J Sci Teacher Educ
DOI 10.1007/s10972-013-9373-9
ELEMENTARY SCIENCE TEACHER EDUCATION
Promoting the Understanding of Photosynthesis
Among Elementary School Student Teachers Through
Text Design
Ilona Södervik • Mirjamaija Mikkilä-Erdmann
Henna Vilppu
•
The Association for Science Teacher Education, USA 2013
Abstract The purpose of this study was to investigate elementary school preservice teachers’ understanding of photosynthesis and to examine if a refutational
text can support understanding of photosynthesis better than a non-refutational text.
A total of 91 elementary school pre-service teachers read either a refutational or a
non-refutational text concerning photosynthesis and then answered open-ended
questions. Our results indicate that there are critical problems associated with student teachers learning about the process of photosynthesis, even after it has been
systematically taught in teacher education. However, the results positively indicate
that refutational science texts seem to foster effective conceptual change among
student teachers. The results interestingly showed that students who read a refutational text improved their systemic and factual understanding of photosynthesis
more than did those who read a non-refutational text. Especially students who had
naı̈ve prior understanding regarding photosynthesis benefitted more from a refutational text. Thus, a refutational text may act as an effective facilitator of conceptual
change. These results have implications for teacher education, where conceptual
mastery of the most important science phenomena, such as photosynthesis, should
be achieved. A refutational text is an easy and effective way to support conceptual
change in higher education. Thus, this study highlights the importance of domainspecific science education in teacher programmes.
Keywords Systemic understanding Refutational text Photosynthesis Conceptual change Science learning Higher education
Prof. Mikkilä-Erdmann leads the LeMed project, 128892, financed by the Academy of Finland.
I. Södervik (&) M. Mikkilä-Erdmann H. Vilppu
Department of Teacher Education, Centre for Learning Research, University of Turku,
Assistentinkatu 5, 20014 Turku, Finland
e-mail: [email protected]
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Introduction
The Role of Textbooks in the Understanding of Complex Concepts
in the Science Classroom
In most countries, elementary school teachers are responsible for teaching the science
curriculum to children during their first 6 years of schooling. This is also the case in
Finland where this study was conducted. Teachers are key players in shaping the minds
of future decision-makers. Previous studies have shown that teachers teach in
accordance with their own understanding, whether this is right or wrong, and students’
conceptions mirror their teachers’ ideas (Tullberg, Strödahl, & Lybeck, 1994).
Previous studies have found that student teachers in Finland, as in several other
countries, have problems understanding, for example, the process of photosynthesis
(Ahopelto, Mikkilä-Erdmann, Anto, & Penttinen, 2011; Mintzes & Wandersee, 2005;
Ross, Tronson, & Ritchie, 2005). The question then arises as to how elementary school
teachers can support children’s science understanding if the teachers themselves have
a poor understanding of the most important biological process—photosynthesis?
The most important instrument for teachers in a science classroom seems to be the
textbook, as a great part of the learning required in the school context occurs through
successful text reading (Mikkilä-Erdmann, 2002; Mason, Gava, & Boldrin, 2008).
Finnish elementary school teachers, for example, have an enormous challenge in
mastering the content knowledge, as well as the pedagogical content knowledge, of
approximately 12 subjects taught at the primary level (see, e.g., Käpylä, Heikkinen, &
Asunta, 2009). Hence, it is understandable that textbooks dominate science instruction
in schools (Mikkilä-Erdmann, 2002; Hynd, 2001; Mason et al., 2008). However,
previous studies have shown several problems in textbooks such as sentences that are
too short or are incoherent and which thus do not support the construction of a systemic
understanding or detaching figures that cannot be exploited in learning (see, e.g.,
Mikkilä & Olkinuora, 1995; Chambliss & Calfee, 1998). Another problem with many
textbooks is that they usually present scientific models and concepts as if learners have
no prior knowledge or have only relevant prior knowledge about the topic to be learned
(Mikkilä-Erdmann, 2002). Further, biological processes are often reduced as separate
facts in the school curriculum (see Barak, Sheva, & Gorodetsky, 1999), or are
practised in laboratory settings without a proper understanding of what students should
be learning. As a result of these practices in the teaching of science, neither teachers
nor their students are able to situate and use science knowledge effectively and
creatively outside the classroom.
A common notion about text comprehension is that a reader constructs mental
representations during text processing (Mikkilä-Erdmann, Penttinen, Anto, &
Olkinuora, 2008). According to Kintsch (1988), two types of representations are
constructed—the text base and the situational model. The first is constructed from the
semantic content of the text, whereas the latter refers to the mental representation that
the reader constructs of the whole while he or she reads the text (see Kintsch, 1986).
Both levels are needed depending on the situation in which knowledge is used—the
text base level enables the learning of facts from the text, whereas at the situational
model level, the text itself disappears and its content is situated in a larger context.
