The Alberta Teachers’ Association

Dougal MacDonald and Brenda Gustafson

Alberta Science Education Journal, Volume 38, Number 1, November 2006, Journal of the Science Education Council of the Alberta Teachers' Association—Wytze Brouwer, Editor

The main goals of science teaching are generally stated as content knowledge (concepts), cognitive skills (for example, designing experiments) and attitudes (for example, respect for evidence). Another historically important goal has been to teach students about the nature of science (NOS). NOS is not about specific science content but about matters applicable to science as a whole; for example, how scientific investigations are carried out, standards defining acceptable scientific explanation and the reliability of scientific knowledge.

Why teach children about the nature of science? Overall, it contributes to students’ scientific literacy. Specifically, many good reasons can be given (Collins et al 2001). Teaching about the nature of science helps achieve the following:

· Helps science education offer value to all stu­dents, not just those pursuing a science career.

· Clarifies how classroom scientific inquiry is based on the work of scientists.

· Enlightens students about the inner workings of science (for example, how hypotheses are tested).

· Helps create citizens who can think critically about science-related discoveries (for example, critically evaluating the results of the tests of a new drug).

· Helps create citizens who can contribute intelligently to decisions about science-related issues (for example, genetically modified foods).

· Gives students insight into the difficulty of con­structing reliable knowledge about the world.

· Helps students understand not only what we know but also how we know (for example, how the theory of plate tectonics became accepted in geology).

· Helps to explain and justify why science is considered a rational enterprise (for example, why we should give credence to a theory, such as natural selection).

Science teachers convey an image of the nature of science to students even if they do not do so explicitly. For example, teachers who have students carry out and write up all classroom experiments in the same way may erroneously convey to students that there is such a thing as the scientific method. This suggests that science teachers should (1) consciously teach about the nature of science and (2) convey an authentic notion of the nature of science when doing so.

Further, students will not necessarily develop an authentic notion of the nature of science simply by doing authentic science. For example, students will not necessarily better understand the role of evidence in scientific inquiry just by finding evidence to support their explanations. More realistically, the teacher needs to

· decide on appropriate nature of science goals,

· meaningfully intertwine NOS goals with other lesson goals (for example, knowledge and skills) and

· make the NOS goals explicit to students during the lesson.

(Gustafson and MacDonald 2005)

A consensus on the nature of science

What is an authentic notion of the nature of science? Disagreement among science educators, scientists and others on this question will likely persist, but teachers need some basis to work from, so a consensus among most critics would be useful. One such consensus is presented in the documents of Project 2061, a long-term initiative by the American Association for the Advancement of Science (AAAS) to promote scientific, technological and mathematical literacy.

The Project 2061 consensus on NOS is validated by the lengthy collaboration of over 400 scientists, engineers, science educators, philosophers of science and others who developed it. The result is found in Science for All Americans (AAAS 1989). The article’s internal headings are useful for teacher knowledge and for teaching about NOS because they are framed as statements about NOS. The headings or statements are grouped under three categories:

Scientific worldview

·The world is understandable.

·Scientific ideas are subject to change.

·Scientific knowledge is durable.

·Science cannot provide complete answers to all questions.

Scientific inquiry

·Science demands evidence.

·Science is a blend of logic and imagination.

·Science explains and predicts.

·Scientists try to identify and avoid bias.

·Science is not authoritarian.

Scientific enterprise

·Science is a complex social activity.

·Science is organized into content disciplines and is conducted in various institutions.

·There are generally accepted ethical principles in the conduct of science.

·Scientists participate in public affairs both as specialists and as citizens (AAAS 1989).

Focusing on the nature of scientific inquiry

Because the recommended approach to teaching classroom science is scientific inquiry, it is useful to pay special attention to ideas about the nature of science relevant to scientific inquiry. The second section of the Project 2061 article on NOS specifically addresses scientific inquiry, and a close reading suggests a number of teachable ideas about NOS that expand on the more general statements made in the article headings. These ideas may need to be rephrased and/or simplified, depending on students’ ages, abilities and backgrounds:

Scientific methods

·Scientists agree generally on what is a valid investigation but there is no fixed set of steps that scientists always follow.

·Scientists resolve the validity of scientific claims by referring to observations of phenomena.

·Scientists use their senses and instruments to gather accurate data through observations and measurements.

