Proceedings of the NARST 2009 Annual Meeting
EXAMINING THE EFFICACY OF AN EXPLICIT AND REFLECTIVE COURSE
ON PRESERVICE SECONDARY SCIENCE TEACHERS’ CONCEPTIONS OF
NATURE OF SCIENCE

The purpose of this study was to examine the relative efficacies of explicit and
reflective instruction using targeted activities and readings in a graduate-level
nature of science (NOS) course for preservice secondary science teachers.
Seventeen preservice teachers participated in this study. Participants responded to
an open-ended questionnaire designed to assess their conceptions of NOS before
and after the course intervention. Following the administration of the
questionnaires a sample of participants was interviewed to validate their responses
to the open-ended questionnaire. Interview data, in addition to artifacts collected
during the course, were used to examine links between changes in NOS
conceptions and course activities and readings. The data reveals an overall
pattern concerning the relative degree of change of NOS conceptions over the
course intervention and the number of explicit and reflective activities and
readings. A combination of targeted activities and readings taught in an explicit
and reflective way most directly affected the participants’ conceptions of NOS.
Those aspects of NOS taught using targeted readings alone showed less
development over the course. The findings provide further understanding of the
link between NOS pedagogy and preservice secondary science teachers’
development of NOS conceptions.
Ron Gray, Oregon State University
Nam-Hwa Kang, Oregon State University

Introduction
The nature of science (NOS) has long been advocated for as an essential element of
secondary science education. It occupies a central role in the various reform efforts, such
as Project 2061 (American Association for the Advancement of Science [AAAS], 1990,
1993) and the National Science Education Standards (National Research Council, 1996)
and has been thoroughly studied by science education researchers over the past several
decades (Lederman, 2007). NOS has been defined as the epistemology of science, a way
of knowing, or the values and beliefs fundamental to the development of scientific
knowledge (Lederman, 1992). On an academic level defining the components of NOS
has been contested. Schwartz and Lederman (2002) state, “there is not a single ‘nature of
science’ that fully describes all scientific knowledge and enterprises – various
representations of NOS have been affirmed by historians, philosophers of science,
science educators, and others” (p. 207). However, some common tenets of NOS do exist
at a K-12 level (Lederman & Lederman, 2004; Osborne, Collins, Ratcliffe, Millar, &
Duschl, 2003). Common NOS descriptions often include characteristics such as
empirically-based, tentative, subjective, creative, unified, and culturally and socially
embedded. Individuals with sophisticated understandings of NOS can recognize and

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distinguish between observations and inferences as well as facts, laws, and theories and
are able to utilize scientific processes, such as observation, classification, and prediction,
in a flexible manner during scientific investigations.
If an adequate understanding of NOS is our goal for students, then teachers’ sophisticated
understanding of NOS is a necessary though not sufficient condition (Lederman, 1992,
1998). Studies have shown that teachers often hold positivistic views of science which,
in turn, are communicated to their students (e.g., Gess-Newsome, 1999). This positivistic
view of science limits a teacher’s ability to develop and implement lessons that will affect
their students learning of NOS as well as the content of science (Kang & Wallace, 2005).
Therefore, it is important for teachers to understand NOS before they can effectively
address it in their classroom (Bartholomew, Osborne, & Ratcliffe, 2004). Furthermore,
teachers’ understanding of NOS should go beyond being able to define and assess NOS
goals in the classroom; they should be able to develop sound pedagogical practices
related to NOS to be effective in student learning (Bartholomew et al., 2004).
In an effort to prepare teachers with sophisticated knowledge of NOS, there have been
studies about preservice science teachers’ learning of NOS as well as pedagogical
approaches. In terms of NOS pedagogy for preservice teachers, three approaches have
been used and studied (Lederman, 1992, 1998):
Historical approach. An historical approach can be taken in which NOS is taught
through the incorporation of case studies in the history of science in order to enhance
students’ views of NOS. While some studies do report significant changes in NOS
understandings (e.g. Lin & Chen, 2002), the results are inconclusive (Khishfe & Abd-El-
Khalick, 2002).
Implicit approach. The second approach previously studied is the implicit approach in
which curricula assumes that students will enhance their NOS conceptions simply by
participating in an inquiry-based activity (Lederman & Abd-El-Khalick, 1998; Schwartz,
Lederman, & Crawford, 2004). In this approach no explicit attention is paid to NOS.
Rather, it is assumed that student understandings will develop as a natural consequence of
engaging in the activity (Schwartz et al., 2004). Research has shown, however, that
students do not develop more sophisticated NOS conceptions as a by-product of engaging
in inquiry-based activities (Khishfe & Abd-El-Khalick, 2002).
Explicit-reflective approach. The explicit approach views NOS as a cognitive objective
(Lederman, 1998) that is explicitly planned for in a way that draws students’ attention to
NOS. This means deliberately designing lessons to address specific components of NOS.
Thus, while an explicit approach to teaching NOS engages students in activities, it also
involves purposeful instruction of NOS (Schwartz & Lederman, 2002). Of equal
importance is reflective teaching which helps students make connections between the
activities and the targeted components of NOS (Khishfe & Abd-El-Klahick, 2002).
When implementing this approach, the instructor explicitly introduces the students to
targeted NOS aspects and then provides them opportunities to reflect on these aspects
during and after the activity. In addition, Lederman and Lederman (2004) explain that
while some students may reflect on an instructional activity independently, the most
effective way to ensure reflection for all students is to develop questions and carefully
plan their placement within the activity to elicit reflective instruction.

