Research over the last forty years reveals four potential barriers to learners developing successful science understandings B prior experiences and beliefs, language, a learner's preferred way(s) of meaning making, and culture. In this article, I consider two questions B in what ways can each of these four potential barriers inhibit learners' understandings and what are the implications of not addressing these potential barriers?

Prior Experiences as a Potential Barrier

Before children enter school, they construct descriptions of the world around them that may be different from the descriptions scientists use. Using interviews and observing children solving problems, researchers from a number of countries are interested in the kinds of explanations children develop about their world (Driver, 1985, 1994; Harlen, 1992, 1996; Pfundt & Duit, 1991). One thing seems clear; even young children are likely to hold on to their own explanations about the world despite what they are told in school. Unless students are faced with experiences that challenge their conceptions, they are unlikely to change their models of how things work or accept alternative explanations/descriptions as useful or important (Suping, 2003).

For example, what is a bounce? Young children are likely to say a bounce is what happens when something hits the floor or wall and doesn't break. With a number of more years of schooling, the preservice teachers in my "Introduction to Teaching Science" course describe a bounce as an object changing direction when it hits another object and that pieces of broken objects can bounce. When pushed, they say that even if it is only millimetres the object must leave the floor or wall to be considered a bounce. Both of these explanations are different from the current scientific definition of bounce.

Within the science community, a bounce is described in terms of a collision. A collision occurs when any two surfaces come into contact; collisions are either elastic or inelastic. Why do scientists find it easier to think of the contact of one object with another as a kind of collision? Most likely, because they explored more kinds of objects contacting one another than one person would encounter in their own environment. For scientists, the definition of bounce used by children to get around the house and stay out of trouble when throwing the ball is just not adequate. DiSessa (1983) calls these childhood concepts developed prior to formal instruction phenomenological primitives. These explanations are embedded in the learners' models of the world before they are introduced to scientists' explanations. One outcome of these differences in explanations is that science appears to be "unnatural." When we teach science as the way the world works, science descriptions carry a sense of truth. What happens to the learners' own explanations of the world? If the science descriptions are in conflict with explanations held by the student, by other people in the student's life, or by people within the student's culture, we may create conflict within the student. Especially, if we treat the science description as the truth, require that in school you will give the scientist's answer and, as a result, discredit other explanations.

Language as a Potential Barrier

There are a number of ways language can make understanding science more difficult, such as alternative meanings of words, students' lack of appropriate vocabulary, the specialized vocabulary used by scientists, and English as a second language. A second outcome, for children who cling to their own explanations, may be a feeling of disenfranchisement. Students may begin to separate school explanations and home explanations. Or, students may begin to believe they are unable to learn science--it is just too difficult to figure out. Still others may reject the science explanation as all too unplausible and accept their own or their community's explanation instead.

Learners may develop an understanding of the meaning of certain words that is different than the scientists' meaning for these words. People outside the science community and scientists themselves give these same words other meanings and/or use them in other contexts, resulting in slight nuances to the original meaning. These alternative meanings can make understanding and/or accepting the scientist's use of the word or term difficult. For example, the concepts living and nonliving are commonly introduced in the primary grades. The meaning of the terms living and nonliving are confounded by the meaning of the terms alive and dead. Interviews with primary-aged children reveal that many of them consider cars, batteries, and fire as living and not unreasonably so. In everyday language we describe those and other nonliving objects as being alive, e.g. a live wire or the fire "came to lift" when we added wood, or as having died, e.g. the car or battery died. Learners also have trouble accepting that wood for the fireplace, bones that their dogs chew, and leather gloves are categorized by scientists as living.

Community is another concept often introduced in elementary school. Scientists define a community as the interaction of living organisms within a bounded system. A community could vary in size from a drop of water to a log or pond or entire forest depending where the boundaries are established. Within the general culture, communities are determined by groups of residents who have some common identity. Communities in this sense focus on the activities, needs and care of human beings. A scientist on the other hand treats the human being as one species among many, with a specific habitat (address) and niche (job/function) within the community.

A final example is the concept force. We talk about force as one aspect of a field of influence surrounding objects. That is, a force field is a complex of pushes and pulls. However, the everyday use of the term force includes such phrases as, "I was forced to go to bed without my dinner", "Someone forced their way into the house", "My Mom works on the police force," and in the movies, "May the force be with you." Young learners must grapple with a range of meanings for most terms. How do they decide which is the "right" meaning or which meaning is "right" in which situation? These distinctions may be some of the most challenging aspects of learning science there are and contribute to children's beliefs that science is unnatural.

