Students' Scientific Explanations and
the Contexts in Which They Occur
E. David Wong
Michigan State University
Elementary School Journal, 96(5), 495-511. 1996
Abstract
The goal of this analytical essay is twofold. First, I analyze examples of
middle school students’ reasoning in science to illustrate (a) that the
distinction between students’ and scientists’ reasoning is ambiguous
rather than obvious, and (b) that there are good reasons why students do
not, cannot, and should not always reason and act as scientists do.
These examples are drawn from my 2 years of science teaching with atrisk, inner city students. The second goal of this essay is to develop a
useful conceptualization of reasoning in context. As research in this field
develops, it is critical that the conception of “context” not become vague or
all-inclusive, thereby diminishing its analytical usefulness. To facilitate
discussion and analysis, I propose 3 dimensions of context that seem to
have an important influence on students' scientific reasoning: (a) the
knowledge and technology available to students, (b) the sociolinguistic
context and related norms that implicitly define appropriate reasoning,
such as the expected purpose, precision, and level of explanations, and
(c) the expectations, values, and dynamics of school communities that
influence student behavior.
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The Difference between Students and Scientists
The goal of science education has always been to develop a more
scientifically literate public. Frequently, the image of the scientist has
been a model for ideal scientific reasoning and what a science program
should strive to develop in K-12 students. In this tradition, important
psychological research has emerged from the expert-novice paradigm to
highlight differences between students and scientists and to suggest goals
or directions for subsequent learning and development.
Comparisons between students and scientists have focused
primarily on differences in conceptual knowledge and reasoning. An
abundance of psychological and instructional research documents
students' naive conceptions (also referred to as misconceptions or
alternative frameworks) about scientific phenomena. These studies have
concentrated mainly on (a) describing differences between students' and
scientifically accepted explanations (Driver & Easley, 1978; Novick &
Nussbaum, 1978), and (b) designing and implementing instructional
strategies to change students' conceptions (Anderson & Smith, 1986;
McCloskey Caramazza, & Green, 1980; Osborne and Freyberg, 1985).
Similarly, research by developmental and cognitive psychologists has
provided descriptions of the reasoning process of children, adult
nonscientists, and scientists. These studies have typically analyzed how
individuals make inferences from observation, distinguish between
theories and observations, and construct and modify theories (Carey,
Evans, Honda, Jay, & Under, 1989; Karmiloff-Smith, 1988; Kuhn, 1989;
Schauble, 1990).
A logical consequence of these perspectives that emphasize
deficiencies in conceptual knowledge and thinking strategies might be that
in order to reason more scientifically young students need to acquire more
accurate subject-matter knowledge and develop more sophisticated
reasoning skills. Instructional programs designed to foster students'
reasoning skills have shown some promise at improving students'
performance in certain situations (c.f. Palincsar, Anderson, & David, 1993;
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Roseberry, Warren, & Conant, 1989). Conceptual change science
curricula aimed directly at the diagnosis and treatment of misconceptions
have produced promising changes in students’ explanations of scientific
phenomena (Anderson & Smith, 1986; Hewson & Hewson, 1983;
McCloskey et al., 1980; Osborne & Freyberg, 1985).
The importance of having a solid conceptual knowledge of science
is irrefutable: problems, phenomena, or issues are understood as
instances of a particular scientific idea or concept. Similarly, in order to
solve problems or to develop explanations, individuals must also be able
to employ appropriate strategies to bring together what they know,
observe, and generate in a logical, sound manner. However, scientists'
and students' reasoning is distinguished not only by variations in
conceptual knowledge and reasoning skills but also by differences in the
conditions or contexts in which reasoning occurs.
The Analysis of Reasoning in Context
When individuals think about scientific phenomena and discuss their
ideas and explanations, they do so in a particular context. This assertion,
by itself, is a truism: thinking always occurs someplace. However,
suggesting that the particular intellectual, cultural, social, and physical
character of that context might shape individual and group reasoning is a
more interesting and important proposal. Research on scientific and
mathematical activity in other ethnic cultures, workplace contexts, and
other everyday settings has highlighted important features of learning and
reasoning in formal and informal learning settings (Brown, Collins, &
Duguid, 1989; Heath, 1982; Lave, 1988; Lave, Murtaugh, & de la Rocha,
1984; Lave & Wenger, 1991; Martin & Scribner, 1991; Resnick, 1990;
Saxe, 1989; Saxe, 1991; Scribner, 1984). This research has
characterized how learning and understanding are influenced by
contextual factors such as social and cultural norms, interactions with
other individuals, the nature of the task, and the available physical tools
and objects.
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Most of these studies have focused on the learning and practice of
mathematics. Saxe (1992) observed that mathematics may be
particularly well suited for this kind of analysis because it is a well
delimited domain, the nature of students’ problem solving is manifest in
their actions, and mathematics allows a relatively clear specification of
what counts as more and less complex forms of mathematical operations.