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Research suggests that NOS instruction is most effective when it is both explicit and
reflective in character. For instance, Abd-El-Khalick (2001) and Abd-El-Khalick and
Akerson (2004) used an explicit, reflective approach to teach NOS to prospective
elementary teachers. The authors reported significant improvement in multiple aspects of
NOS and concluded that the explicit, reflective approach to instruction was successful.
Khishe & Abd-El-Khalick (2002) emphasize that:
the term ‘explicit’ … does not refer to didactic or explicit teaching strategies, but
is meant to highlight the notion that NOS understandings are cognitive
instructional outcomes that should be intentionally targeted and planned for in the
same manner that abstract understandings associated with high-level scientific
theories, such as evolutionary theory and atomic theory are intentionally targeted.
(p. 555)
The purpose of this study is to examine the relative efficacies of explicit and reflective
instruction using targeted activities and readings in a graduate-level NOS course for
preservice secondary science teachers. This study is part of a larger study that examines
the development of student conceptions of NOS over the course of a teacher preparation
program.
Explicit and Reflective Instruction in the Graduate Level NOS Course
The NOS course was a four-week intensive summer course consisting of fifteen 3-hour
class sessions, 12 of which were applicable to the current study. The overall objective of
the course was: (a) to introduce the concept of NOS with the explicit intent to further
develop preservice teachers’ conceptions of science, (b) to provide experience with
inquiry-based activities that explicitly address NOS, and (c) to explicitly address the
teaching of NOS in the K-12 science classroom. The purpose was for the participants to
gain an understanding of NOS consistent with the current reform documents. In
particular, the aspects of NOS highlighted in Science for All Americans ([AAAS], 1990)
were used as the framework for the course as they best represented the state and local
standards the preservice teachers would be expected to follow in their teaching.
Each session the preservice teachers were assigned readings and reflective journals to
achieve the course objectives (Table 2). During the sessions, the students discussed the
readings in regards to targeted aspects of NOS and participated in activities designed to
address NOS conceptions. Activities included “the Cube activity” (National Academy of
Sciences [NAS], 1998), “Tricky Tracks” ([NAS], 1998), “Dino Facts” (Scotchmoor,
1997), and “The Great Fossil Find” (Randak & Kimmel, 1998), which are described in
detail below. While it is possible to use these activities and readings to explicitly target
many aspects of NOS, in the context of the course each addressed certain aspects of NOS
as noted in Table 3. In all discussions and activities, the instructor made explicit
references to relevant aspects of NOS and provided reflective questions targeting those
aspects.
In conjunction with explicit and reflective instruction, historical examples were utilized
to describe and reinforce targeted aspects of NOS. Pertinent aspects of the philosophy of
science were also discussed including a comparison of the views on science of Francis
Bacon, Karl Popper, and Thomas Kuhn. A modified version of the philosophy of science
card exchange activity (Cobern & Loving, 1998) introduced the relevant philosophical