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Promoting the Understanding of Photosynthesis
The learning of multifaceted science phenomena such as photosynthesis requires
constructing a situational model from the text, which makes it possible to solve
different kinds of problems in varying situations. Understanding abstract and
complex scientific phenomena requires knowing many facts as well as being able to
construct an elastic, flexible, simulation-like representation of the whole system (see
also Brown & Schwartz, 2009; Kinchin, 2000a). The notion of a ‘systemic idea’
means that understanding a phenomenon involves having a working mental
representation of it (for mental representations, see, e.g., Johnson-Laird, 1983). One
has to know how separate concepts and facts together construct a complex network
in which the concepts are interconnected and interrelated (see Barak et al., 1999;
Mayr, 1997). Systemic understanding is a prerequisite for understanding the
complex, interconnected processes of the Earth’s ecosystem that influence each
human being’s everyday life. This can be seen as a challenge for developing science
textbooks and science teaching in schools on the whole.
Previous Misconceptions as a Challenge for Conceptual Change
Previous knowledge and, more importantly, its quality, influences the learning of a
certain topic (see Ausubel, 1968). Previous knowledge may promote learning when
in unison with new information, or it may hinder learning if there are discrepancies
between the old and new information (for a review, see diSessa, 2006). Although
misconceptions exist in almost every subject area, they seem to be especially
prevalent in science, for most people have those (Maria, 2000; Tippett, 2010).
Certain robust misconceptions of basic science phenomena develop at a young age
and are constantly reconfirmed by everyday experiences in lay culture (Vosniadou,
Vamvakoussi, & Skopeliti, 2008).
Inaccurate previous knowledge is particularly problematic when trying to
understand phenomena such as photosynthesis. The intangibility of the process
partially explains why researchers have found the same type of misconceptions
concerning photosynthesis among children and adults, such as water for plants being
viewed as the same as food for animals (see, e.g., Duit & Treagust, 2003; Mintzes &
Wandersee, 2005; Roth, 1990). For example, many of us have experiences of
growing a plant and we know what happens if we forget to water it. However, we
cannot actually see the process of photosynthesis and, hence, we may wrongly think
of the water the plant needs to survive as being like the food we need to live. Hence,
understanding complex scientific phenomena such as photosynthesis usually
requires rearranging previous everyday knowledge structures and even abandoning
certain previous misconceptions, that is, conceptual changes (Duit, 1999; Posner,
Strike, Hewson, & Gertzog, 1982; Vosniadou, 1994).
Conceptual change can be perceived as a complex process in which an individual
reorganises existing knowledge structures (Limón & Mason, 2002; Posner et al.,
1982). It is not merely replacing previous, incorrect conceptions with new ones but
rather opening up new conceptual space (Duit, 2009). Thus, conceptual change
includes abandoning and revising certain previously held conceptions and realising
interconnections and links between concepts one may have not even thought of
earlier. Conceptual change is usually extremely difficult to achieve, because
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everyday conceptions are often so robust that abandoning them and acquiring a new
perspective is not simple. Achieving conceptual change usually requires one to be
aware of the discrepancy between one’s conceptions and the scientific idea and be
willing to change one’s conceptions to align them better with the science (Chinn &
Brewer, 1993; Duit, 1999; Posner et al., 1982; Vosniadou, 1994). That is why
systematic learning and teaching are often prerequisites for conceptual change (see
Duit, 1999; Sinatra & Mason, 2008).
Refutational Text as a Facilitator of Conceptual Change
As justified earlier, a text that does not take into consideration readers’
preconceptions often cannot support deep learning, and, typically, students learn
solely to reproduce the text instead of to achieve conceptual change (van Dijk &
Kintsch, 1983; Kintsch, 1986). A refutational text is a particular type of text design
that aims to support the reader’s meta-conceptual awareness, i.e., awareness of
one’s existing conceptions so as to promote conceptual change. A refutational text
systematically points out the differences between a student’s thinking and scientific
notions and thus assists the learner in revising his or her mental model (Hynd,
2001). It usually includes three elements: a typical misconception of a certain
concept, a refutation and then the correct explanation (Hynd, 2001).
Refutational text studies have presented several examples of effective refutational texts that have helped facilitate conceptual change with respect to a variety of
science topics, although there are also contradictions (see, e.g., Alvermann & Hynd,
1989; Mikkilä-Erdmann, 2001; Broughton, Sinatra, & Reynolds, 2010; Diakidoy,
Mouskounti, & Ioannides, 2011; Guzzetti, Williams, Skeels, & Wu, 1997). Hence,
refutational texts that challenge the reader to question his/her previous conceptions
are a promising instrument for science educators. Previous studies have also
indicated that refutational texts especially support situational model level learning,
i.e., systemic understanding, whereas facts can easily be learnt from refutational and
non-refutational texts (see, e.g., Mikkilä-Erdmann, Penttinen, Anto, & Olkinuora,
2008; Penttinen, Anto & Mikkilä-Erdmann, 2012; Diakidoy et al., 2011).