By contrast, scientific understanding and practice have received
significantly less research attention. Perhaps within the dominant
comparative paradigm, cases of informal, workplace, or cross-cultural
scientific learning and reasoning are difficult to identify, characterize, and
contrast. Furthermore, a distinct description or definition of scientific
literacy may be difficult to produce. In research about both mathematical
and scientific reasoning, conceptions of what constitutes legitimate
literacy remain open to constant clarification or revision. Comparative
studies consistently suggest that powerful and legitimate ways of
reasoning about mathematical tasks can be found in informal as well as
traditional disciplinary settings.
The study of students' scientific practices and the context in which
they occur must be approached with prudence. First, since the definition
of scientific practice or literacy is nebulous, the study of such practices is
challenging. Second, the definition of context is equally, if not more,
ambiguous. Although the surrounding environment may influence the
substance and process of scientific reasoning, context can quickly
become a vague or all-encompassing term, thereby diminishing its
analytical usefulness.
In this article I focus on one activity of scientific practice: the
construction of explanations about natural or technological phenomena.
Other activities of scientific practice (e.g. designing careful investigations,
constructing a logical argument, appreciating beauty) are related and
important, but I leave their analysis to others. In addition, I avoid
assertions about the influence of context as a general factor. Instead, one
goal of this article is to sharpen and promote future analysis of the
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contextualized nature of scientific reasoning by highlighting three features
of the environment that seem to play an important role:
(a) the knowledge and technology available to students,
(b) the sociolinguistic norms inherent in a context that
implicitly define what "counts" as reasoning, and
(c) the expectations, values, and dynamics of school
communities.
A second goal of this article is to encourage a closer examination
of the relation between students’ and scientists’ thinking. Two
assumptions are implicit in the much of the research on science learning
and science instruction: (a) students generally do not reason like
scientists, and (b) students should learn to reason as scientists. A
growing and compelling body of research, however, suggests that
students' existing knowledge and ways of reasoning are rarely arbitrary or
senseless. Instead, reasoning strategies used by students and scientists
alike are frequently learned, functional ways of thinking in particular
contexts (e.g., Brewer & Samarapungavan, 1991; Karmiloff-Smith, 1984).
Further research on reasoning in various contexts can reveal both ways
that students are like scientists and ways that scientists are like students.
Such research is also likely to reveal compelling reasons why students do
not, cannot, and should not always reason and act as scientists do.
Classroom Context
For 2 years, I worked as a regular science teacher, within an "alternative
education" program, for a low-income, urban, middle school science class.
Students in this class had been identified by their seventh- and eighthgrade teachers as severely disruptive, academically at-risk, or both.
Sixteen students were enrolled in the class, with slightly more boys than
girls. All students were African-American; the school’s population was
95% African-American. For 18 weeks, these students spent their entire
day (with the exception of lunch and elective classes) in this class
covering all subjects with the alternative education teacher and a small
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team of assistants such as myself. After two quarters in this program,
they returned to their regular classes. Frequently, such pull-out programs
are little more than glorified in-school suspension. In this case, however,
the alternative education program was explicitly intended to provide a
supportive environment suited to these students’ particular academic and
social needs (e.g. small classes, home visits by the teacher, special
couselors, employment opportunities).
The unique and flexible nature of this program provided an
opportunity to teach science in nontraditional ways. In particular, I was
interested in understanding and facilitating students' efforts to construct
their own explanations for scientific phenomena. In my role as the
teacher, I made a concerted effort to encourage students to generate,
elaborate, share, evaluate, and modify their own ideas. The students
themselves were responsible for the substance and direction of our class
discussions. I saw myself as a facilitator of their thoughts and energy
rather than as an authoritarian source of correct scientific knowledge (for
other examples of studies of context in instructional settings see Cobb,
Wood, & Yackel, 1991; Schauble, Klopfer, & Raghavan, 1991).
The Effect of Knowledge and Technology on Reasoning
In the following example, students' explanations might be judged as
scientifically incorrect when evaluated in light of standard textbook or
canonical explanations. However, considering the conceptual and
empirical information available to the students reveals the reasonableness
of their explanations. This example also illustrates how the construction
of explanations - by scientists and students alike - is enabled and
constrained by contextual features of situations in which explanations
occur, such as available knowledge and technology.
Explaining Why a Candle Goes Out
One scientific phenomenon that my science students examined
involved baking soda, vinegar, and a candle. A 3-inch utility candle is
mounted inside a 5-inch tall, 800 ml glass beaker. The candle is lit and a
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teaspoon of baking soda is carefully placed at the bottom of the beaker.