4
ideas discussed in the course. This activity allowed explicit discussion and reflection on
a wide variety of philosophical stances concerning science. Near the end of the course,
the topic of evolution was examined as a contextualized example of NOS pedagogy.
Students in the course wrote daily reading journals, a summative essay on their views of
NOS in the context of science teaching, and a science-in-action book report detailing
major NOS themes present in scientific research described in popular accounts (e.g.,
James Watson’s The Double Helix), all of which were utilized for the current study.
Course Activities
The activities utilized in the course were chosen to highlight specific aspects of NOS
(Table 3). Those familiar with these activities will recognize that each could have been
targeted toward other aspects of NOS as well. However, only those aspects that were
taught in an explicit and reflective way during the course are shown.
Cube activity. The cube activity is a common activity most recently replicated in the
National Academy of Sciences publication Teaching Evolution and the Nature of Science
(1998) and was used as the first NOS activity in this course. In the first portion of the
activity the instructor uses a numbered cube to involve students in asking the question
“what is on the unseen bottom of the cube?” The students then propose an explanation
based on their observations. Then the instructor presents the students with a second cube
and asks them to use the available evidence to propose an explanation for what is on the
bottom of this cube.
While this activity can be used to target a range of NOS understandings, it was explicitly
targeted toward Diversity of Scientific Thinking (“What discoveries in science have
utilized this approach?”, “How does this compare with ‘the’ scientific method?”),
Science & Certainty (“How certain is your hypothesis?”, “Can you be 100% certain of
something you cannot observe yourself?”), Cooperation & Collaboration (“What were
the advantages of working as a group in this activity?”, “Did your partners’ differing
backgrounds influence the process?”), and Analysis & Interpretation of Data (“What
background knowledge did you and your group bring to the activity that allowed you to
come to the hypothesis you did?”, “How does a scientist’s background influence their
interpretation of data?”). The activity and discussion lasted about an hour and a half.
Tricky Tracks. The Tricky Tracks activity is a classic activity in geology education and
has been around for nearly five decades. It was most recently published in Teaching
Evolution and the Nature of Science ([NAS], 1998) as well. In this activity, students
observe and interpret "fossil footprint" evidence. From the evidence, they are asked to
construct defensible hypotheses or explanations for events that took place in the
geological past.
This activity was explicitly targeted toward Diversity of Scientific Thinking (“What
scientific skills were used in forming your hypothesis?”, “How does this compare with
‘the’ scientific method?”), Science & Certainty (“How certain is your hypothesis?”,
“How certain can you be of an event that occurred in the past?”), Cooperation &
Collaboration (“What were the advantages of working as a group in this activity?”, “Do
you think different groups of scientists with differing knowledge backgrounds would
come to the same conclusions with this data?”), and Analysis & Interpretation of Data
(“What background knowledge did you and your group bring to the activity that allowed

5
you to come to the hypothesis you did?”, “How does a scientist’s background influence
their interpretation of data?”). The activity and discussion lasted about forty-five
minutes.
Dino Facts. The Dino Facts activity (Scotchmoor, 1997) is based upon work done by the
paleontologist Jack Horner and other associates of The Museum of the Rockies in
Bozeman, Montana. Data from this research has been used to theorize about the behavior
of dinosaurs in that area. In the activity, groups of students are given envelopes
containing strips of paper, each with an observation made during the field observations in
Montana. The data focuses on the relationship between three Cretaceous-era dinosaur
species. The students are asked to group the data together to make inferences about the
dinosaurs’ behaviors. This process offers a glimpse into paleontological fieldwork.
As above, this activity was explicitly targeted toward Diversity of Scientific Thinking
(“This is not an experimental science. What processes and skills are necessary to do this
work?”, “Is this a good example of ‘the’ scientific method?”), Science & Certainty
(“How certain are your inferences?”, “How certain can you be of an event that occurred
in the past?”), Cooperation & Collaboration (“What were the advantages of working as a
group on this activity?”, “If you could form an expert group to analyze this data, what
specific backgrounds would you look for?”), and Analysis & Interpretation of Data
(“What background knowledge did you and your group bring to the activity that allowed
you to come to the hypothesis you did?”, “How does a scientist’s background influence
their interpretation of data?”). The activity and discussion lasted about an hour and a
half.
The Great Fossil Find. Similar to the Dino Facts activity, the Great Fossil Find (Randak
& Kimmel, 1998) focuses on the process of paleontological fieldwork. Students are
taken on an imaginary fossil hunt. Following a script read by the instructor, students
"find" (remove from envelope) paper "fossils" of some unknown creature, only a few at a
time. Each time, they attempt to reconstruct the creature, and each time their
interpretation tends to change as new pieces are "found.”
Again, this activity was explicitly targeted toward Diversity of Scientific Thinking (“This
is not an experimental science. What processes and skills are necessary to do this
work?”, “Is this a good example of ‘the’ scientific method?”), Science & Certainty (“Did
your inferences change with addition of new data?”, “Will you ever be 100% certain?”),
Cooperation & Collaboration (“Were you more or less effective working as a group in
this activity?”, “If you could form an expert group to analyze this data, what specific
backgrounds would you look for?”), and Analysis & Interpretation of Data (“What
background knowledge did you and your group bring to the activity that allowed you to
come to the hypothesis you did?”, “How does a scientist’s background influence their
interpretation of data?”). The activity and discussion lasted about an hour and a half.
The four activities described above were conducted over a four session unit on teaching
NOS in the secondary science classroom. Taken together, they provided explicit and
reflective NOS instruction on the aspects of Diversity of Scientific Thinking, Science &
Certainty, Cooperation & Collaboration, and Analysis & Interpretation of Data. As
shown in Table 3, they were also reinforced by targeted readings and further discussions.