Learning researchers have published several articles about different kinds of
interventions that have successfully promoted conceptual change (Guzzetti,
Snyder, Glass, & Gamas, 1993; Pfundt & Duit, 1991; Tippett, 2010). However,
conceptual change has typically been measured using, for example, different types
of multiple-choice questionnaires that have been scored and used as an indication
of learning. In-depth analyses of conceptual change concerning for example the
understanding of photosynthesis is however missing. In sum, this article aims to
establish whether elementary school teachers’ factual and systemic understanding
of photosynthesis is supported by either a non-refutational or a refutational text.
Unlike previous studies, our approach is domain specific. In other words, our aim
is to study what makes photosynthesis such a difficult concept to understand even
for university students. In addition, we aim to contribute to the larger discussion
of science learning and domain-specific university pedagogy of biology in teacher
education.
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Promoting the Understanding of Photosynthesis
Research Questions
To examine what kind of conceptual understanding pre-service elementary school
teachers have concerning photosynthesis, our first research question is:
1.
How do pre-service elementary school teachers perform on a pre-, post- and
delayed post-test that measure the systemic and factual understanding of
photosynthesis?
To gain a more profound insight into how participants’ understanding changed
after reading the text, we ask:
2.
How does students’ systemic and factual understanding of photosynthesis
change after reading either a refutational or a non-refutational text?
Finally, we ask:
3.
Does the level of prior knowledge affect students’ learning when using a
refutational as opposed to a non-refutational text?
Method
Participants
Ninety-one native Finnish-speaking second-year student teachers from a Finnish
university participated in the study. A total of 71 (78 %) students were female, and
20 (22 %) were male. The average age of the students was 24 (M = 24, SD = 5.9).
Approximately three out of every four students (N = 66, 72.5 %) had completed a
compulsory basic course on biology for the elementary school level. These studies
consist of four credits in biology and health education, which cover the study of
photosynthesis. The students were randomly assigned to different text groups, where
half of the students (N = 45) read a refutational science text on photosynthesis, and
the other half (N = 46) read a non-refutational text about the same phenomenon.
Design and Materials
The study was based on a pre- and post-test design and was conducted during two
compulsory sessions of 90 min each (see Table 1).1 Participation in the study itself
was voluntary. Pre- and post-tests and the text intervention were administered
during the first session, and a delayed post-test and feedback about the design and
the students’ performance in the first session were given 2 weeks later in the second
session. In the pre-test, post-test and delayed post-test, the students were asked to
answer eight open-ended questions concerning photosynthesis (the authors can
provide the translated questions on request). These included factual questions such
1
The researchers were present at the data-collection sessions. However, they were not involved in the
instructions given in the course.
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Table 1 Research design and materials
Session 1
Session 2
Pre-test
Intervention
Post-test
Delayed post-test and
feedback
Background
information
A refutational science text
on photosynthesis
Open-ended questions
about photosynthesis
Open-ended questions
about photosynthesis
An orienting mind
map of
photosynthesis
OR
Open-ended questions
about photosynthesis
A non-refutational
science text on
photosynthesis
Feedback on the design
and preliminary results
as, ‘What functions do stomata have in a plant?’ and generative questions like,
‘What kind of role does a plant play in the food chain?’
In the pre-test, students submitted written answers to questions about background
information as well as open-ended questions. After answering the pre-test questions,
half of the students (N = 45) read a refutational science text on photosynthesis,
whereas the other half (N = 46) read a non-refutational text about the same
phenomenon. The texts focused on the nourishment supply of plants, the selfsufficiency of photosynthesising organisms, the flow of energy in the food chain and
the significance of photosynthesis to life on Earth. The texts were in Finnish, and
they were identical apart from two additional refuting paragraphs in the middle of
the refutational text.
The two refutational paragraphs pointed out typical misconceptions concerning
photosynthesis and discussed concepts in pairs such as energy versus matter,
nutrients versus nourishment and plants versus animals. These concepts were
chosen based on previous literature showing that they are often misunderstood by
children and adults (see, e.g., Mikkilä-Erdmann, 2002; Kinchin, 2000b; Mintzes &
Wandersee, 2005; Roth, 1990; Vosniadou et al., 2008). Because of the two extra
paragraphs, the refutational text was slightly longer (584 vs. 490 words). A
translated section from the texts is presented in ‘‘Appendix’’.
After reading the science texts, the two groups of students answered the same
open-ended questions without the text, although they were allowed to see their pretest answers. Thus, the students could just write ‘the same’ if they did not want to
add anything to their answers or ‘the same ? …’, including any additional
information they had learnt from the text. The students had 90 min to complete the
pre- and post-tests as well as read the short text. They moved at their own pace, and
every participant finished the tasks before the deadline.
A delayed post-test with a feedback session was administered 2 weeks later when
the same students were still available to participate in the second phase of the study.