Then, about 50 ml of vinegar is poured slowly down the side of the
beaker. The mixture bubbles gently and the candle soon goes out. When
attempting to relight the candle, one finds that the match goes out before
it can reach the wick of the candle (See Fig. 1).
Students were quite intrigued by this phenomenon and were eager
to provide an explanation. The three most popular explanations students
offered stated that the flame was extinguished by (a) the "wet mist" from
the fizzing mixture, (b) moisture that "seeps up the candle wick", or (c) a
"puff of wind" produced by popping bubbles. None of these accounts
corresponds to the accepted "scientific" explanation that maintains that
the vinegar/baking soda reaction produces carbon dioxide that fills the
beaker and extinguishes the flame. By many criteria, the students’
explanations would be labeled as misconceptions, incorrect, and
unscientific. Is it appropriate, then, to conclude that the students'
explanations are unscientific?
During class I persistently asked students to explain their ideas. As
they attempted to justify their ideas, it became evident that although these
three explanations did not correspond with that of a physicist or chemist,
they were reasonable in light of (a) students' prior knowledge, and (b) the
evidence available. For example, as middle school students, they
undoubtedly understood that flames can be extinguished by putting water
on them or by blowing them out. Students’ explanations suggested that
they were attempting to apply this knowledge. The students' speculations
were neither capricious nor arbitrary: no one suggested "magic" or
invented a fire-extinguishing "force".
In essence, students constructed their explanations by integrating
an idea or concept from their prior knowledge with empirical evidence
associated with the phenomenon. This process is both scientifically
authentic and logically sound; it is what scientists do. In fact, it is the only
means by which anyone can generate rational explanations. Also, most
students clearly sought observational data to develop and support their
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explanations. Proponents of the "wet mist" explanation cited sizzling
noises from the candle and visible droplets of water on the walls of the
beaker as evidence that moisture was extinguishing the flame. Students
who suggested that moisture "seeps up the wick" also cited the sizzling
noises as evidence that the wick was wet. The "puff of wind" explanation,
although advocated by more than one student, was not supported by
observational evidence.
Available Conceptual and Empirical Information
Examining the students' explanations in the context of their prior
knowledge and the available empirical data complicates the traditional
distinction between students' and scientists' explanations. Judging from
prior and subsequent discussions, I inferred that these students did not
have a well-developed understanding of carbon dioxide, its properties, or
how it can be produced. It is difficult to imagine how they could possibly
have generated an alternative to their explanations without this
knowledge.
It can be argued that the students in this situation were generating
explanations that were rational rather than "correct." Contemporary
philosophical perspectives also contend that since most scientific
explanations have eventually proven fallible, the notion that scientists
have a claim to "correct" theories is untenable. Therefore, like the
students' explanations, scientific theories can, at best, only strive for
verisimilitude, or what Popper (1972) described as an ever-improving
approximation of reality.
Both students' and scientists' explanations are also affected by
access to empirical information and use of technological equipment. For
example, the scientifically accepted explanation for why the candle goes
out is founded on the assumption that carbon dioxide is produced by the
reaction between the baking soda and vinegar. How does one come to
realize or verify that carbon dioxide is produced?
Carbon dioxide gas is invisible. In many science curricula, a
common activity that accompanies the candle demonstration involves
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collecting the gas produced by the baking soda and vinegar mixture and
bubbling it through a limewater solution. The collected gas turns the
limewater cloudy and, therefore, "proves" that the gas is carbon dioxide.
In reality, all that is proven is that this procedure makes the solution
cloudy. Whether the gas is, in fact, carbon dioxide and not some other
gas remains underdetermined. Science (not scientific) activities (not
experiments) in schools rely heavily on students accepting without
question these kinds of empirical or conceptual "givens." This kind of
"proof by intimidation" discourages students from raising critical questions
like, How did it come to be known that CO2 causes limewater to turn
cloudy? Someone at some time had to identify a substance as CO2
before the limewater test . How do you know you have a particular
substance apart from such tests? Another important and fair question
might be, Do other gases cause the same reaction?
Available Technology
Modern technology enables scientists to observe other properties
of a gas so that mass and composition can be more precisely inferred (not
observed directly). Unfortunately, students do not have access to such
instruments, and thus such information is unavailable to inform their
reasoning. Greeno (1989), Brown et al. (1989), and researchers in the
ethnographic tradition of Lave and Scribner have suggested that cognition
can be examined usefully as a relation between an individual, the tools or
technology, and the physical properties in a situation. The concepts of
situated cognition and affordances emphasize that individual and group
reasoning is both constrained and enabled not only by prior knowledge
and reasoning skills but by the physical context.