6
Participants
Seventeen secondary preservice science teachers participated in this study. We report
here findings based upon analysis of data for 14 (10 white females and 4 white males) for
whom complete data sets were obtained. All participants had an undergraduate degree in
science areas, one of them held a master’s degree in entomology, and another had long-
term experience as a chemist in industry. Five participants were selected for summative
interviews for more detailed data on the range of NOS conceptions, reactions to the
course intervention, and patterns of development to represent the rest.
Data Collection and Analysis
The main data collection method was written responses to an open-ended assessment
instrument (Appendix). A total of 12 questions were written to assess 12 aspects of NOS.
Through a pilot test in the previous year, wording of questions were refined to improve
the quality of the responses received. Among the 12 aspects assessed, 10 were from
Osborne et al.’s Delphi study (2003). Two additional assessment items, Use of Models
and Role of Theory, were added to reflect recent discussion in the literature (Justi &
Driel, 2005; Smith & Wenk, 2006). Not all items on the assessment instrument were
explicitly taught during the course. The aspects not taught include Hypothesis &
Prediction, Creativity, Questioning, and Use of Models. These items were used as
controls for the instrument. As would be expected, preservice teachers’ conceptions of
all of these aspects were almost the same throughout the entire study in contrast to the
targeted aspects explicitly addressed in the course. These controlled aspects, therefore,
demonstrated the usefulness of the assessment instrument and coding process for
assessing the learning of preservice teachers.
In both the written and verbal instructions, participants were asked to respond to each of
the items and to provide examples to better illustrate their conceptions. The instrument
was administered twice, once as a pre-assessment before the course and again as a post-
assessment at the conclusion of the course. It took about 45 minutes for the participants
to answer the questions for each administration.
At the end of the study, summative interviews were conducted with five participants.
The summative interview data were used as further data on the role of the course
activities and readings in student learning. Participants were selected for summative
interviews based on their availability.
Both administrations of the instrument were analyzed to create profiles of each
participant. Participants’ responses were coded for each of the 12 aspects of NOS
assessed. Although each assessment item focused on a certain aspect of NOS, we
examined responses across items because the different aspects of NOS were relevant to
some degree and were responded as such by some participants. Individual aspects of
NOS were coded as consistent, partially consistent, or inconsistent with reform
documents. For example, for the Role of Theory aspect, a response of “scientific theories
are both explanatory and predictive in nature and can be modified with the addition of
new evidence” was coded as consistent. The response “scientific theories are
explanations of nature” was coded as partially consistent and “scientific theories are
guesses made by scientists” as inconsistent.