The students were asked to answer the same open-ended questions concerning
photosynthesis, once again at their own pace. After everyone had finished the task,
the participants were given feedback about the design and their performance in the
intervention. Typical misconceptions were brought up and corrected in order to
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make sure that participants were not left uncertain about the scientific model of
photosynthesis.
Data Analysis
The pre-, post- and delayed post-test data were analysed qualitatively and
quantitatively. First, a conceptual map connecting 12 central concepts of
photosynthesis was constructed, based on the current scientific understanding of
photosynthesis2 (see Fig. 1). The map highlights the main points of the phenomenon
such as raw materials, energy source and the end products of photosynthesis and
explains how photosynthesis is linked to the supply of nourishment for all
organisms on Earth. This conceptual map was used as an analysis tool. Based on the
open-ended questions, the participants’ pre-, post- and delayed post-test answers
were first visualised by the researchers using the conceptual map (see Fig. 1).
The idea was to understand what kind of representation each participant had
concerning photosynthesis before and after the text reading by adding different
coloured links between the concepts on the map based on the written answers. Each
visualisation link was scored (correct conception, green link, ?2 points; simplified,
not a false conception, yellow link, ?1 point; missing link, 0 points; misconception,
red link, -2 points). The maximum score was 24, but the score could also be below
zero. Four links were categorised as systemic and having a green link to these items
suggested a high-level systemic understanding of the concept. Eight links were
categorised as factual, because they suggested an important but lower-level factual
understanding of photosynthesis. The criteria for the final analysis were created by
the first author, a biologist. Two researchers analysed 20 % of the data
independently. The inter-rater reliability of the analysis was 81 %, which was
considered high in this qualitative, in-depth type of analysis. The idea for this map
was adapted for the purpose of an effective analysis tool that would reveal if the
participants had a correct understanding of the essential concepts about photosynthesis and their interconnections. Additionally, this analysis method also made it
possible to see, firstly, what kind of representation each participant had constructed
of the whole system and, secondly, to detect in which part of the system the possible
misconceptions and deficiencies had occurred.
Participants’ pre-test representations were categorised as scientific, moderate or
naı̈ve based on their understanding of the most critical link between ‘photosynthesis’ and ‘nourishment’. This link is critical in understanding photosynthesis, so if
this connection was understood (marked with a green link), it meant the participant
most likely had a thorough previous understanding of the meaning of photosynthesis
on a global level. A yellow link between the concepts in question indicated a
moderate understanding, because whether the participant had deeply understood the
connection or not remained unclear (e.g., if there were contradictions in the
answers). If the connection was not mentioned at all (missing link) or there was a
2
The analysis tool was constructed by the first author, a biologist.
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I. Södervik et al.
1. Energy for photosynthesis comes from sunlight.
2. H2O is a raw material for photosynthesis.
3. CO2 is a raw material for photosynthesis.
4. O2 is an end product of photosynthesis.
2.
1.
5. Sugar is an end product of photosynthesis.
4.
6. Photosynthesis is the origin of nourishment needed
by living organisms.
6.
5.
3.
7. Nutrients are elements that plants need for their
development and get from the soil. Nutrients are not
7.
8.
a synonym for nourishment, because nutrients are
only one small part of nourishment and do not bring
9.
energy for the organism.
8. Animals are heterotrophic and thus depend on other
organisms.
10.
11.
9. Plants are autotrophic and produce their nourishment
by themselves.
10. Animals are the consumers of the food chain.
12.
11. Plants are the producers of the food chain
12. Each step in the food chain uses energy for its own
vital functions, etc., and thus only a small amount of
all the energy received from the nourishment is used
for the organism’s growth.
Fig. 1 Conceptual map of photosynthesis used as an analysis tool
misunderstanding concerning these concepts (red link), the representation was
interpreted as naı̈ve. The overall performance scores of these categories were
compared before and after the participants read the text in different text-type groups
using a repeated measures ANOVA. Changes in participants’ scores on different
measurement points were analysed using a repeated measures ANOVA in order to
understand if the text generally supported learning and if there were changes in their
level of understanding 2 weeks after the intervention. A repeated measures ANOVA
with text as the ‘between subjects’ factor was administered to compare the
performance of the participants in the text-type groups. In the ANOVA, we
exploited a repeated contrast comparison in order to compare results between
different measurement points and used Greenhouse–Geisser correction to the
degrees of freedom.
Lastly, each link was examined separately in the pre-test and post-test between
the text-type groups. Increasing percentages were calculated for each link to find
out which conceptions had changed the most after reading the text and to compare
further the changes between the refutational and non-refutational text groups.
Increasing percentages were calculated so that all students’ scores per link (green
link, ?2 points; yellow link, ?1 point; missing link, 0 points; red link, -2 points)
were summed up and compared with the text-type groups in the pre- and posttests. We illustrate the results via qualitative citations of certain representative
cases.