For example, how might students’ reasoning have been influenced
if they had used magnifying glasses to observe the vinegar and baking
soda reaction? What if they had used a videotape camera and had been
able to view the reaction repeatedly, at different speeds, or as freezeframes? These technologies not only provide new information, but they
also invite new kinds of questions and investigations. I can only speculate
9
about what could have happened with these students. However,
acknowledging the situated nature of reasoning leads one to imagine that
these different technologies could enable students to construct different
representations of the phenomena. Associated with variations in
representations is the potential for different kinds of reasoning and
explanations.
In the science community, explanations can only be judged in the
context of available theoretical and empirical information. Although
students might access more sophisticated theories and empirical
evidence through a teacher or textbook, in the immediate realm of
students' knowledge and experience, such information is often
unavailable. Evaluating students' explanations solely on the basis of a
comparison to expert scientists might lead a teacher or researcher to
conclude that students not only do not have the correct background
knowledge, but that they are also unable to reason logically. Although
these inferences are often warranted, these kinds of comparisons run the
risk of creating artificial distinctions between students and scientists. In
the candle example discussed previously, when explanations are
considered in the context of what is known and what information can be
obtained, the reasoning of both students and scientists appears
reasonable and rational.
The Sociolinguistic Contexts of Explanations
The candle activity illustrated how the appropriateness of explanations
might be evaluated in light of available conceptual and empirical
information. With the next examples - a series of short conversational
exchanges about how household appliances work - the focus shifts to an
examination of how sociolinguistic features of a situation influence
students’ explanations. Specifically, the role of purpose, intended
audience, and circumstance is explored.
The Function of Explanations
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One day I asked students what seemed to be a relatively simple
question, "How does a light bulb work?" With unanimous and enthusiastic
agreement, they said, "You turn the switch on!" With great curiosity, I
asked, "Can you say more about how a light bulb works?" The students
seemed perplexed and looked at me as though I were hard of hearing.
One student spoke in a slow, slightly impatient tone, "Like we said...you
walk over to the wall, push the switch up, and the light goes on."
Given their familiarity and experience with light bulbs and the
rudimentary ideas about electricity that are typically introduced in the
elementary grades, I had anticipated that students would mention
something about the flow of electricity, the heating of the filament in the
bulb, and the emitting of light. I was fairly certain that they had the
appropriate subject matter knowledge with which to discuss the “science”
of light bulbs...under different circumstances. Later I asked how students
thought a microwave oven works. "You push the buttons on the front,"
they responded. Similarly, when asked why baking soda and vinegar
create bubbles when mixed, students explained, "because you pour the
vinegar into the beaker fast" (i.e., the faster you pour the vinegar, the
more the solution will fizz). In most scientific communities, attributing the
cause of these physical phenomena to procedures is usually not
appropriate. Many students, however, interpret questions about why
something happens as requests for information about how one makes
something happening (Carey et al., 1989). A "scientific" account explains
a phenomenon in terms of the interaction of the elements within a system,
that is, the different electric components or the vinegar and baking soda
compounds. These students seemed to be providing an instrumental
account that described the steps needed to make a phenomenon occur.
In a sense, they were providing instructions that others could follow.
I should emphasize that in the scientific disciplines, the character of
explanations is diverse rather than monolithic. For example, Gregory
(1990) and Feynman (1990) suggested that Kepler’s astronomy
represented a dramatic change in the character of explanation in physics.
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Prior accounts of the motion of celestial bodies included ideas of
“impetus” and “angels wings” in an effort to explain why the motion
occurred. Kepler’s work completely ignored the mechanism of movement
and instead used the language of mathematics to describe the relation
between masses and motion. Similarly, the question of how gravity works
has been approached from different perspectives in physics. Some
theories have proposed entities and causal mechanisms (e.g. curved
space) that help to account for why masses are attracted to each other.
However, a significant contribution has been a mathematical description
of gravitational attraction. Although these formulas do not represent
causal mechanisms, they have been important and useful because they
precisely describe “how” mass, distance, force, and acceleration are
related to one another.
Why explain? This simple question captures what I believe is a
critical element for understanding the process of explanation construction
and why explanations develop a particular form and content.
Explanations occur in many different situations, each characterized by
subtle, often implicit features that influence the function of explanations
and what reasoning is considered appropriate. A typology of different
functions of explanations could be a powerful conceptual tool that would
illuminate the features of a given explanation. Explanations can be
constructed for a wide range of reasons, including:
- to satisfy a curiosity,
- to provide aesthetic pleasure,
- to accomplish something else,
- to inform someone else,
- to demonstrate competence,
- to rationalize an idea or action,
- to reduce fear of the unknown.
How Explanations Might Change with Purpose and Context
Comparing different functional contexts for explanations might be
useful. For example, how might explanations differ when their function is
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either to demonstrate competence or to satisfy a curiosity? Students
would probably be less willing to reveal ambiguity, persistent questions, or
doubt when they respond to a teacher’s question or take a test than when
they attempt to satisfy their own curiosity. In many situations,
competence is associated with not asking questions, minimal pondering,
and absence of doubt. However, when pursuing one’s own questions, the
act of thinking itself - considering difficult issues, taking new perspectives,
and uncovering deeper puzzles - is often most pleasurable and valued.