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In order to examine changes in conceptions over the course, coding results from the pre-
and post-assessments were compared. Then, across all participants, a comparison was
made of the overall changes between the pre- and the post-assessment. The percentage of
change was calculated for each aspect of NOS across participants to represent the
percentage of participants (those who were not already at the consistent level) whose
post-assessment responses increased by one or more categories over the course of the
intervention (% Change column in the Table 3).
Results and Discussion
The purpose of this study was to examine the relative efficacy of explicit and reflective
instruction using targeted activities and readings on preservice secondary science
teachers’ conceptions of NOS. In general, the data reveals an overall pattern concerning
the relative degree of change of NOS conceptions over the course intervention and the
number of explicit and reflective activities and readings. More specifically, those aspects
explicitly taught using a combination of activities and readings showed the greatest
change whereas those aspects taught using readings alone were only moderately affected.
Most Developed
The preservice teachers in this study developed their ideas about both the Diversity in
Scientific Thinking and Science & Certainty aspects much more than the other aspects of
NOS (86% and 73% change respectively). The instructional strategy for both aspects
included all four activities and between four and five targeted readings taught using an
explicit and reflective approach. It was likely that through targeted readings and
activities, the preservice teachers had more opportunities to reflect on certain aspects of
NOS resulting in greater learning. In other words, those aspects were emphasized more
than others.
For the Diversity in Scientific Thinking aspect, all participants initially held naïve
conceptions by stating a belief in a universal scientific method. However, those
participants changed their ideas by one or two levels in the post-assessment to explicit
statements denying a universal scientific method. Instead, responses discussed guidelines
and criteria for what makes something scientific.
Among those participants not already at a consistent level concerning Science &
Certainty, 73% also changed their conceptions after the course intervention. Initially they
expressed a belief in the certainty of scientific knowledge, but in the post-assessment,
most acknowledged uncertainty in science in one way or another. When compared to the
pre-assessment, the changes in conceptions of this aspect were three-fold. First, in
accommodating the notion of uncertainty, the majority of participants explicitly
mentioned the durability of scientific knowledge. Second, participants shifted their
explanation of any uncertainty in science from a matter of amount of data on a topic to a
matter of evidence regarding the topic. The third pattern of change in the conception of
uncertainty of science was a shift in the examples used to justify their responses. Many
initially used scientific facts to support their claims of science being certain; later, they
used scientific theories to describe science and certainty.

8
Together, these two aspects of NOS showed a high degree of development over the
course intervention. They were also the only two aspects to include in the instructional
strategy both activities and readings taught using an explicit and reflective approach.
Moderately Developed
In contrast to the aspects of NOS above, 57% and 55% of participants, respectively,
whose initial conceptions were not consistent with the reform documents, developed their
conceptions of Cooperation & Collaboration and Analysis & Interpretation of Data over
the course. The aspect of Cooperation & Collaboration initially revealed a higher degree
of understanding than the other aspects assessed. Half of the participants held a
conception that was consistent with our definition, claiming that science is a collaborative
enterprise in which, although individuals may make significant contributions, scientific
work is often carried out in groups and scientific knowledge claims are generally shared
and must survive a process of critical peer review. Of the remaining half that did not
hold consistent views initially, 57% held more sophisticated views after the course. In
response to the aspect of Analysis & Interpretation of Data, six participants’ conceptions
of the reasons for differing interpretations of data shifted from personal differences and
biases to the theoretical and content backgrounds of the researchers. In other words, they
shifted toward a more theoretically grounded view of science.
The instructional strategy for these two aspects was similar to that of the most developed
aspects. An explicit and reflective approach was utilized with all four activities. Where
the strategy differs, however, is in the number of targeted readings. These two aspects
had two to three targeted readings in contrast to the four to five readings targeted to the
previous aspects.
Least Developed
The final two aspects of NOS were the least developed of the targeted aspects of NOS
over the course. Only 50% of participants’ conceptions of both the Historical
Development of Scientific Thinking and the Role of Theory were affected by the course
intervention. In terms of the Historical Development of Scientific Knowledge, those who
did improve their conceptions had initially expressed either an evolutionary or a
revolutionary view of the Historical Development of Scientific Knowledge. After the
course intervention this developed as they combined the two conceptions into a more
sophisticated view. Participants who initially had difficulty in responding to the Role of
Theory item, more often expressed both the explanatory and predictive nature of
scientific theories on the post-assessment.
The instructional strategy for these two aspects of NOS differed from the others in that no
activities were explicitly targeted towards them. Both aspects, however, did have four
targeted readings which were utilized in an explicit and reflective approach.
Links to Curriculum
In addition to the NOS assessment instruments, we also examined the coursework and
post-instructional interviews (conducted 8 months after the course was completed) for
explicit links between course activities and readings and changes in NOS understandings.
Of the four activities explicitly targeted to aspects of NOS, only two were explicitly