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Promoting the Understanding of Photosynthesis
Table 2 Students’ scores on the pre-test, post-test and delayed post-test (max. score 24)
N
M
SD
Min
Max
Pre-test
91
9.82
7.05
7.05
24.00
Post-test
91
16.20
5.26
1.00
24.00
Delayed post-test
87
15.54
5.17
3.00
24.00
Results
Learning Results Concerning Photosynthesis in the Conceptual Change Test
We analysed participants’ conceptual understanding of photosynthesis before and
after reading the text. On the pre-test, the participants’ average score was 10 out of
24 (M = 9.84, SD = 7.05; see Table 2). The average score for links concerning
factual understanding was 7.1 out of 16 (44 %), whereas the average score for links
concerning systemic understanding was 3.3 out of 8 (41 %). Hence, the student
teachers’ understanding was worryingly poor before they read the text, although
most had completed a basic course on biology for the elementary school level. For
this reason, a higher degree of understanding had been expected.
On the post-test, the students’ average score was 16 out of 24 (M = 16.20,
SD = 5.26). The average score for links concerning factual understanding was 11.2
out of 16 (70 %), whereas the average score for links concerning systemic
understanding was 5.3 out of 8 (66 %). Between the pre-test and post-test, the scores
changed highly significantly [F(1, 86) = 113.78, p \ 0.001]. Overall, the text
supported learning effectively. The participants’ average score remained rather high
also on the delayed post-test at 16 out of 24 (M = 15.54, SD = 5.17). However, the
reducing of the scores is significant between the post-test and the delayed post-test
[F(1, 86) = 5.05, p = 0.027].
How Does a Refutational Text Compared to a Non-refutational Text Foster
Students’ Learning?
First, we ensured that our treatment groups were comparable by analysing the
groups’ pre-test scores with an independent samples t test. The level of previous
knowledge of photosynthesis did not differ significantly between the text-type
groups, which indicates that the groups were comparable [t(89) = 0.71, p [ 0.05;
see Table 3].
We then examined how the students’ performance scores in different text-type
groups changed between the pre- and post-tests. When we compared learning in
different text type groups, we found that there was no significant interaction effect
between different text types and measurement times [F(1, 120) = 2.80, p = 0.08].
However, a repeated contrast comparison revealed that the difference in scores
between the pre-test and post-test was statistically significant [F(1, 85) = 4.39,
p = 0.039], but not between the post-test and delayed post-test [F(1, 85) = 1.02,
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Table 3 Students’ scores on the pre-test, post-test, and delayed post-test in different text-type groups
(max score 24)
N
NT
M
RT
NT
SD
RT
NT
Min
Max
RT
NT
RT
NT
RT
Pre-test
46
45
10.35
9.29
6.95
7.19
-2.00
-2.00
23.00
24.00
Post-test
46
45
15.43
16.98
5.68
4.73
1.00
7.00
24.00
24.00
Delayed post-test
45
42
15.33
15.76
5.28
5.10
3.00
5.00
24.00
24.00
NT non-refutational text group, RT refutational text group
Fig. 2 Changes in the performance scores between the pre-, post- and delayed post-tests in different texttype groups
p = 0.314] (see Fig. 2). Thus, a refutational text seemed to support learning more
than a traditional, non-refutational text. Further, both groups’ scores declined
equally slightly between the post-test and delayed post-test.
We further examined those who had a naı̈ve representation before reading the
text regarding the connection between the concepts of ‘photosynthesis’ and
‘nourishment’ (non-refutational text group, n = 21; refutational text group, n = 26)
and compared how their scores had improved after reading. As Fig. 3 shows,
participants with previously naı̈ve conceptions who had read a refutational text
improved their scores significantly more than those who had read the nonrefutational text [F(1, 45) = 3.93, p = 0.05, g2 = 0.08]. In the groups with
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Promoting the Understanding of Photosynthesis
Fig. 3 The improvement in students’ scores with a naı̈ve model on the pre-test in different text-type
groups
moderate or high previous knowledge, there was no statistical or indicative
difference in learning results between the text-type groups. Instead, if one had a
moderate or scientific representation before reading the text, the text types seemed
to work similarly.
In-depth Qualitative Analysis of Conceptions of Photosynthesis
We were also interested in how participants’ general understanding of a conceptual
map and knowledge of connections between the concepts of photosynthesis
improved after reading the text. We investigated participants’ understanding of
photosynthesis more closely by calculating from the analysed representations how
the scores of each link changed after reading the text. The improvement percentages
for each link are presented in Table 4 in order of the degree of improvement.
As stated earlier and as can be seen in Table 4, the refutational text fostered
learning more than the non-refutational text. The students who read the refutational
text instead of the non-refutational text improved their understanding more
concerning nine links, whereas the non-refutational text group increased their scores
in only three links.