Explanations might also differ in purpose depending on whether the
explainer is a teacher or a student. The teacher strives to foster learning,
whereas the student hopes to demonstrate competence. Furthermore,
teachers and students hold different assumptions about what their
audience is likely to know, understand, and expect. As a result, the
teacher is likely to explain in a manner that is more structured and more
explicit and to check for understanding frequently. Students’ explanations
may be more implicit or understated either because students assume the
teacher will understand or because they fear that the more they say, the
more likely they are to make a mistake and be judged as performing
poorly.
In schools students' explanations are usually given in response to a
direct request from a teacher. Tasks of this sort typically represent
opportunities for students to demonstrate competence or reveal
ignorance. Almost always, the teacher already knows the "correct"
answer and is not asking the question so that students can help the
teacher learn something. Students might also construe explanation tasks
as random assessments, as a means to control a class, or as stepping
stones upon which a discussion proceeds. Lemke (1990) characterized
student-teacher interaction as the "activity" structure of classroom
discourse that provides a predictable, manageable routine for both the
students and the teacher. Lemke also argued that because of the
authoritarian nature of much science teaching, the activity structure
13
established by many science teachers and students frequently militates
against authentic scientific activity.
Solomon (1986) also described different "modes" of explanation to
illustrate how the purpose and content of explanations can vary. For
example, a child may ask why his or her peers at school are so mean.
The parents' explanation of "that's the way some people are" hardly
describes any causal links but instead provides a measure of empathy by
supporting the child's observations and reactions. In other situations, a
student may explain that energy is "strength and power," thereby
responding in a semantic rather than an analytic sense. Neither of these
examples constitutes an explanation in the traditional scientific sense.
However, situations do not warrant an analytic, causal explanation.
Precision and Level of Explanations
Two additional features implicit to engaging in scientific discourse
in a particular social context are the expected precision and level of
explanation. "Pragmatic precision" (Hawkins & Pea, 1987; Lave et al.,
1984) refers to the exactitude required in a communicative situation. For
example, paleontologists describe time in units of millions of years;
computer engineers require nanoseconds. As another example, whether
something is about "15 to 20” or 17.4 depends not on the actual quantity
but on the precision required by the social context in which the quantity is
given. Fifteen to twenty may be appropriate when discussing with one's
family the number of purple finches seen feeding at the backyard feeder.
The quantity of 17.4 might be required when describing the average
number of birds in a field survey of bird behavior, or in response to a
question on a high school chemistry test that emphasizes significant
figures.
In addition to differing in precision, explanations also vary in the
level of sophistication at which phenomena are described. For example,
the following explanations could be given for why the flame goes out when
vinegar and baking soda are mixed:
- because the vinegar and baking soda were mixed
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together,
- because vinegar and baking soda fizz,
- because a gas is produced,
- because the gas displaces oxygen,
- because combustion requires oxygen.
Successively more sophisticated levels of explanation can be
derived simply by asking "why.” When I attempted to push my students to
a deeper level of explanation, in some cases, they would not understand
or see the point of "saying more". The puzzled looks on their faces
indicated that they felt that the question had been “asked and answered.”
In other cases, students continued to explain but confused level of
explanation with detail of description. Whereas I hoped for an elaboration
of the link between the fizzing and the flame being extinguished, students
instead tended to embellish of their prior explanations. For example,
initial explanations from students might state that the candle was put out
because the vinegar and baking soda fizzed. When I asked them why this
is so, students continued to explain that baking soda and vinegar began to
make bubbles when the vinegar was poured into the beaker.
Many students were eventually able to produce more sophisticated
accounts of the phenomenon, suggesting that their explanations were
influenced not only by their subject-matter knowledge but also by their
expectations for what counted as a “good” explanation in science class.
A critically important task for me as the teacher was to negotiate with
students the sociolinguistic context, that is, the expectations for what “say
more, please” meant, what constituted an appropriate explanation, and
what our respective roles were in the instructional process.
The roles and expectations for how the students and I talked about
explanations were quite different from those in the students’ traditional
science classes. Furthermore, not only did I expect students to explain at
a more sophisticated level than the one to which they were accustomed, I
constantly urged them to move to a “deeper” level of explanation. My
predictable request for them to say more or explain further may have
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created the impression that no level of explanation was, in fact,
acceptable to me. The criteria for success in my class thus had less to do
with providing a particular response than with the spirit and intention to
construct ideas that were progressively more sophisticated. Admittedly,
such teacher expectations are unorthodox, and, with the benefit of
hindsight, I must admit that participating in my class must have been an
unsettling experience for some students.