9
mentioned indicating an impact on their understanding. The Tricky Tracks activity was
mentioned by one of the participants in the interview in relation to their response to the
Diversity in Scientific Thinking assessment question. According to this student, the
activity revealed that some scientists “don’t use the scientific method we learned about in
school.” Instead, as the participant expressed in her post-assessment, there are “a lot of
different ways to do science.”
The Cube activity was mentioned by two of the five participants examined. One
participant mentioned in her post-instructional interview that she learned “a lot about the
differences between inferences and observation,” a link to the Analysis & Interpretation
of Data aspect, and that she used the activity in her student teaching. To her, the activity
was “a good way of bringing across the point [about] how you do science.” It helped her
learn about Science & Certainty because she was initially “100% sure of what was on the
bottom,” until hearing other interpretations from the class.
The second participant to explicitly mention the Cube activity first directly referenced it
on his post-assessment response to the Analysis & Interpretation of Data question which
changed from an inconsistent to a partially consistent response: “Each group inferences
different ideas from the same data. Just like the cube activity.” When asked in the post-
instructional interview about relevant activities, the same participant once again
referenced the Cube activity. However, after referencing the Cube activity by name, he
also references, although more indirectly, the Dino Facts and Great Fossil Find activities:
“we did a series of activities where you couldn’t see the end product and had to figure it
out.” He states that these activities helped develop his understandings of the Diversity of
Scientific Thinking and Science & Certainty. Thus, this participant saw a direct link to
these two aspects, and yet referenced the Cube activity explicitly to explain his response
to the Analysis & Interpretation of Data question.
In addition to the activities, one participant specifically mentioned the reading “Words
Scientists Don’t Use” (Ben-Ari, 2005a) in relation to the Science & Certainty aspect of
NOS. Examining the difficulties associated with using words such as ‘prove’ and
‘theory’ in the classroom, the participant explained in his interview that he believes “in
order to get a good grasp of science you really have to know that some things in science
are really well known whereas other things are just being tried out.”
The common mention of class activities after a long period of time indicated that those
activities had an impact on the preservice teachers’ understanding. The participants cited
those activities not just as mere memory of past learning experience but as evidence of
their newly refined conceptions. Moreover, the data indicated potential use of those
activities in actual classroom teaching. This suggested that explicit teaching of NOS had
affected not only preservice teachers’ own understanding of NOS but also their
willingness to utilize their learning experiences in their classroom teaching.
Conclusions and Implications
Research over the past two decades has pointed to the relative efficacy of an explicit and
reflective approach to NOS instruction (Abd-El-Khalick & Akerson, 2004). In addition,
Akerson, Morrison, and McDuffie (2006) found that an activity-based course intervention
was more effective in developing the knowledge of NOS than reflective discussion. Our
study adds to the finding that activities along with targeted reading might be more

10
effective for learning. The current study was designed to determine the relative efficacy
of activities and readings when targeted to specific aspects of NOS and instructed in an
explicit and reflective manner. Cross-referencing the change in the participants’
conceptions of the targeted aspects over the course with the instructional strategy
employed reveals a clear pattern of relative efficacy.
The data reveals an instructional approach consisting of a combination of activities and
targeted readings to be the most effective. Using this approach, two aspects of NOS
(Diversity in Scientific Thinking and Science & Certainty) were highly developed for the
participants over the course. A similar combination, differing only by the number of
targeted readings, led to a reduced effect for two aspects (Cooperation & Collaboration
and Analysis & Interpretation of Data). An instructional approach that consists only of
targeted readings, however, led to less development over the course (Historical
Development of Scientific Knowledge and Role of Theory). Finally, those aspects
included in course discussions and general readings but not targeted for in specific
activities or readings were largely unchanged.
Although our findings show relative efficacies of different teaching approaches in
preference to a combination of targeted reading and activities, it is plausible that general
reading with no specific aspects of NOS targeted had provided a general overview in
which readings and activities for specific aspects were embedded and highlighted. Our
study is limited in informing how general reading and targeted reading and activities
interact each other to produce the learning gained reported in this study. Further research
on organization of readings and activities of different characters will further inform
teacher educators in designing effective courses on NOS.
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Lederman (Eds.), Handbook of research on science teaching and learning (pp.
831-879). London: Lawrence Erlbaum Associates.
Lederman, N. G., & Abd-El-Khalick, F. (1998). Avoiding de-natured science: Activities
that promote understandings of the nature of science. In W. McComas (Ed.), The
nature of science in science education: Rationales and strategies (pp. 83-126).
Dordrecht, The Netherlands: Kluwer.
Lederman, N. G., & Lederman, J. S. (2004). Revising Instruction to Teach Nature of
Science. Science Teacher, 71(9), 4.