There is a gap between our ability as learners to observe and the language available to communicate our observations and thoughts; between what I call knowledge and information. Exploring the properties of objects is common throughout students' science learning. Some of these properties are colour, smell, shape, size, weight, distance, texture, taste, sound, flexibility, chemical reactivity, and pattern. Students may find it difficult to be "successful" observers in each of these areas if they lack the vocabulary to capture and share their observations. For example, students may know there are differences in sounds or colour, but lack vocabulary to differentiate particular colours or sounds. How many smells are we able to describe only as "stink"; how large is our stink vocabulary? It seems this gap is even more problematic when learners are unable to articulate ideas which they "feel" they know but are unable to defend their choice of solution or explain how they decided on an answer beyond a shoulder shrug or "I don"t know." Consequently, I believe students who say, "I know, I just don't know how to explain it."

When asked to develop a list of words that describe various properties, preservice teachers can list fifty or more in each category. The English language is rich in synonyms to capture nuance. If we want to close the gap between what even young learners are able to observe and think we must provide them with the sensory vocabulary to share their ideas and understandings. In addition, scientists use words that are not used in everyday language. One study indicates that over 750 new science related terms are introduced from kindergarten to grade six (Scruggs & Mastropieri, 1993). In addition, some young learners require more time than others to develop reading and writing skills. If they are expected to understand that the meaning of words can change in different contexts, the task of reading and writing can be that much more difficult.

Science language can be even more challenging for ESL learners, especially if science words have different meanings within the school or community. When students are learning the school language as a second or third language, the student's intellectual, social, and physical capabilities may be masked. Research indicates that language can interfere with students' test results and interactions between students and their teachers (Mastropieri & Scruggs, 1991).

Culture as a Potential Barrier

Culture is the milieu in which a person lives; there are multiple cultures in our lives which we either participate in or observe. A learner may move from home to community to school to religious or social group to sports group in the course of a day. Some of these cultural encounters mesh seamlessly with our expectations. We are comfortable there and even like being there. Other cultural encounters are different and don't meet our expectations B we are less comfortable or may feel alienated. Science is an enterprise B it is something a group of people do and as such, there is a culture of science. What happens when learners are introduced to/encounter the culture of science in schools?

Most of us teach in increasingly multicultural classrooms. Young learners often come to school with different explanations of the same phenomena that scientists are interested in describing. Whether from family, religious or other cultural origins, these explanations may make accepting the science descriptions problematic. As with models of the world, young learners construct from their own experiences. These cultural models may be considered "natural" while the science explanations are considered "unnatural" or "counter intuitive." Another consequence of differing explanations is that young learners could be "caught" between their culture and their teacher. Having to choose between explanations valued in school and those valued by their parents and/or members of their community can cause stress and perhaps rejection of one view or the other.

The culture of science itself is poorly represented in the experience of many young people. The problem is not just insufficient science in the school curriculum, but that science and technology are presented in the schools from a knowledge-based perspective, typically divorced from social, political, and ethical considerations and debate. Such problems are most acute in relatively rural, economically-undeveloped areas such as Atlantic Canada, where the lack of technical and scientific infrastructure outside the schools gives students little exposure to science and technological culture through avenues other than the standard school curriculum. The dominant cultural group (science versus other knowledge or dominant versus minority groups) does not always value and/or understand other cultural groups. Young students may come from local traditions that may be different than those of their teacher or schools. For example, the way the children interact in school and interact with their family and community may be different in terms of what knowledge, measures of success, or behaviour are valued.

Neglect of science-as-culture can lead to a clash of culturally-based, local knowledge with scientific knowledge and the culture it represents. The well-documented failure of communication between fishers and federal fisheries scientists that contributed to the collapse of the Newfoundland cod stocks in the early 1990s is a vivid example of this dangerous problem. Finlayson (1994) documents how federal scientists charged with managing fish stocks often ignored the information and insights of local resource users, while resource users in turn mistrusted scientists and lacked sufficient understanding of their methods and aims to enter into a dialogue. The result was an environmental and human tragedy rooted in a clash of cultures.

