Learning and Teaching Science

GOALS FOR SCIENCE LEARNING

Although there are ongoing efforts to encourage young people—particularly females and minorities—to pursue careers in science and technology, most researchers agree that the primary goal of K-12 science learning should be the creation of a scientifically literate population. Scientific literacy can be defined as a basic understanding of science, an appreciation of how science shapes society and culture, and the ability to reason scientifically. Many American adults lack the basic understanding of science that is required for making informed decisions about the many scientific issues affecting their lives. Therefore some educators go further, defining the primary goal of science education as providing students with the information and tools to become lifelong science learners who can adapt to the technological innovations that will be at the center of life in the 21st century.

For many educators learning goals have become synonymous with standards—national, state, and local school district determinations of what students should know, understand, and be able to do in scientific subjects at specific grade levels. National standards are delineated in the BSL and NSES.

The 2007 NRC report, Taking Science to School, cites the development of scientifically proficient students as a key goal: “Students who are proficient in science:

1. know, use, and interpret scientific explanations of the natural world;
2. generate and evaluate scientific evidence and explanations;
3. understand the nature and development of scientific knowledge; and;
4. participate productively in scientific practices and discourse” (p. 36).

K-12 science education standards usually cite scientific thinking as a primary educational objective, and competence in scientific investigation as a goal from the earliest grades. According to these standards students should be able to:

• Formulate a question;
• Design an investigation;
• Analyze data;
• Draw conclusions.

HOW STUDENTS LEARN SCIENCE

It has been apparent since at least the late 1970s that traditional methods of teaching science—lectures, textbooks, memorization of facts, theorems, and formulas— have little to do with learning science. Furthermore with the explosion in scientific knowledge in the latter half of the 20th century, information was often obsolete before it could even be taught. Rather, a large body of research has clearly demonstrated that children learn science by doing science—a process called inquiry-based learning, a form of constructivist instruction. With inquiry-based learning students investigate and discover on their own, in addition to reading and receiving instruction and guidance.

Inquiry-based science learning generally begins with observing, describing, and reflecting on objects and phenomena, leading to the formulation of questions and identifying assumptions about those objects and phenomena. Students then acquire more knowledge, using books and other sources to determine what is already known from experimental evidence. The next step in inquiry-based learning is to test explanations in a variety of ways. Students plan investigations and use tools to collect, analyze, and interpret data. They propose explanations, make predictions, and communicate their ideas, results, and conclusions.

Hands-on or exploratory learning stresses the importance of scientific experiences for developing skills. For young children these skills include observation and comparison, measurement, and classification, in addition to communication. More advanced skills involve inferring relationships, formulating hypotheses, and predicting outcomes. Students learn to identify and control variables, methods of gathering, organizing, and recording data, and how to draw conclusions.

CONCEPTUAL CHANGE

In contrast to the old-fashioned view that young children think in simple concrete terms, research has shown that the thinking of even very young children is quite sophisticated and that they are capable of thinking in both concrete and abstract terms. They utilize a range of reasoning processes—including causal reasoning and distinguishing between reliable and unreliable sources of information—that form the basis of scientific thinking.

Perhaps most importantly a large body of research has shown that children do not start school as blank slates upon which scientific knowledge can be written. Rather, children come to school with their own conceptual resources, already knowing a great deal about the natural world and having formulated their own scientific ideas. However, children also vary greatly in their early learning experiences and opportunities, which may be influenced by race, ethnicity, language, gender, culture, and socioeconomic background. Thus they differ in their conceptual resources and in what they are capable of learning at a given age.

Because many scientific concepts are not intuitive, children often have deeply entrenched misconceptions about nature, and these misconceptions often prove to be barriers to learning science. In the late 1970s cognitive researchers began interviewing students to assess their understanding of scientific concepts. They found that many students had trouble, not because the concepts were inherently difficult, but rather because they conflicted with the students' entrenched misconceptions. Furthermore, the memorization of scientific facts and formulas could disguise these underlying misconceptions. Among the topics about which students often hold misconceptions are force and motion, the particulate theory of matter, heat and temperature, electricity, optics, and evolution.

Learning science requires not just knowledge of key facts and concepts but an understanding of how facts and concepts relate to each other and their implications and applications. This may require a large-scale reorganization of knowledge and in-depth conceptual change to overcome prior misconceptions. These processes take time and require that children work with the same ideas and concepts in different ways over weeks, months, and years. According to Posner and colleagues (1982), four conditions must be met for conceptual change to occur: Students must be dissatisfied with their current conceptions because they conflict with observations or contain discrepancies; students must understand the new idea; they must be able to reconcile the new idea with their own ideas; and they must find the new idea useful and amenable to further testing.

Strike, Posner, and colleagues' general model of conceptual change applied the philosophy of science to the learning of science. Since then the conceptual change approach has become a basic tenet of teaching science. By first assessing prior knowledge, students' knowledge can be built upon, and misconceptions and potential misunderstandings can be addressed. The goal is for students to discover or recreate concepts on their own. Posner and colleagues proposed that having students work through problems with different explanations and compare the results led the students to recognize the shortcomings of their explanations and strengthened the scientific concept.