12
Lin, H., & Chen, C. C. (2002). Promoting preservice chemistry teachers' understanding
about the nature of science through history. Journal of Research in Science
Teaching, 39(9), 773-792.
National Academy of Sciences [NAS]. (1998). Teaching About Evolution and the Nature
of Science. Washington, D.C.: National Academy Press.
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Washington, D.C.: National Academic Press.
Osborne, J., Collins, S., Ratcliffe, M., Millar, R., & Duschl, R. (2003). What “ideas-
about-science” should be taught in school science? A Delphi study of the expert
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http://www.indiana.edu/~ensiweb/lessons/gr.fs.fd.html.
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about the nature of science. Science Scope, 31(2), 42-47.
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of science in an authentic context: An explicit approach to bridging the gap
between nature of science and scientific inquiry. Science Education, 88(4), 610-
645.
Schwartz, R., & Lederman, N. (2002). "It's the Nature of the Beast": The Influence of
Knowledge and Intentions on Learning and Teaching Nature of Science. Journal
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Wivagg, D., & Allchin, D. (2002). The Dogma of "The Scientific Method". American
Biology Teacher, 64, 645-646.

13
Table 1
Descriptions of NOS Themes
NOS Theme Description
Science & Certainty
(Assessment item 1)
Much of scientific knowledge is well established and beyond
reasonable doubt, while other scientific knowledge is more
open to legitimate doubt. Current scientific knowledge is the
best we have but may be subject to change in the future given
new evidence or new interpretations of old evidence.
Analysis &
Interpretation of Data
(Assessment item 2)

The practice of science involves skilful analysis and
interpretation of data. Scientific knowledge claims do not
emerge simply from the data but through a process of
interpretation and theory building that can require sophisticated
skills. It is possible for scientists legitimately to come to
different interpretations of the same data, and therefore to
disagree. Interpretations are based on the scientists’ current
paradigm.
Scientific Method &
Critical Testing
(Assessment item 3)
Science uses the experimental method to test ideas that include
basic techniques and the use of controls in particular. The
outcome of a single experiment is rarely sufficient to establish
a knowledge claim.
Hypothesis &
Prediction
(Assessment item 4)
Scientists make a hypothesis either from their observations or
their theories. Once confirmed, theories allow predictions.
Creativity in Science
(Assessment item 5)
Creativity is a vital, yet personal, ingredient in all aspects of
science.
Science & Questioning
(Assessment item 6)
An important aspect of the work of a scientist is the continual
and cyclical process of asking questions and seeking answers,
which then lead to new questions. This process leads to the
emergence of new scientific theories and techniques, which are
then tested.
Cooperation &
Collaboration
(Assessment item 7)
Science is a communal activity. Although individuals may
make significant contributions, scientific work is often carried
out in groups, frequently of a multidisciplinary and
international nature. New knowledge claims are generally
shared and, to be accepted by the community, must survive a
process of critical peer review.
Science and
Technology
(Assessment item 8)
Although there is a distinction between science and technology,
the two are increasingly interdependent as new scientific
discoveries are reliant on new technology and new science
enables new technology.
Historical
Development of
Scientific Knowledge
The history of science reveals both evolutionary and
revolutionary changes. With new evidence and interpretation,
old ideas are replaced or supplemented by newer ones.

14
(Assessment item 9)
Diversity in Scientific
Thinking (Assessment
item 10)
Science uses a range of methods and approaches and there is no
one scientific method or approach. Different fields of science
require different methods as they ask different types of
questions.
Role of Models *
(Assessment item 11)
Scientists use models in order to explain, predict, and represent
phenomena of their research. Models are not always exact
representations of nature. Various models are used including
scale models and mental models.
Role of Theory *
(Assessment item 12)
A scientific theory is a concise and coherent set of concepts,
claims, and laws that can be used to explain and predict natural
phenomena. They provide a framework for research and are
sometimes modified scientists try to make them coherent with
new evidence.
Adapted from Osborne et al. (2003).
*Denotes aspects of NOS not included in Osborne et al. (2003) but included in this study.

