question offered 5 answers. Only one of them is correct. The correct answer was given one point, while a zero point was given to the wrong answer or a blank answer. Since the test contains 10 questions, the total score will be between 10 and 0. The test items were constructed in a way that every question reflects students’ misconceptions about optics concepts (see Table 1.). The content validity of the test was confirmed by three independent experts (teacher) in physics department. The internal consistency (Cronbach α) of GOUCT was 0.85.
Table 1. Questionnaire description
Question
Item
Description
-Q1
Vision
Utilised the alternative frameworks for seeing identified by Guesne (1985).
-Q2
Propagation of light in medium.
Using camera obscura (air exists inside).
-Q3
Propagation of light in vacuum.
Using camera obscura (air does not exist inside).
-Q4
Shadow
Ball between source of light and screen. The light source is very large.
-Q5
Shadow
Ball between source of light and screen. The light source is very small.
-Q6
Formation of Image by thin lens.
Image by a converged lens on a screen (half of a lens is covered).
-Q7
Formation of Image by thin lens.
Image by a converged lens on a screen (a centre of lens is covered)
-Q8
Formation of image by a plane diopter.
Looking straightly to the fish in the aquarium.
-Q9
Speed of light.
Speed of light in different mediums.
-Q10
Refraction
Using different color of light.
- Geometrical Optics Intrinsic Motivation Scale (GOIMS)
The GOIMS which was used in the present study was developed by the authors (Chafiqi, F. & Blizak, D., 2014). It had acceptable level in the present sample; internal consistency (mean alpha value α = 0.88) and temporal stability (mean test-retest consistency r= 0.77).
The scale includes 6 items and is scored on a 5-point Liker scale ranging from 1= "Strongly Disagree" to 5= "Strongly Agree." An example of one of the intrinsic motivation scale items reads, “I have a great desire to study geometric optics”. Accordingly, the total score of the GOIMS for individual participant ranged from 6 to 30.
Teaching Sequence Using History of Science (TSUHoS)
The sequence that we have elaborated has focalized specially about the eastern Islamic scientists’ works in the field of the GO. We summarize the parties of HoS presented to students during this sequence in the following paragraphs.
The philosopher Abu Ysuf Yaqub ibn Is-haq al-Kindi (801-866 AD) stating that any luminous object emits rays in every direction. He believed that all objects give of rectilinear rays that act upon the human eye and that the sun’s rays allow us to see. For Abu Nasr Muhammad Ibn Tarkhan ibn Awzalagh al-Farabi (870-950 AD) the sun imparts to the eye a light that illuminates it, and imparts to colors a light that illuminates them. It is not the action of vision which allows us to see, but the power of light and the sun which allows vision to occur. The eye is passive in the visual process.
The famous Abu Ali al-Hasan Ibn al-Haytham (965-1039 AD) has been the first who has differenced between physiological optics and geometrical optics (Rashed, 1992). He was opted for an experimental approach. The names of some optical components of the eye are indeed Ibn al-Haytham’s appellations: cornea (قرنية), retina (شبكية), Vitreous Humor (السائل الزجاجي) Aqueous Humor (السائل المائي). In his treatise (Khitab-al-Manazir), he explained the anatomy of eyes and defined his lens system. And he clarified many pounds about light. We summarized them in the list below (Rashed, 1992):
- the vision as the eye receives light rays;
- the eye, when looking at a strong light, feels pain and may be damaged (Ibn al-Haytham rejected the idea that the eye diffuses light);
- light propagates away from illuminated bodies in straight lines;
- in camera obscura the image is reverted;
- light illuminated the objects around us and the light rays reflected from the surfaces of these objects in all directions but only when a ray from each point, which perpendicularly faces the eye, that interacts with the eye to produce an image;
- the image is formed on the crystal and not at retina;
- that light must travel at a high speed;
- the light refraction is caused by the difference in speed of light propagation in various substances;
- the ray of light arriving perpendicular to the boundary between two different transparent media, was not bent;
- the magnification was due to refraction, the bending of light rays at the glass-to-air boundary and not, as thought before, to something inside the glass.
Johannes Kepler (1571–1630) has been impressed by Ibn al-Haytham’s experience using corrected camera obscura (pinhole camera). However, Kepler corrected Ibn al-Haytham’s theory about vision and showed that light rays were refracted through the eye’s humor to focus on the retina as an inverted image.