To summarize, an analysis of the sociolinguistic context of
explanations reveals that the appropriateness of an explanation can be
judged by the degree to which it is commensurate with the particular
purpose, level, and precision required by a situation. Since students will
function in a variety of situations, they need to learn that different contexts
exist, how to recognize and distinguish them, and how to respond
appropriately in each.
The Evaluation of Ideas in Social Contexts
When examining the construction of explanations, one might consider two
processes: the generation of ideas and the evaluation of those ideas.
Although these processes are interrelated, some analytical power may be
gained by this distinction. To this point, I have discussed the influence of
knowledge, technology, and sociolinguistic conventions on the generation
of explanations. Many philosophers of science argue, however, that it is
not the production of ideas that distinguishes reasoning as "scientific".
Instead, Lakatos, (1970), Popper (1988), and Thagard (1988) are
unanimous in their belief that one of the distinguishing features of a
science is a willingness to evaluate, modify, and discard explanations.
Popper pointed out that mysticism, psychoanalysis, and Marxism -doctrines sometimes identified as "non-sciences" -- cannot be faulted for
the inadequacy of their explanations. In fact, pseudo-sciences are
frequently characterized by a preponderance of explanatory capacity and
can typically account for just about anything. According to Popper, it is
the inability and unwillingness of supporters of these ideas to test and
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modify them that marks them as unscientific. In scientific communities, an
explanation -- and the act of explaining -- is dynamic in that it is always
being evaluated, modified, and regenerated. In the following section, I
shift from an emphasis on the generation of explanations to an
examination of how the surrounding social context influences the
evaluation and modification of ideas.
The Roles, Expectations, and Values of Students and Scientists
The students in my middle school science class generated three
major explanations for why the mixture of baking soda and vinegar causes
the candle to go out. These included:
- moisture from the fizz spatters and douses the candle
flame,
- the bubbles from the fizz burst and blow out the candle,
- the fizz produces a gas that causes the flame to go out.
After writing each account on the board, I asked students what they
thought about the existence of three explanations for the same
phenomenon. In scientific communities, differences among explanations
are a critical impetus for scientific inquiry and discussion. However, my
middle school students simply shrugged their shoulders and seemed quite
comfortable with the fact that different people had different ideas. Some
reasonable interpretations of their reaction might be that they did not have
sufficient knowledge of the content, reasoning strategies to evaluate these
explanations, or interest in constructing their own explanations. Although
none of these possibilities can be ruled out, in the following section I
explore another interpretation: evaluating their own ideas is an activity that
students find unfamiliar, uncomfortable, and frequently unproductive.
It is important first to compare this activity of student generation
and evaluation of explanations to other student-teacher interactions in a
typical school day. At the simplest level of analysis, the teacher makes a
request for information and students provide it: this is the most common
pattern of teacher-student interaction (Cazden, 1986; Lemke, 1990). In a
typical interaction, after the student responds to a teacher question, the
17
teacher evaluates the appropriateness (usually the correctness) of the
response. Usually, and unfortunately, students are responsible for being
on their toes and getting all answers correct. Teachers’ questions keep
students engaged, enable the teacher to assess student learning, or,
unfortunately in some cases, function as punishment. In addition,
teachers often ask students questions to focus students on the topic for
the day. For example, a lesson on weather might begin with a few
questions about what students thought about a recent cold snap. After a
few minutes of discussion to pique their interest in the topic or "activate
prior knowledge," as theorists might say, teacher-centered instruction
begins, often with minimal connection to students' comments.
The kind of scientific activity in which I was trying to engage my
class, however, assumes a very different set of roles and responsibilities
for the teacher and students. In curricula that are truly student centered,
students' ideas provide the principal substance for future discussion and
learning (Hammer, 1994). Furthermore, the students, not the teacher,
have primary responsibility for evaluating students’ responses. I had a
strong sense that the students were waiting for me to judge which
explanation was most appropriate and then to get on with the "real"
science lesson in which I tell them why a particular explanation is better
than others. On numerous occasions students made comments at the
end of class such as, “Well, aren’t you going to tell us the answer?” The
more impatient ones would remark during the middle of a discussion,
“You’re the teacher. You tell us.” Some students, in an attempt to make
sense of these unusual student and teacher roles, were prompted to
conjecture aloud, “You don’t really know the answer, do you?”
The students' inability to evaluate their own explanations, therefore,
can be understood best by considering how most classrooms function.
My prior experiences with these students made me doubt that they lacked
the ability to criticize each others' ideas. The success of any activity in a
classroom is influenced not only by what the students know how to do but
also by what they think they are supposed to do. Changing the
18
fundamental nature of classroom interaction and learning is a difficult,
long-term process. New roles and responsibilities must be negotiated,
made explicit, and practiced by both the students and the teacher. Also, a
system of rewards and reinforcements must be established to change and
maintain new intellectual and behavioral norms (Anderson & Palincsar,
1994; Ball, 1993; Lampert, 1990; Palincsar et al.,1993).