FURTHER THEORIES OF SCIENCE TEACHING

In addition to the importance of conceptual understanding, most contemporary theories of science teaching involve support for constructivist practices—active, inquiry-based, and collaborative strategies that utilize experimentation and other scientific methods to teach scientific reasoning within the context of specific science content. Because science is, in essence, a social process, research suggests that it should be taught as such, with emphasis on working in groups and whole-class and small-group discussions, questioning, and communication that enhance the development of scientific literacy.

Scientific discussions, explanations, and evaluation of evidence differ from those activities in other subjects and in everyday life. Students need instructional support to learn the language and practices of scientific experimentation, interpretation, and discussion. Many attempts at hands-on discovery learning have proved unproductive due to lack of guidance. In constructivist inquiry-based learning the teacher acts as a coach, introducing basic information and new concepts as required and guiding group discussions.

Finally, there is a consensus among researchers that science curricula, textbooks, national, state, and local standards and assessments contain far too many disconnected topics. Most research indicates that it is far more productive to focus on core ideas, which are explored in depth progressively through grades K-8.

EFFECTIVE INSTRUCTIONAL STRATEGIES

There exists a large body of research on effective means for promoting conceptual change. Building from misconceptions can be effective: For example, young children may find that their preconceived ideas about why weather changes conflict with their observations, so the teacher introduces the concepts of air movement and weather fronts. In a conceptual change approach the teacher provides an introduction, including a review and motivating experiences. This is followed by focus, in which the students observe an event, pose a problem, and formulate ideas and explanations. The challenge presents a conflicting question or discrepancy and the students then develop new ideas. Application involves solving problems using the new ideas and engages the students in discussion and debate. Finally, the teacher or students, or both, summarize the results and connect them with other lessons.

Discovery argumentation, using cycles of model-based reasoning, has been found to be effective with students from elementary school through high school. The bridging analogies strategy introduces a target situation in which the students' initial intuition conflicts with a scientific principle. This is followed by an anchoring intuition, a situation in which intuition agrees with scientific principle. At first the students see the two situations as completely different. A series of bridging analogies or intermediate models are then presented in which the situations are intermediate between the target and the anchor. Following cycles of reasoning the students develop a new model that they can test. Nuthall found that upper-elementary students required three or four experiences with new scientific ideas before the concepts enter their long-term memory.

Know-Want-Learn (KWL) charts help students visualize what they already know and what they want to learn and then conclude with what they have learned. Hershberger and colleagues (2006) have modified KWL to Know-Learning-Evidence-Wonder (KLEW), emphasizing observation, evidence, and further investigation. Yet another variation includes “know and think,” to encourage students to share their initial ideas and realize that what they think they know can change as a result of inquiry.

Research indicates that from the earliest grades designing and conducting experiments and investigations helps students understand scientific concepts. With guidance students can follow the scientific method by formulating hypotheses and designing and carrying out experiments and collecting evidence that is used to evaluate the hypotheses. This process conforms to several of the teaching guidelines presented in the AAAS's Project 2061 research-based Science for All Americans (1989):

• “Teaching should be consistent with the nature of scientific inquiry.”
• “Science teaching should reflect scientific values.”
• Scientific knowledge should be presented in the context of the processes by which it was arrived at.

Learning-cycle approaches can actively engage students in the processes of science through collaborative inquiry into interesting and familiar phenomena. First fully described in 1967 by Karplus and Thier, the learning-cycle approach alternates hands-on exploration and applications and “minds-on” activities through interactions with the teacher, other students, and texts. Over the years numerous studies have supported the effectiveness of the learning cycle, particularly when all three phases of the cycle are utilized, and exploration precedes the introduction of concepts and terminology.

Rodger W. Bybee's 1997 5-E model is a learning-cycle modification: Engage, Explore, Explain, Elaborate, and Evaluate. The Launch, Explore, Summarize (LES) model is a condensed version of the 5-E model. Aaron D. Isabelle (2007) has described applying the “storyline approach” to LES to incorporate conceptual change. Using questions, objects, or visuals the teacher elicits the students' prior knowledge and discusses the concept addressed in a story. The teacher then reads a story from the history of science, discusses the factual and fictional aspects of the story, and connects the ideas in the story with the original discussion.

Studies have repeatedly found that discussion is an important science learning tool for even the youngest students. Effective “talking science” can include practice using scientific terms in sentences, discussing intuitive theories, reading different types of science writing, and translating between scientific and colloquial questions and statements.

Finally, the guidelines set forth in Science for All Americans include:

• Teaching should include the history of science and societal and multicultural perspectives.
• Inquiry should lead to a satisfying conclusion.
• Curiosity and creativity should be fostered.
• Questioning should be encouraged and dogma avoided.
• The aesthetics of scientific phenomena should be emphasized.
• Local resources should be utilized.
• “Teaching should take its time.”

Consistent with this last point is a recommendation from researchers and reformers that students should study in great depth the core explanatory ideas in science rather than quickly traversing many different ideas, which permits only shallow understanding.