·Scientists gather data in both natural settings (forests) and under controlled conditions (in laboratory experiments).

·Scientific arguments follow the principles of logical reasoning (in how con­clusions are inferred from evidence) (AAAS 1989).

Role and nature of hypotheses

·Formulating and testing hypotheses are fundamental scientific activities.

·Scientists use tentative hypotheses to seek, choose and interpret scientific data.

·To be useful, a hypothesis should be testable and should suggest what evidence would support it and what evidence would refute it (AAAS 1989).

Invention and discovery

·Inventing hypotheses and theories requires logic, close examination of evidence and creativity.

·Scientific discoveries require a combination of knowledge and creative insight (AAAS 1989).

Theoretical explanations

·Scientists produce knowledge by making observations of phenomena and inventing theoretical explanations to make sense of them.

·Theoretical explanations should use or be consistent with currently accepted scientific principles.

·Theoretical explanations must be logically sound and incorporate a substantial body of valid observations.

·Theoretical explanations often gain acceptance by showing relationships among phenomena that previously seemed unrelated.

·Theoretical explanations should have predictive power and should fit both known observations and additional observations not used in formulating the theories (AAAS 1989).

Bias and authority

·Biases may influence the choices, recording, reporting and interpreting of scientific data.

·Scientists are alert to bias in their own work but objectivity may not always be achieved.

·It is appropriate in science to turn to knowledgeable people as sources of information and opinion, however, no scientists are believed to have special access to the truth and there are no pre-established conclusions that must be reached (AAAS 1989).

Theory change

·New scientific theories may encounter opposition from the scientific community in the short run; however, in the long run, theories are judged by their results.

·When a scientist proposes a new theory that explains more phenomena or answers more questions than a previous theory, the new theory eventually becomes established in its place (AAAS 1989).

Strategy one: Scientific inquiry

Many important ideas about the nature of science can be explicitly taught within the context of scientific inquiry (Gustafson and MacDonald 2005):

· While scientists agree generally on what constitutes a valid investigation, there is no fixed method or set of steps that they always follow. Student groups compare and find differences in how they conducted an investigation into light and shadows, but also note similarities; for example, each group tried to control the same variables.

· Scientists use their senses and instruments to gather accurate data through observations and measurements. Students provide examples of observations and measurements they made during their investigation, and the role played by instruments (for example, using a thermometer to track the temperature of melting ice cubes).

· Scientists gather data in both natural settings and under controlled (laboratory) conditions. Students describe how an uncontrolled investigation (for example, observing different shapes of leaves on trees) differs from a controlled investigation that they engaged in (for example, testing leaves for chlorophyll).

· Biases may influence the recording, interpreting and reporting of scientific data. Students give examples of where they tried to explain results that contradicted their existing ideas (for example, insisting that an ammeter registered different amounts of current in a circuit before and after a bulb when all other groups found the amount of current to be the same).

· Scientific arguments must adhere to the principles of logical reasoning. Students outline how their conclusions about the connection between bird beak shape and type of food were inferred from the evidence that they gathered during a simulation activity.

· The validity of scientific claims is eventually resolved by referring to observations of phenomena. Students resolve a debate over the result of a test by repeating it (for example, using iodine to determine if cornstarch is part of a mystery mixture of three white powders).

· To be useful, a hypothesis should be testable and should suggest what evidence would support it and what evidence would refute it. Students frame a hypothesis using an If … then … format so they can test it (for example, “If the mineral fizzes when acid is dripped on it, then it is a carbonate”).

· Scientific theories should be logically sound, incorporate a substantial body of valid observations, and use or be consistent with currently accepted scientific principles. Students explain how their theory (for example, their explanation for why a hot air balloon ascends to the ceiling of the room) meets the above three criteria.

Strategy two: History of science

Teachers can also address NOS goals through familiarizing students with the history of science. Current science textbooks generally present summaries of up-to-date scientific ideas, often without reference to their historical development. Students may be left with the erroneous impression that scientific knowledge is a collection of unchanging facts requiring little or no justification. Because the history of science shows how scientific ideas change over time, studying it can help students better understand how we know as well as what we know. Studying the history of science is particularly useful in helping students understand the nature of scientific theories, because many historical accounts focus on the creation and testing of new theories (Gustafson and MacDonald 2005):

· Scientific knowledge is generated by making observations and inventing theoretical explanations to make sense of them. Students are familiarized with the story of how Fleming realized penicillin’s antibiotic properties when he observed that colonies of bacteria in a Petri dish stopped growing where mould existed.