Tension between Disagreement and Conformity
Students’ passiveness not only suggested that they were being
asked to behave in an atypical manner but also could have indicated that
students viewed evaluating one another’s answers as aversive. Middle
school students frequently seek to belong to a social group; they value
conformity and harmony. The practices of science -- where the ability to
analyze another person's ideas critically is valued and rewarded -- may
conflict with peer social norms. During one of my science classes, I tried
to engage students in the exploration and critique of their peers’
explanations. The results were disturbing; students became visibly upset
and defensive, and their verbal and physical reactions revealed hurt and
anger. Some students leaped out of their seats at each other. Some
voices were raised, wheras others fell in silent in protest. These reactions
revealed to me that these inner city students sought social harmony not
only as a natural part of their adolescent development, but, the typically
unstable, unsafe nature of their out-of-school world may have created a
special, urgent need for peace and security at school. Therefore,
engaging students in particular scientific practices such as critical analysis
of each other’s ideas presented a formidable instructional and ethical
challenge to me because it seemed to work against some students’ desire
and need for conformity, harmony, and peace.
As I tried to create a community of scientific practice in my
classroom, I also learned that it is important to consider how students are,
in fact, taught to resolve differences with others. I had the opportunity to
observe a guest speaker talk with my students. In an effort to address the
problems of violence that characterized this school and its surrounding
19
community, the administration had organized a series of special
presentations on "conflict resolution." The main messages of most
presentations of this kind are: avoid taking criticism personally,
understand the other side of an issue, and attempt to negotiate a
compromise. The overarching goal is to maintain harmony among
individuals who work or live together. In most social and political settings,
the understanding of and ability to engage in this kind of process are
invaluable. However, in scientific settings, where the principal goal is to
advance ideas rather than to maintain social harmony, the function and
value of compromise and negotiation are not as clear.
Do arguments lead to consensus or contrast?
What is the role of argument in the scientific community? Charles
Anderson (Personal communication, April 12, 1992) suggested that
scientific argument is an effort to seek "consensus without coercion."
When different ideas and perspectives exist within a scientific community,
implicit conventions and procedures for argumentation are the accepted
means by which such conflicts are adjudicated. Although the requirement
for logical reasoning and empirical evidence clearly has contributed to the
growth and sophistication of scientific knowledge, the benefits of rigorous
argument in my middle school classroom were less obvious. Not only did
engaging in critical dialogue sometimes disrupt the existing social norms
and harmony of the classroom, but the process also seemed to inhibit the
social construction of knowledge - the central process of scientific inquiry.
At times, individuals representing opposing explanations for a
phenomenon actually became more entrenched in their views as they
defended their respective ideas. Questioning or criticizing explanations
rarely seemed to prompt students to generate alternative ideas. If they
did not give up on their ideas reflexively, they continued to elaborate their
ideas, sometimes straying further and further from what they understood
and observed about the phenomenon.
Instead of facilitating progress, argumentation often led to greater
polarization. Social psychologists have documented this phenomenon
20
extensively in studies of jury deliberation (Myers & Kaplan, 1976). I was
also reminded of the presidential debates that were taking place at the
time. In that context, the dialogue between political candidates suggested
that consensus or progress in thinking was antithetical to that kind of
argumentation. Instead, participants in these highly visible media events
seemed to strive to emphasize differences and incompatibility between
each other’s ideas.
Care must be exercised, however, when comparing scientific
discussions to political and legal debates. Political debate frequently is
characterized by a loose obligation to empirical evidence and principled
reasoning. Furthermore, political and courtroom argumentation is
adjudicated by a third party; voters, jurors, or judges decide the validity
and value of each viewpoint. In the scientific community, greater
responsibility is placed on participants themselves to resolve differences
in their ideas.
To summarize, an examination of the social context of schools
suggests that “poor” reasoning performance may be attributed to inhibitive
social factors in addition to deficient conceptual or strategic knowledge.
Initiating and sustaining intellectual tension between individuals
undermines other social norms of harmony and conformity. Furthermore,
in classrooms, students may hold different expectations than scientists for
how conflicting ideas are resolved, that is, the teacher provides the correct
answer or a compromise is negotiated. Finally, in many social contexts
the purpose and result of argument are antithetical to the mutual
construction of better understanding or to consensus building. It is not
surprising, then, that students might quietly doubt the value of arguing
about different explanations.
