Editor's Note: Nancy Moreno is associate professor in the Department of Family and Community Medicine and associate director of the Center for Educational Outreach at Baylor college of Medicine, Houston. Trained as a botanist, she now focuses on developing collaborations among scientists and educators and leads science education partnerships funded by the National Institutes of Health, the Howard Hughes Medical Institute, and the National Science Foundation.
Many candidate races and ballot initiatives in the November 2006 United States elections highlighted science-related issues and debates. Stem cell research, alternative fuels, and climate change were topics considered in regional and national discussions (Brumfiel et al. 2006). To understand and choose among conflicting viewpoints, voters needed to possess two aspects of scientific literacy: (1) comprehending science concepts and (2) understanding how science builds knowledge. Unfortunately, statistics compiled by the National Science Foundation indicate little headway in improving the second aspect of science literacy—understanding the nature of science. In 2004, for example, only 23% of adult respondents could correctly “explain in their own words what it means to study something scientifically” (NSB 2006).
We science educators face important challenges. May we assume that students will understand the nature of science because they participate in inquiry-based lessons? Or must we provide explicit opportunities for students to examine the knowledge-building process? Scientifically literate citizens, for example, might need to be familiar with the roles of scientific debate, ethics and oversight of experimentation, the importance of evaluating sources of scientific information and the process of reaching consensus. Ask yourself if your students are able to grasp competing arguments, such as those related to human-induced global warming. Is the issue of climate change merely a hoax, as some argue? Or is there a scientific basis for raising fuel economy standards to reduce carbon dioxide emissions?
My colleague, Barbara Tharp, and I recently wrote about strategies that can help students learn science (Moreno and Tharp 2006). To comprehend challenges confronting voters and other decision-makers now and in the future, students must have learning experiences that foster deep understanding of the nature of scientific research. As we consider priorities for science education in the 21st century, it will be critically important to develop students’ abilities to interpret and apply scientific information. In preparing your next course or class, consider whether the following themes appear in your curriculum.
Science does not proceed in a linear fashion. The scientific method, per se, is not emphasized in the National Science Education Standards (NSES). In fact, we find the following statement in the Science as Inquiry content standards for grades 5–8 (NRC 1996, p. 144): “This standard should not be interpreted as advocating a ‘scientific method.’ The conceptual and procedural abilities suggest a logical progression, but they do not imply a rigid approach to scientific inquiry.” Yet some textbooks still portray the process of science as a straight-line progression of steps along the lines of identify a problem, form a hypothesis, conduct an experiment, gather and interpret data, communicate results and conclusions, and possibly identify new questions. This series of tasks typically is identified as the Scientific Method. Many teachers, even in elementary school, rely on science activity worksheets that force students through this process. In such a restrictive environment, many students lose interest in science at an early age. In reality, science is conducted in a much more open-ended and creative way than most students are taught—and most adults realize. As physicist Jerry Pine (1999) noted, “scientists move back and forth among processes to refine their knowledge as the inquiry unfolds.”
Science is based on questions. The day-to-day work of scientists is guided by the search for answers to questions. When Science, the journal of the American Association for the Advancement of Science, celebrated its 125th anniversary in 2005, the editors highlighted 125 hard questions that pointed to critical knowledge gaps. They chose questions such as, “Why do humans have so few genes?” “What can replace cheap oil and when?” and “Can the laws of physics be united?” (Kennedy and Norman 2005). Significantly, the journal did not choose to describe these knowledge gaps as statements or prevailing hypotheses. Many students have the misconception that the work of scientists involves stating a hypothesis and designing an experiment to examine that hypothesis. But, most scientists think of their work in terms of questions. In addition, possible explanations (hypotheses) change frequently. An investigator might consider multiple explanations simultaneously. These alternative competing explanations can be described as “working hypotheses,” which change as new knowledge and insights are acquired. In the end, great questions , not an inflexible “scientific method,” have driven great science (Siegfried 2005).
Not all science involves controlled experiments. Consider a geologist, an astronomer, or a paleontologist. Although their activities fall within the realm of science, they rarely, if ever, conduct controlled experiments. Instead, they rely on detailed observations of nature to identify patterns of change over time or across locations. A biologist who is asking whether two similar-appearing groups of plants diverged from a common ancestor cannot go back in time and observe or perform experiments on the speciation process. Instead, he or she must use other forms of evidence, such as DNA sequences, to estimate the degree to which the groups are related. Because the various branches of science differ in their methodologies and in the questions they pose, no single process moves all “science” forward. Comparative and observational methodologies are just as important as experimental ones to advance scientific knowledge.
Scientific knowledge is tentative. Knowledge contributed by science is being modified continuously. Questioning established ideas is critical to the advancement of scientific understanding. Many examples demonstrate how accepted views have been challenged and reformed by new evidence. In medicine, for many years, physicians and scientists attributed stomach and intestinal ulcers to factors related to stress and lifestyle. This belief became standard among medical professionals. Drs. Robin Warren and Barry Marshall, however, demonstrated that almost all stomach and intestinal ulcers are caused by a bacterium, Heliobacter pylori (Nobel Foundation 2005). This discovery, which won them the Nobel Prize in Medicine in 2005, ran counter to conventional thinking and completely changed the way in which ulcers are treated by physicians. Now peptic ulcers are no longer considered to be chronic conditions. Instead, they are cured by a short regimen of antibiotics and acid secretion inhibitors. If these scientists had not challenged the fixed ideas about what causes ulcers, this new explanation and treatment would not have emerged.
Some teaching strategies promote deep understanding of how science works. How can you help students think profoundly about how science builds knowledge? Look for science teaching materials that use different experimental approaches or that allow students to develop their own testable questions. Help students understand which types of questions can be examined scientifically (see BSCS 2005 for an activity that addresses scientific questions). Besides conducting controlled experiments, expose students to inquiry activities that rely on methods of observation and comparison to reach a conclusion. Conduct class discussions about alternative explanations of observations and outcomes of investigations. Instead of just seeking the “right” answer, emphasize the need for students to justify their conclusions based on evidence. Use examples from print and broadcast media to introduce competing scientific viewpoints, and allow students to compare and contrast those views. And most importantly, encourage students to view scientific discourse as a productive part of the evaluation and advancement of scientific knowledge.
Unless we explicitly include in our teaching the second dimension of science literacy—understanding of the nature of science—our students may not be able to evaluate scientific information based on its source and how it was generated (NRC 1996). Our future depends on the abilities of young citizens to think through competing explanations and make informed decisions about science issues that affect us all.
To review the complete reference list, visit http://science.nsta.org/enewsletter/references2.pdf.
For more information on the NSTA Press book Teaching Science in the 21st Century that inspired this series, visit http:store.nsta.org/showitem.asp?product=PB195x.