APPROPRIATE ASSESSMENT

Research has shown that large-scale standardized tests alone are not a valid method for assessing scientific understanding. Generally these tests measure knowledge of discrete pieces of information rather than structured knowledge of science. However ongoing, appropriately designed assessment is an important component of science teaching and learning. Performance-based or alternative assessments may include:

• Performing a task or experiment
• Describing an exploration or the solution to a problem
• An essay
• A portfolio
• Student-teacher discussions
• Worksheets
• Journals

Formative assessment is used by teachers to adapt instruction and by students to improve learning. Formative assessment involves a three-step feedback process:

• Setting a learning goal
• Assessing the gap between the goal and the student's understanding
• Using feedback to eliminate the gap.

For example, a teacher may learn from a series of questions that students have not understood a concept and decide to modify a subsequent lesson to reinforce that concept. Likewise, students may modify their own work after comparing it to the teacher's example.

Achievements to be assessed include:

• Inquiry skills
• Knowledge and understanding of facts, concepts, principles, laws, and theories
• Understanding of the nature and functions of science
• Scientific reasoning abilities
• Using science to make decisions and develop opinions on issues
• The ability to communicate clearly about science.

The Lawrence Hall of Science's Science Education for Public Understanding Program (SEPUP), an issue-based 6-12 curriculum, works with the University of California's Berkeley Evaluation and Assessment (BEAR) Center. The SEPUP/BEAR system scores students on five concepts and abilities:

• Designing and conducting investigations
• Identifying objective scientific evidence and evaluating various solutions to a problem on the basis of evidence
• Understanding concepts and their problem-solving applications
• Communicating scientific information, including explaining methodologies, presenting results, and justifying conclusions
• Group interactions including collaborating on tasks and contributing ideas.

CHALLENGES TO EFFECTIVE INSTRUCTION

Research has consistently identified teacher proficiency as a major challenge in science education. Most K-8 teachers have little background in science and little training in teaching science. Schools often struggle just to teach basic literacy and math skills, and the science curriculum may be nonexistent. Many teachers tell researchers that the major impediments to their science teaching are their own lack of knowledge combined with inadequate facilities, supplies, and preparation time. Furthermore, children arrive at school with very different experiences and attitudes toward science. Recognizing and addressing these differences poses a special challenge to teachers.

The inquiry-based approach, which requires teachers to guide student experimentation and discussion while incorporating specific learning goals, is a major paradigm shift for many teachers. In addition preparation for government-mandated high-stakes standardized testing and the demand that teachers strictly adhere to applicable science standards are often incompatible with student-centered, hands-on science instruction.

Finally, most science curricula and textbooks provide neither continuity for students nor guidance for teachers. Project 2061's analysis of science textbooks found them to be of almost uniformly poor quality, superficially covering a large number of topics with little attention to concepts. Although researchers agree that the science curriculum is far too broad, there is little agreement about which topics to emphasize and which to eliminate.

RESEARCH-GROUNDED CURRICULUM PROJECTS

Concept-Oriented Reading Instruction (CORI) is a research program that integrates science inquiry and reading using the following support strategies to motivate students:

• Student autonomy
• Competence
• Learning goals
• Real-world interactions.

Elementary students are introduced to a complex domain such as ecology or the solar system. After several weeks they select a specific topic within the domain and choose related books to read. They receive help in finding and using resources and communicating what they have learned. Students also participate in related activities such as field trips, collecting, and experimentation. In a study of third and fifth graders in three schools, CORI students, as compared with students in the traditional science program,

• Reported greater interest in reading science
• Exhibited better reading comprehension of science texts
• Scored higher on standardized tests.

Several innovative curricula connect students with other students and with professional scientists. In the Global Learning and Observations to Benefit the Environment (GLOBE) project K-12 students worldwide study earth sciences in partnership with scientists. GLOBE has been shown to improve math, science, and geography skills, and students and teachers report increased interest in and awareness of environmental issues and satisfaction at having contributed to scientific research.

The Web-based Integrated Science Environment (WISE), developed by Marcia Linn and her colleagues, uses browser-based inquiry activities that enable middle and high school students to critique evidence, compare scientific arguments, and design solutions to scientific problems. WISE projects are interdisciplinary scientific issues and include hands-on data collection, online modeling, and design activities, as well as peer interaction and collaboration. The Center for Learning Technologies in Urban Schools (LeTUS) has developed very influential curriculum projects. The center is a collaboration of researchers at the University of Michigan and Northwestern University with Detroit and Chicago public schools. The center has developed inquiry-based instruction that has been shown to promote growth in conceptual understanding and reasoning. Students engage in projects around “driving questions,” core explanatory questions about interesting topics that motivate inquiry. The North Dakota State University World Wide Web Instructional Committee (WWWIC), an interdisciplinary research team, has developed multi-user, interactive virtual environments (IVEs) for teaching high-school science. In “Geology Explorer” students examine an alien planet and conduct geologic tests. In “Virtual Cell” students enter a simulated cell and perform biological experiments. A decade of research has shown that IVEs improve student achievement and problem-solving skills.