Links 6, 10, 12 and 11 (highlighted in italics in Table 4) handled the
phenomenon from the systemic point of view, and Table 4 shows that performance
scores concerning these links improved more in the refutational text group. For
123
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Animals are heterotrophic and thus depend on other organisms
Animals are the consumers of the food chain
Energy for photosynthesis comes from sunlight
Plants are autotrophic and produce their nourishment by themselves
Each step in the food chain uses energy for its own vital functions, etc., and thus only a small
amount of all the energy received from the nourishment is used for the organism’s growth
Plants are the producers of the food chain
H2O is a raw material for photosynthesis
Sugar is an end product of photosynthesis
CO2 is a raw material for photosynthesis
O2 is an end product of photosynthesis
8.
10.
1.
9.
12.
11.
2.
5.
3.
4.
See Fig. 1
Nutrients are elements that plants need for their development and get from the soil. Nutrients
are not a synonym for nourishment, because nutrients are only one small part of nourishment
and do not bring energy for the organism
a
90
Photosynthesis is the origin of nourishment needed by living organisms
6.
7.
8
28
48
50
43
56
95
100
40
136
200
Non-refutational
text improvement %
Scientific explanations of the links in the analysis tool
Link numbera
Table 4 Improvement percentages in the performance scores in different text-type groups between the tests (N = 91)
11
29
52
74
79
86
70
117
119
127
120
450
Refutational text
improvement %
I. Södervik et al.
Promoting the Understanding of Photosynthesis
example, the refutational text seemed to support a substantial understanding of
photosynthesis from the systemic point of view, according to which it is essential to
understand that photosynthesis is the origin of nourishment, although none of the
refuting paragraphs directly focused on this concept (link number 6). On the pretest, the question, ‘You get energy when you eat a potato. How did the energy end
up in the potato?’, was answered incorrectly as follows by a participant who had
read a refutational text: ‘A potato got the energy from the soil via its roots’. On the
post-test, her answer to the same question was scientifically correct, although
slightly narrow: ‘The potato plant photosynthesised and stored the extra energy in
the potato tuber that we can eat’. The student’s other answers revealed that she had
achieved a conceptual change concerning photosynthesis.
Another example is from a student who had read the non-refutational text and did
not understand the connection between ‘photosynthesis’ and ‘nourishment’. To the
question, ‘What is photosynthesis?’, this student answered on the pre-test:
‘Photosynthesis is ‘‘breathing’’ of the plant. The plant takes carbon dioxide from
the air and releases oxygen, which can be called ‘‘breathing’’. In this process, there
is also generated something else, might it have been glycose (sic) or some plant
sugar.’ This student did not change his answer on the post-test, and thus did not
achieve any conceptual change. Those who read the refutational text seemed to have
also learnt better the essential notion that animals are consumers of the food chain
(link 10) and thus depend on the chemical energy that green plants produce.
In contrast to the previously presented results, the participants who read the nonrefutational text improved their understanding more than those who read the
refutational text regarding ‘nutrients’ and ‘nourishment’ (link 7). This result was
somewhat surprising, because in the refutational text a paragraph emphasised that
nutrients and nourishment are not synonyms, but the first can be included in the
latter. However, it is slightly arguable, at least in this study, whether learning about
nutrients required systemic or factual learning, because it depended on the quality of
the answer if the concept was used as a factual detail or if it was applied as
effectively. One participant who had read the refutational text answered incorrectly
on the pre-test question, ‘How does a dandelion get its energy?’: ‘A dandelion gets
its energy from the water and nutrients that it gets from the soil via the roots. In the
process of cell respiration, these substances are changed to the energy’. Furthermore, when asked how energy ends up in lettuce, she answered again incorrectly
that lettuce does not contain energy because it is a plant. She did not change her
answers on the post-test, which indicates that the refutational text did not manage to
help this student understand concepts of nutrients, nourishment, energy and the
relations between them. Another participant who had read the non-refutational text
gave the following answer on the pre-test to the question, ‘How does a dandelion get
its nourishment?’: ‘A dandelion gets its nourishment from the soil’. On the post-test,
she gave a more scientific response: ‘A dandelion produces its nourishment by itself
via photosynthesis’.
Generally, those links that clearly indicated a systemic understanding (highlighted in italics in Table 4) were better understood by the refutational text group.
Of particular note was that the understanding of ‘nourishment’ and its connection to
‘photosynthesis’ was five times better in the refutational text group. However, the
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refutational text group also better understood factual links, such as links 1–5
concerning the end products and raw materials of photosynthesis. Overall, those
who read the refutational text had an improved understanding in nine out of 12
links. However, the non-refutational text group learnt certain concepts better. For
example, the non-refutational text group better understood the concept of a
‘nutrient’ and its relation to ‘nourishment’. In addition, autotrophy and heterotrophy, which presumably indicated mainly factual learning, were better learnt by the
non-refutational text group.
To sum up, our results indicate that there are critical problems associated with
student teachers learning about the process of photosynthesis, even after it has been
systematically taught in teacher education. There was also a lot of variation among
students. However, it seems that a refutational text may act as an effective facilitator
of conceptual change, especially for those whose previous understanding was poor.