A critical examination of the efficacy of argumentation also raises
the question of how argumentation facilitates progress in scientific
communities themselves. Faust (1984) argued that scientists are
attached at a deep personal level to “pet” theories and are extremely
reluctant to consider disconfirmatory evidence. Scientists employ an array
21
of strategies, including developing ad hoc additions to their theory and
questioning the evidence against their theory, to preserve their ideas and
beliefs. It is important to note that these kinds of strategies (e.g., holding
onto an idea in spite of minimal empirical or collegial support) frequently
facilitate, rather than inhibit, the progress of science.
Conclusion: Implications for Research and Instruction
The emphasis on the relation between context and reasoning might be
usefully characterized by a biological analogy. Although nature's
creatures often act in unusual or unexpected ways, these behaviors can
be understood better when the scope of examination is broadened from
the individual organism to include the relation between the organism and
its surrounding environment. Similarly, students' reasoning can be
appreciated better when considering how their reasoning responds to and
is shaped by the intellectual, sociological, and physical contexts in which
they live.
There are important research and instructional implications for a
"functional/adaptive" perspective on scientific reasoning. First, instead of
dismissing students' reasoning as fraught with misconceptions and
handicapped by sloppy thinking, the students' naive wisdom and nascent
reasoning skills might be viewed as the foundation on which more refined
scientific knowledge and reasoning might be developed. Realizing that
incorrect explanations are often based on sound reasoning and real
observations or experiences helps explain the intransigence of
misconceptions to change (Smith, 1993). An alternative model of
instruction might encourage such "wrong-headed" thinking to continue
and be refined rather than to cease and be replaced. Duckworth (1987)
called this "giving reason" to students' ideas.
Second, highlighting the rational and functional nature of both
students' and scientists' reasoning challenges the conventional image of
the practice of science. Perceptions maintained by the public and by
scientists themselves frequently portray science as an elite profession
22
where, by virtue of innate aptitude, only a small group of individuals have
the ability to be true scientists (Tobias, 1990). Francis Bacon's assertion
that "the scientific method allows ordinary people to do extraordinary
things" has probably never been received wholeheartedly by the scientific
community on the grounds that it challenges the prevailing ideology of an
elite scientific community. Minority groups, who have traditionally been
excluded from the inner circle of scientific communities, are articulating an
increasingly urgent and clear message that the elite nature of science has
more to do with institutional, political, and cultural factors than with
knowledge and reasoning skills
Third, if reasoning is functional and adaptive to the surrounding
environment, then not only should students' conceptual understanding
and reasoning skills be developed, but also their ability to interpret the
nature of different contexts in which scientific knowledge is applied. In
addition, individuals need to understand how scientific reasoning is similar
to and different from other forms of thought, language, and action
(Fahnestock, 1988; Michaels & O'Connor, 1990). Issues associated with
scientific reasoning in different contexts might include: what is the
difference between explaining how stereo loudspeakers work to a class of
elementary school students, to a repair technician, or to a group of
scientists at RCA? What is the difference between how one comes to
understand fruitflies in the laboratory and factors affecting the health of
one's own children? What determines when formal experiments are
feasible, necessary, or appropriate? The nature of the situation in which
explanations occur affords and constrains reasoning and determines what
kind of language and action is most appropriate. Individuals who are truly
scientifically literate adapt to the unique demands and features of different
contexts (Wong, 1994).
Fourth, a functional/adaptive perspective on students’ reasoning
implies that a range of contexts for scientific reasoning needs to be
identified and distinguished. In what "niches" or contexts does scientific
reasoning occur, and how can reasoning be adaptive to each (Hawkins &
23
Pea, 1987)? Currently, K-12 science curricula tend to highlight a
specialized form of scientific reasoning (logical experimentation). This
kind of inquiry may be prevalent in some experimental physics or
chemistry research, but it fails to represent a large portion of actual
scientific practice. A wider range of activity needs to be considered and
valued as legitimately "scientific". From chemists to naturalists, from
theoreticians to applied engineers -- the manner in which explanations are
constructed and evaluated will vary according to the goals of the work, the
social-linguistic conventions of participation, and the practical constraints
on inquiry.
Finally, in addition to elaborating and distinguishing contexts
among different scientific disciplines, it is equally important to identify the
nature of effective scientific thought and action in everyday, informal
settings. Learning the practice of a particular discipline may not always
benefit individuals in situations outside the scientific community. Since an
overwhelming majority of students do not go on to become practicing
scientists, the challenge to science educators is to examine closely the
nature of scientific reasoning as it does and, more importantly, could
occur in other contexts. What is the nature of the problems, what are the
sociological and practical constraints, and what types of curricula best
prepare individuals to reason in these contexts?
24
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Figure 1
The vinegar, baking soda, and candle phenomenon
Vinegar an d baking
so da are ad ded to a
beaker with a lit
candle mou nted
ins ide.
The vin egar and
bakin g s oda bub ble
gently. So on, the
candle g oes ou t.
30
When attempting
to relig ht the
candle, the match
goes out b efore
reach ing the wick.