1. A COMPARATIVE STUDY OF THE EXPLICIT
APPROACH AND ASEI-PDSI APROACH IN
TEACHING SCIENCE IN SWAZILAND
SECONDARY SCHOOL
By
Moses G. Mabuza
128529

2. 1.0 INTRODUCTION
Dvlpt of students’ NOS views – important
curr. and instr. goal - Vhurumuku (2010).
 SGCSE – aim to dvlp. ablilities that enhance
scientific knowledge and understanding.
 Understanding NOS – important in dvlpt of
scientific literacy.
 Literacy – perennial goal of sc. ed. (Seung,
Bryan & Butler ,2009)


3. INTRODUCTION CONT.
Explicit and implicit curr. & instr. approaches
– compared.
 Explicit approach – recommended
(Dekkers, 2006)


4. 1.1 STATEMENT OF THE PROBLEM
Understanding of NOS difficult to learners.
 Early research – inadequate NOS
understanding
(Iqbal, Saiqa & Rizwan, 2009)
 Therefore, efforts to improve


5. 1.2 PURPOSE OF THE STUDY
Investigate changes in learners
understanding of NOS.
 Compare ASEI-PDSI and Explicit tg.
Approaches.


6. 1.3 RESEARCH OBJECTIVES
1.
2.
To determine participants’ NOS ideas before
and after an instr. intervention.
To determine the changes brought by the
instr. intervention in participants’ NOS ideas.

7. 1.4 RESEARCH QUESTIONS
1.
2.
What are the students’ NOS ideas before
and after an instr. Intervention?
What changes (if any) does the intervention
bring in students’ NOS ideas?

8. 1.5 RESEARCH HYPOTHESIS
There is no significant difference between the
ASEI-PDSI and the Explicit approaches to
teaching the nature of science.

9. 1.6 SIGNIFICANCE OF THE STUDY
Awareness of NOS conceptions
 Utilize effective teaching approach


10. 1.7 DEFINITION OF TERMS (OPERATIONAL)
Nature of science:
- epistemology of science in relation to
nature of scientific knowledge and dvlpt
of
scientific knowledge


11. 2.0 LITERATURE REVIEW
Conceptual framework
Seung, Bryan & Butler (2009) – conception of
NOS has changed
NOS – epistemology of science
- values, beliefs and assumptions
- ideas about science

12. LITERATURE REVIEW CONT.
Components of NOS – empirical
- inferential
- subjective
- tentative
(Khishfe & Lederman, 2006; Lederman,
et.al., 2002; Urhahne, kremer & Mayer,
2011)

13. LITERATURE REVIEW CONT.
Khishfe & Adb-El-Khalick (2002) – naïve and
informed NOS views.
Lederman et.al., (2002) – inadequate and
adequate NOS understandings.

14. LITERATURE REVIEW CONT.
Empirical studies
Dekkers (2006)
 Explored how inquiry & reflection contribute
to NOS understanding.
 Purpose – find starting point for tg NOS
 Sampling – 22 science teachers and 79
learners (grade 7, 8, 9 & 11)

15. LIT. REVIEW CONT.
Intervention – engaged in inquiry and
products compared with work of scientists.
 Data collection – pre-post questionnaire
 Data analysis – responses categorised,
views established and frequencies
determined.
 Findings – sensible NOS views
- after intervention views improved


16. LIT. REVIEW CONT.
Khishfe & Lederman (2006)
 Compared 2 instr. approaches – integrated &
non-integrated.
 Purpose – investigate effectiveness of 2
instr. approches.
 Sampling – Urban high school in Chicago.
- 42 ninth grade st. from 2 intact classes

17. LIT. REVIEW CONT.
Data collection – two intact groups
- 5-item questionnaire
- random interviews
- intervention
- questionnaire & interviews
 Instruments – examined by experts and
piloted


18. LIT. REVIEW CONT.
Data analysis – participants profiles
- profiles categorised (naïve or
informed)
- views compared
 Findings – non-integrated approach
effective


19. LIT. REVIEW CONT.
Paraskevopoulou & Kiliopoulos (2010)
 Investigated teaching NOS through MillikanEhrenhaft dispute.
 Design – pre-experimental
 Sampling – 24 students (2nd grade of high
school)
- Physics and chose natural
sciences.

20. LIT. REVIEW CONT.
Instruments – open-ended questionnaire
(modified)
 Findings – after intervention NOS ideas
improved.


21. 3.0 METHODOLOGY
Design: pre- post-instructional intervention
Sampling
 Purposive volunteer sampling
 20 Form 4 learners doing natural sciences.
 10 female and 10 male
Instrumentation
 Form C (VONS) adapted by Vhurumuku (2010)
 Validity and reliability established already
 Permission to use instrument .

22. METHODOLOGY CONT.
Data collection
 Two equivalent groups
 5-item open ended questionnaire
 Teaching ‘Atomic structure’ to both groups
 Pre- and post-intervention questionnaire
 Random interviews (5 participants in each
grp)
5-item objective test

23. DATA ANALYSIS PROCEDURES
Mixed methods
qualitative
 Ideas classified as naïve or informed
- according to NOS aspects (i.e.
empirical,
tentative, inferential)
 Pre- and post-intervention responses
tabulated
 Interview response from transcripts
interpreted