The refutational text supported participants especially well in understanding the
connection of photosynthesis to the production of nourishment by organisms.
Discussion
This study aimed to contribute to the discussion of domain-specific university
pedagogy of biology in teacher education. Thus, the purpose of this study was to
investigate what kind of conceptions elementary school student teachers have
regarding photosynthesis and whether or not a refutational text fosters an
understanding of the phenomenon more effectively than a traditional, nonrefutational text. We were also interested in how the level of learners’ previous
knowledge was connected to learning via different text types. In-depth analysis
enabled us to determine how systemic and factual understanding developed during
the experiment. Based on this, we make suggestions for supporting science learning
and teaching in teacher education.
Finnish elementary school teachers are highly qualified, and it is a basic
requirement that they have a master’s degree. In addition, because of the high
popularity of the teaching profession in Finland, universities can select the most
motivated and talented applicants. However, our results indicate that pre-service
elementary school teachers’ understanding of photosynthesis was relatively poor
before they read the text, although most of the students had completed a basic
course on the pedagogy of biology for the elementary school level. These results are
in line with earlier studies (see, e.g., Ahopelto, Mikkilä-Erdmann, Anto, &
Penttinen, 2011; Mintzes & Wandersee, 2005; Ross et al., 2005). However, after
reading the text, the participants achieved significantly better results, and thus the
intervention was successful. On the delayed post-test, students’ scores decreased
only slightly from the post-test level.
Our results also indicate that the refutational text supported students’ learning of
photosynthesis more than the traditional, non-refutational text. According to
previous studies, a refutational text would mainly support a systemic level of
understanding, and facts would be as easy to learn from refutational as from nonrefutational texts (see Mikkilä-Erdmann, 2001; Diakidoy et al., 2011). However,
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unlike several previous studies, in our study the refutational text interestingly
appeared to be a more effective support for systemic and factual learning than the
non-refutational text. The effectiveness of the refutational text might be based on an
awakening of the reader’s meta-conceptual awareness, when he or she starts to
compare his or her previous conceptions with the contents of the text. Kendeou and
van den Broek (2007) conceptualise this phenomenon as co-activation, when
previous misconceptions and scientific ideas are active at the same time in one’s
working memory, which supports high-level learning. Another explanation for the
superiority of the refutational text could be that it may encourage active, reflective
and critical reading that helps students develop ‘scientific literacy’ (Wellington &
Osborne, 2009).
In our study, the refutational text seemed to especially support those students
with naı̈ve conceptual understanding regarding the connection between the concepts
of ‘photosynthesis’ and ‘nourishment’. These students did not understand how
concepts of nourishment and photosynthesis are linked to each other and, hence, did
not truly understand the nature of photosynthesis. In contrast, for those students who
had moderate or high previous knowledge concerning these concepts, it made no
difference whether they read a refutational or a non-refutational text. This result is
in line with earlier studies that have shown that students with low or inaccurate prior
knowledge benefit more from a refutational text than do students with a higher level
of previous knowledge (see Diakidoy et al., 2011; Kendeou & van den Broek,
2007). Broughton et al. (2010) suggest further that refutational texts would be more
helpful for older learners such as high school and college students than for younger
children. This presumably is due to the fact that older learners are usually better able
to reflect on their own understanding. These findings are important from a university
pedagogical point of view. Refutational texts could be used in teaching in science
classrooms such that they could support those students in higher education with a
weaker previous understanding.
However, designing meaningful interventions is demanding. Creating, for
example, an effective refutational text suggests that the researchers deeply
understand two very different things. On the one hand, they must know the
essential concepts concerning the topic of the text. On the other, they must also be
aware of the typical misconceptions and deficiencies in understanding about the
topic that often occur among the students for whom the text has been generated.
Thus, science teaching and learning research would benefit from multi-professional
work communities constituted of experts from different domains such as pedagogy
and science. As Duit (2009) comments, in many studies under the heading of
conceptual change, the major emphasis has been on implementing new instructional
methods, not on rethinking the representation of the particular science topic in
relation to the designed instruction (Duit, 2009). In our research group, a biology
teacher and experts on education participated in all phases of the study from the
design period to the reporting of results.
In this study, participants’ answers were analysed using a conceptual map in
order to clearly see if a learner had truly understood, first, the essential concepts
regarding photosynthesis, and, second, the interconnections between those concepts.
Using conceptual maps in learning enables the illustration of the systemic nature of
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scientific phenomena. Conceptual maps have been successfully used as facilitators
for learning or even as assessment tools at several levels of education over the
course of the last few decades (see, e.g., Kinchin, 2000a; Nesbit & Adesope, 2006;
Novak & Cañas, 2006). We believe that conceptual maps could be used more than
at present in teacher education, where students face the challenging goal of
mastering a huge amount of information from different disciplines. Hence, we
suggest that the results of this study could be exploited when creating digital
learning material such as conceptual maps for the purposes of domain-specific
science education in teacher education.