Concerning refraction, Claude Ptolemy adopts the model of rays emerging from eyes (Euclide). He discusses some experiments to measure the effects of refraction of rays on the surface of separation between transparent materials of different densities: air / water, air / glass, glass / water. He observed that the incident beam and the refracted beam are located in a plane perpendicular to the refraction surface and the perpendicular rays to the surface are not refracted.
For René Descartes (1596 -1650) the particles of light progressively meet more resistance when passing through different media. This led him to be the first scientist to publish the law of refraction (in 1637) or formula to describe the relationship between the angle of incidence and refraction when referring to light passing through a boundary between two different media such as air and glass. But it was Snell who technically made the first innovations.
Snell and Descartes studied the refraction phenomenon and stated that the speed of light is as high as the covered medium is dense. This hypothesis was contested by Fermat. He is the first who attributed indices to the media.
Fermat (1601-1665) conducted experiments which led to a theory about refraction. This was that the propagation of light in air is greater than in water, and briefly that the ratio of the two velocities is equal to the ratio between the sides of the angles of incidence and of refraction.
Furthermore Ibn al-Haytham described quantitatively the laws of refraction in his book (Kitab al-Manathir), but he did not give the mathematical relation. According to Sabra (1981), Ibn al-Haytham’s model could have been expressed by the constancy of the velocity perpendicular to the surface and the change of the velocity parallel to the surface. If Al Haytham could express this mathematically he would have derived a sine Law. However, in 1990 Rashed discovered the manuscript written by Abu Sad al-Alla Ibn Sahl in 984 on the Burning Instruments. He demonstrated that the Arabic optics engineer Ibn Sahl interested by the problem of the anaclastic (how curved mirrors and lenses would cause all parallel light-rays striking it to refract into a single focus) has shown «geometrically " that refraction of a medium is characterized by a constant ratio. So Rashed (1992) credited Ibn Sahl with discovering the law of refraction which is usually called Snell and Descartes’ law. He also, affirmed that Ibn Sahl is the first mathematician known to have studied lenses. In his treatise Ibn Sahl considered hyperbolic plan-convex lenses and hyperbolic biconvex lenses and he describes the law of refraction with a diagram. Rashed writes that the main aim of Ibn Sahl’s work was on finding a way to construct a burning instrument.
We believe the HoS can relive the concepts and give them more importance. that`s why, we prepared a document (in PowerPoint) on geometrical optics concepts regarding vision, propagation and refraction of light between antiquity and the 17th century. We started with the ideas of the Greeks soaps in ancient times (Pythagoreans, Ptolemi, Aristotle...). Then we insisted on the work of Ibn al-Haythem regarding vision and propagation of light. In the end, we presented the law of refraction (Ibn Sahl, Snell and Descartes).
Before presenting this work to students, the opinions of three experts were considered to improve the document and make it clearer and more relevant.
The teaching sequence using history of science (TSUHoS), that we developed, has taken two hours, in an artificial class. The teacher presented to the students, the document that we prepared (projection show data), at the conference room of the Faculty. At the beginning of the sequence, the students were asked to focus on contain of lecture and take notes. At the end of the sequence, the teacher opened a debate about the content of the documentary and encouraged student-to-student discussion.
We point out that the purpose of this sequence is to motivate students to learn and to destabilize their misconceptions about vision and refraction.
Initially, we conducted the pre-tests (GOUCT and GOIMS) to all students concerned by our research. Then we applied the TSUHoS to the experimental group only. After a week from the application of this sequence, students in both groups (experimental and control) followed the course of geometrical optics in conventional conditions using traditional teaching method (TTM). This teaching has continued for four weeks (six hours of lectures and six hours of tutorials). Then we asked the two groups to answer questions from the post-tests (GOUCT and GOIMS) in a classroom during normal academic schedule, always allowing the students enough time to fill in the instruments appropriately. Same instructors are given to both groups. The design of this study is presented in Table 2.
The tests, that we have built, were done in the language of instruction (French).
The data were compiled and analysed using the Statistical Package for the Social Science (SPSS) for Windows computer software (version 19). The results of the analysis were used to answer the research questions.
Table 2. Research Design of the Study
Groups
Pre-test
Application
Post-test
EG
GOUCT + GOIMS
TSUHoS + TTM
GOUCT + GOIMS
CG
GOUCT + GOIMS
TTM
GOUCT + GOIMS