15
Table 2
Course Readings
General NOS readings:
• American Association for the Advancement of Science [AAAS]. (1990). Science
for all Americans. New York: Oxford University Press.
• National Academy of Sciences. (1998). Teaching About Evolution and the Nature
of Science. Washington, D.C.: National Academy Press.
Targeted NOS readings
• Farber, P. (2003). Teaching Evolution & the Nature of Science. American Biology
Teacher, 65, 347-354.
• Hagen, J. B., Allchin, D., & Singer, F. (1996). Lynn Margulis: The question of
how cells evolved. In Doing biology. New York, NY: HarperCollins College
Publishers.
• Schwartz, R. (2007). What's in a word?: How word choice can develop
(mis)conceptions about the nature of science. Science Scope, 31(2), 42-47.
• Wivagg, D., & Allchin, D. (2002). The Dogma of "The Scientific Method".
American Biology Teacher, 64, 645-646.
• Ben-Ari, M. (2005a). Words scientists don't use. In Just a Theory: Exploring the
Nature of Science (pp. 45-61). Prometheus Books.
• Ben-Ari, M. (2005b). Just a theory: What scientists do. In Just a Theory:
Exploring the Nature of Science (pp. 23-43). Prometheus Books.
• Ben-Ari, M. (2005c). Falsificationism: If it might be wrong, it’s science. In Just a
Theory: Exploring the Nature of Science (pp. 63-78). Prometheus Books.

16
Table 3
Changes in Understandings of NOS Aspects Based on Activities and Readings
Aspect of NOS Activities Readings
% Change
(Pre/Post)*
Diversity in
Scientific
Thinking
The Great Fossil Find
Dino Facts
Tricky Tracks
Cube activity
• ([NAS], 1998)
• (Farber, 2003)
• (Hagen, Allchin, & Singer, 1996)
• (Wivagg & Allchin, 2002)
86%
Science &
Certainty
The Great Fossil Find
Dino Facts
Tricky Tracks
Cube activity
• ([NAS], 1998)
• (Ben-Ari, 2005a, 2005b, 2005c)
• (Farber, 2003)
• (Hagen, Allchin, & Singer, 1996)
• (Schwartz, 2007)
73%
Cooperation &
Collaboration
The Great Fossil Find
Dino Facts
Tricky tracks
Cube activity
• ([NAS], 1998)
• (Ben-Ari, 2005c)
• (Hagen, Allchin, & Singer, 1996)
57%
Analysis &
Interpretation
of Data
The Great Fossil Find
Dino Facts
Tricky Tracks
Cube activity
• ([NAS], 1998)
• (Hagen, Allchin, & Singer, 1996) 55%
Historical
Development of
Scientific
Knowledge
• ([NAS], 1998)
• (Ben-Ari, 2005c)
• (Farber, 2003)
• (Hagen, Allchin, & Singer, 1996)
50%
Role of Theory
• ([NAS], 1998)
• (Ben-Ari, 2005a, 2005b)
• (Farber, 2003)
• (Hagen, Allchin, & Singer, 1996)
50%
Science &
Technology

44%
Scientific
Method &
Critical Testing

36%
Science &
Questioning

36%
Creativity 29%
Role of Models 29%
Hypothesis &
Prediction

7%
*Percentage whose post-assessment response increased by one or more categories after
the course and were not already at the consistent level before the course.

17
Appendix
Assessment Questions*

1. How certain is scientific knowledge? Is there a range of certainty? If so, provide
examples.
2. It is believed that about 65 million years ago the dinosaurs became extinct. Of the
hypotheses formulated by scientists to explain the extinction, two enjoy wide
support. The first, formulated by one group of scientists, suggests that a huge
meteorite hit the earth 65 million years ago and led to a series of events that
caused the extinction. The second hypothesis, formulated by another group of
scientists, suggests that massive and violent volcanic eruptions were responsible
for the extinction. How are these different conclusions possible if scientists in
both groups have access to and use the same set of data to derive their
conclusions?
3. What is an experiment? Does the development of scientific knowledge require
experiments? Why or why not?
4. What role do predictions and hypotheses play in developing scientific
explanations?
5. Is creativity an important aspect of science? If so, how? Can you provide an
example?
6. How does questioning fit into the scientific process?
7. Does new scientific knowledge in science (i.e. relativity, plate tectonics) stem
from individuals or the community of scientists as a whole? How?
8. Do technology and science affect each other? If so, how?
9. How has science progressed historically? What happens to the old ideas when
new ones come to light?
10. Is there a universal scientific method? If yes, then what is it? If no, then what, if
any, rules govern what is “scientific”?
11. What is a model in science? Provide an example. For what purposes do scientists
use models?
12. What are scientific theories? What role do they play in the scientific process?
*Selected only those relevant to the current report