The following aspects need to be considered when generalising the results of this
study. The data were collected from one Finnish university, and further studies in
different cultures should be conducted. In terms of the texts, the refutational text
was slightly longer (584 vs. 490 words), and although the texts included the same
factual content, we still cannot be sure what exactly a refutation effect is. Using
methods such as eye tracking would enable further investigation of the learning
process and hence help answer this question. The problem in repeated measures
studies is that the participants have to answer the same questions several times. In
this study, participants answered the same open-ended questions three times,
although on the post-test they could refer to their earlier answers. This may have
affected participants’ motivation to answer the questions properly, although none of
the participants abstained from participating. Intentional interest is one aspect
affecting conceptual change, and although we chose participants for whom one
could assume photosynthesis was a relevant concept to be learnt, participants’
individual interest may have varied, which may have affected their learning results.
The fact that participants answered the same question three times in 2 weeks may
raise the question of the role of memory in the results. The delayed post-test was
administered only 2 weeks after the intervention, which is quite a short but realistic
time period for such a multidisciplinary curriculum. A longer time lapse is naturally
recommended when possible, because that would reveal, if the changes in
participants’ understanding were permanent. Concerning the factual questions,
memory may play a role in the improvement in participants’ answers. However, when
it comes to the systemic questions, which are complex and multifaceted, we assume
that it is not possible to give high-level answers based on memory. Regardless of the
risks, we wanted to keep the questions the same as per the idea of scientific control.
All in all, the development of domain-specific science education at the university
level is still in its infancy and needs further examination. The elementary school
teacher’s role as a science educator as well as a science learner presents extreme
challenges for teacher education. The process of teachers’ professional development
can be viewed as a series of substantial conceptual changes that pre-service
elementary school teachers have to undergo (Duit, Treagust, & Widodo, 2008). In
addition to reaching a conceptual change concerning the constructivist view of
learning and teaching, elementary school teachers have to master large amounts of
information from different disciplines such as biology, English, history and the arts.
Thus, conceptual changes are needed at several levels before they can attain
expertise in the teaching profession. Our study has implications for developing the
science curriculum and textbooks in teacher education, which involves independent
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studying across different domains. Using refutational texts would be an easy and
economical tool to promote an understanding of the most complex scientific
phenomena.
Climate change, famine and the threat of running out of fossil fuels are examples
of some of the most critical ecological, economic and human problems on Earth at
present. How individuals in western countries understand and conceptualise these
phenomena plays a crucial role when they consider their own behaviour (see
Carlsson, 2002; Ratinen, 2013). Understanding the reasons for these hazards and the
way their mechanisms function highlights the importance of basic science
knowledge concerning the phenomenon of photosynthesis. Not all of us reflect on
the fact that substances we consume everyday such as food, paper, wood, oil etc. are
produced by photosynthesising organisms and thus the fact that life on Earth
completely depends on these photosynthesising organisms and their ability to
change solar energy to chemical energy directly or indirectly and bind carbon
dioxide from the atmosphere. However, teachers are key players in shaping the
minds of future decision-makers and thus have the potential to affect future citizens’
readiness for sustainable learning and activity in the various domains of science.
Acknowledgments The authors wish to thank the Academy of Finland for the financial support for the
LeMEd-project, 128892 and lecturer Jorma Immonen from the Department of Teacher Education in the
University of Turku for co-operation.
Appendix
An example paragraph from the texts. The last paragraph was present only in the
refutational text, and it is italicised so as to highlight it. The section discusses food
chains, energy and matter:
Food chains illustrate how energy flows from one organism to another. Carrot
leaves bind solar energy in the process of photosynthesis, a rabbit gets part of
this energy by eating the carrot and, in turn, a fox gets part of this energy by
eating the rabbit. In each phase, part of the energy leaves the food chain. Thus,
only part of the energy the carrot originally photosynthesised ends up in the
fox.
Energy does not cycle in the food chain but enters the food chain only by
photosynthesis. Loss of energy from the food chain means that a carnivore at
the top of the food chain consumes much more energy for its growth than a
same-sized herbivore would need, because of more steps in the food chain.
In the food chain, matter cycles and returns from the top of the food chain to
the photosynthesising organisms. When a dead organism decomposes,
nutrients from it are released back to the soil. Plants can use these nutrients
again when they grow and photosynthesise.
Concepts of matter and energy are often confused. Matter cycles in nature so
that when a dead animal decomposes, nutrients are released back to the soil.
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Many people think that energy also cycles in nature, but this does not happen.
Energy has to continuously flow to the food chain. For this, photosynthesising
organisms are needed, because they are able to change solar energy to
chemical energy for other organisms to use.
[Translated from the original Finnish text used in the study. The authors can
provide a copy on request.]
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