If students are to be prepared for a technological world, and if the school science reform is to positively impact all students, then teachers, researchers, and policy-makers have to recognize the culture of science and how it is reflected in the schools. A well-documented consequence of not dealing with the culture of science and technology is that student interest in science and mathematics typically fades after the early grades. Fewer students opt for post-secondary concentrations, and attitudes and opinions about science shared by students and parents are shaped more by popular culture, mass media, and entertainment than by formal learning in science classrooms (Osbourne, 2003; Peacock,2000; Schibeci & Lee, 2003; Solomon, 1996).

Preferred Ways of Learning as a Potential Barrier

Educators believe we all have preferred ways of making sense of the world. The challenge is finding a way to describe these different ways of making meaning; more challenging is finding ways to teach that first address and later expand each student=s ability to learn in different ways. Different models have been developed to describe these preferences B learning styles and multiple intelligences are examples of current models. Learning styles models suggest people prefer to understand the world by relying on one or two of their senses predominately. These preferences are referred to as learning modalities or in some cases, learning styles. The four modalities most often recognized are visual, auditory, tactile, and kinesthetic. One study suggests attending to students= learning styles results in improved achievement scores and behaviour (Klavas, 1994). In that study, where over half the students preferred tactile or kinesthetic modalities, students were presented concepts first in their preferred learning styles, next in their second for practice, and finally reviewed the ideas verbally. According to another learning styles researcher, science needs to be taught as more than a subject and a method. Some learners= styles connect with the world less through logic than with aesthetics and feelings, through affective avenues, personal commitment, and acting (Samples, 1994).

Howard Gardner (1993; 1995) proposes another model which he calls multiple intelligences. Gardner defines intelligence as abilities to solve problems recognized as valuable within a culture. He identifies eight intelligences -- linguistic, logical-mathematic, spatial, musical, bodily-kinesthetic, interpersonal, intrapersonal, and naturalistic -- as a staring point in the discussion and argues that there may be other intelligences or even subintelligences. In posing his theory of multiple intelligences, Gardner argues that "school should be to develop intelligences and to help people reach vocational and avocational goals that are appropriate to their particular spectrum of intelligences" (p.9). He contends that linguistic and logical-mathematical intelligences are most valued in schools today and that learners whose strengths are not in those areas often find school an unsuccessful experience.

Even when the spectrum of intelligences is identified, young learners can face difficulties in having their particular strengths and interests recognized. Although there is growing evidence that broadening our notions of intelligence and using an activity-based as well as language-based assessment instruments provides us with better information about young learners, Gardner argues the work in this area must be considered promising but not conclusive. Most instruction, especially in middle and high school, favours visual and auditory learning styles and linguistic, logical, and mathematics intelligences over others. Moreover, school science portrays the processes used by the science community as visual/auditory and logical/linguistic when we know imagination and creativity are also necessary.

While educators acknowledge we all learn differently, it is important to note that there is less agreement about which of the models/theories best accounts for that difference (Miller, 2001; Oneil, 1990; Stellwagen, 2001). As educators, we need to sort through the literature for ourselves and decide which models provide the best insight to address the needs of our students.

In Conclusion

Until we begin grade by grade, unit by unit, experience by experience to consider the possibility of potential barriers to learners understanding scientists= ideas and ways of working, we will continue the present pattern of most students having negative science experiences and feeling disenfranchised. Students will continue to choose not to study science when given the choice and not to pursue science careers. Most high school students will become adults who are uncomfortable discussing science and who feel incompetent to challenge the science ideas and research that impact their lives.

There is considerable research describing students= alternative conceptions of scientists= explanations and definitions. Science education leads the research in this area with researchers in social studies and other disciplines beginning to build on their research. What we need is to apply the research locally. Each of us as teachers needs to look critically at the science curriculum for concepts, language, and experiences that could act as potential barriers for our students understanding science. Once these potential barriers are identified, we need to make talking about them with students -- that is, confronting the discrepancies between our everyday beliefs and explanations with scientists= explanations B part of the content of our curriculum.

The consequence may be that we need to reduce the number of science concepts we want students to learn initially and provide them time and experiences that allow them to grapple with these differences. If learners acknowledge that scientists think and work differently than others and explore ways in which scientists think and work, we will have more students who are more comfortable with and want to participate in the culture of science.

References


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