24. DATA ANALYSIS CONT.
Quantitative
 Student t-test

25. ETHICAL ISSUES
Explain purpose of study to learners
 Participation voluntary
 Consent to conduct study


26. 4.0 DATA ANALYSIS AND RESULTS
PARTICIPANTS’ IDEA
NOS ASPECT
Pre-Instr. Ideas
Frequency
Post-Instr. Ideas
Frequency
n
n
%
9
4
45
20
3
2
15
10
4
2
20
10
0
1
0
5
0
0
5
25
1f. Science is based on observation and experiments and testing
hypotheses (empirically based)
1
5
5
25
1g. Science demands evidence
What is
science?
%
1e. Science is a body of knowledge and a way of finding things
1.
0
0
4
20
5
4
25
20
2
0
10
0
2c. Experiments are a way of testing hypotheses under controlled
conditions
0
0
4
20
2d. Experiment is a method of collecting data or evidence
5
25
4
20
2e. Experiments are not the only way used by scientists to develop
new knowledge
0
0
4
20
2f. Experiments are done to test new ideas
6
30
6
30
Naïve ideas
1a. Study of natural of physical world only
1b. Developed knowledge based on experiments and observations
only
1c. Science is based on proof only
1d. Other disciplines (e.g.history) do not use the scientific method
Informed ideas
2.The role and purpose
of
experiments in
science
Naïve ideas
2a. Experiments prove theory
2b. Experiments are the only way of discovering new information
Informed ideas

27. ANALYSIS AND RESULTS CONT.
3. Development of
scientific theories
Naïve ideas
3a. Theories never change because they have been proven
4
20
0
0
3b. Theories never change but get modified
3c. Theories can be proven by experiments
4
6
20
30
2
3
10
15
3d. Theories can change or be modified in the light of new
evidence
3e. Scientists always try to modify and make theories better
5
25
7
35
1
5
5
25
3f. Different scientists can come up with different theories
0
0
3
15
3
5
6
2
15
25
30
10
0
2
4
0
0
10
20
0
4e. Theories explain why things happen and laws describe
what happens
4f. Laws are based on observation and experiments
0
0
6
30
4g. Law is a universal expression of relationships between
variables, e.g. Newton’s laws, Boyle’s law
0
Informed ideas
4. Difference and
relationship between
theories and laws
Naïve ideas
4a. Theories do not change but laws change
4b. Theories become laws
4c. Laws do not change but theories change
4d. Both laws and theories do not change
Informed ideas
4
4
0
4
20

28. ANALYSIS AND RESULTS CONT.
5. Development of
atomic structure –
inference and
theoretical entities
Naïve ideas
5a. They saw atom using a microscope and other gadgets
3
15
0
0
5b. Scientists are certain that the atom is small and round like a ball
4
20
2
10
5c. Proved that atom is there using experiments
8
40
2
10
0
0
7
35
5
25
6
30
0
0
2
10
0
0
1
5
Informed ideas
5d. Used radiation (e.g. Rutherford), radio waves, X-rays, electron
beams
5e. Developed theory from experimental evidence (e.g. experiments
and observations on charges)
5f. Atomic theory is a model used by scientists to explain
experimental evidence
5g. Different scientists made the same conclusion about the structure
of the atom

29. DATA ANALYSIS AND RESULTS CONT.

NOS views improved after intervention (Table
1)

30. ANALYSIS AND RESULTS CONT.
Table 2a:
instruction
Group A participants with informed ideas of NOS pre- and postNOS ASPECT
Pre-Instr.
Frequency
Post-Instr.
Frequency
n
%
n
%
EMPIRICAL
7
70
9
90
TENTATIVE
4
40
8
80
INFERENTIAL
2
20
8
80
Table 2b: Group E participants with informed ideas of NOS pre- and post-instruction
NOS ASPECT
Pre-Instr.
Frequency
Post-Instr.
Frequency
n
%
n
%
EMPIRICAL
4
40
9
90
TENTATIVE
2
20
7
70
INFERENTIAL
3
30
8
80

31. ANALYSIS AND RESULTS CONT.
Interviews
Questionnaire item: Does the development of scientific knowledge require experiments?
P5: pre-instruction response: Yes it does, because you need tangible proof to be sure that
something in science is true.
P5: post-instruction response: Experiments are not a requirement, but one way of
generating necessary evidence.
Interviewer: Would scientific knowledge exist without experiments?
P5: interview response: Yes it would exist, because there are other ways of generating
evidence besides experiments such as observation of phenomena and making inferences.
Interviewer (probing): But, in your first questionnaire response you said experiments were a
requirement. What did you mean?
P5: interview response: No, I thought like that, but now after the lesson we had, I have
changed hence my response in the second questionnaire.

32. ANALYSIS AND RESULTS CONT.
Quantitative
Table 3:
Participants’ scores in the objective test
Group A scores (x1)
Group E scores (x2)
4
3
3
5
5
4
3
2
5
3
3
2
2
4
5
4
3
3
4
4
37
34

33. ANALYSIS AND RESULTS CONT.
Table 4
4
0.3
0.09
3
-0.4
0.16
3
-0.7
0.49
5
1.6
2.56
5
1.3
1.69
4
0.6
0.36
3
-0.7
0.49
2
-1.4
1.96
5
1.3
1.69
3
-0.4
0.16
3
-0.7
0.49
2
-1.4
1.96
2
-1.7
2.89
4
0.6
0.36
5
1.3
1.69
4
0.6
0.36
3
-0.7
0.49
3
-0.4
0.16
4
0.3
0.09
4
0.6
0.36
37
0
10.1
34
0
8.4

34. ANALYSIS AND RESULTS CONT.


35. ANALYSIS AND RESULTS


36. 5.0 CONCLUSION, SUMMARY AND
RECOMMENDATIONS
Summary
 Both ASEI-PDSI and Explicit approaches
improved NOS understandings.
 More improvement in grp A than in grp E.
 However, t-test – no significant difference
between the two approaches.

37. SUMM., CONC. AND RECOM. CONT.
Conclusion
 ASEI-PDSI and Explicit teaching approaches
almost equally effective in teaching NOS.
Recommendations
 Further research which will consider multiple
topics in science syllabus.

38. - THE END THANK YOU!
Babe Mabuza