· Theoretical explanations often gain acceptance by showing relationships among phenomena that previously seemed unrelated. Students are familiarized with the story of how the theory of plate tectonics came to be accepted as an explanation for such diverse phenomena as earthquakes, volcanoes, fold mountains, seafloor spreading and oceanic trenches.

· Theories are validated by their predictive power. Students are familiarized with the story of how the astronomer Leverrier used anomalies in Uranus’s orbit to predict where to find the then unknown planet Neptune in the night sky.

· New scientific theories may encounter strong opposition in the short run, but in the long run they are judged by their results. Students are familiarized with the story of how Wegener’s idea of continental drift was rejected then later accepted.

· New theories arise when they explain more or answer more questions than previous theories. Students are familiarized with the story of how Darwin’s theory of natural selection replaced Lamarck’s theory of inheritance of acquired characteristics as the explanation for adaptation (for example, the long neck of the giraffe).

Strategy three: Current science-related events and issues

A third strategy for teaching about the nature of science concerns science in the news. Almost daily, the media contain stories of science-related events and issues that include references to the nature of science, though those references are often only implicit. For example, Norris and Phillips (2003, 234) state that “Texts contain expression of the wide range of degrees of doubt and certainty applied to statements in science” and discuss whether it is a factual assertion or a tentative hypothesis that there is an ocean beneath the frozen crust of Europa, one of Jupiter’s moons.

The January 20, 2006, issue of the Edmonton Journal includes the following three headlines and accompanying news stories:

· “United States the next front in city company’s cold war” (This article was about marketing Alberta-developed COLD-fX in the United States.)

· “Wandering whales worry scientists” (This article was about the possible connection between disruption to right whale migration patterns by shipping routes and military sonar testing.)

· “Winds delay Pluto mission launch” (This article was about the unmanned U.S. spacecraft soon to be sent on a nine-year voyage to Pluto.)

Below are some examples of how each could be used to teach about the nature of science.

· Scientists gather data under controlled conditions. Claims about the effectiveness of COLD-fX are based on controlled clinical trials in Canada and the US. In the Canadian trials, COLD-fX dramatically reduced the incidence and frequency of recurrent colds. The American results showed that COLD-fX dramatically reduced respiratory infections in elderly patients.

· Scientists generally agree on what is a valid investigation, but there is no fixed set of steps that scientists always follow. Scientists agree that testing new drugs such as COLD-fX should involve double-blind testing, where neither the subject nor the experimenter knows which substance is the drug and which is the placebo. Students could be asked to design and participate in a double-blind study themselves (for example, which of three unknown cleaning products works the best).

· Science produces knowledge by making observations of phenomena and inventing theoretical explanations to make sense of them. Right whale migration patterns have been disrupted and scientists are trying to explain why.

· Theoretical explanations should use or be consistent with currently accepted scientific principles. Current scientific knowledge about the effects of sonar transmissions and ship movements on aquatic life will inform an explanation incorporating these two factors.

· Theoretical explanations should have predictive power and should fit both known observations and additional observations not used in formulating the theories. One test for a sonar/shipping explanation for disruption to whale migration could be to stop the sonar transmissions and change the shipping lanes and monitor the effects. The related prediction would be that, once the effects of these two factors are eliminated, the whales will gradually return to their traditional patterns.

· Scientists resolve the validity of scientific claims by referring to observations of phenomena. Pluto raises many questions among space scientists because of its distance and anomalous characteristics; for example, Pluto resembles neither the rocky inner planets nor the outer gas giants. The Pluto space probe has the potential to make observations that may help answer many questions.

A final word: Science, technology and society

When teaching about the nature of science, it is important to keep in mind that science, technology and society are interconnected. For example:

· Social factors influence which scientific research projects get government funding.

· Decisions about science-related social issues are partially informed by scientific knowledge.

· Technological successes, such as more powerful telescopes, advance scientific knowledge.

· Science helps to explain technological failures such as the crash of the Columbia space shuttle.

· Technological innovations, such as the automobile, influence social change (for example, an automobile culture gives rise to freeways, service stations and suburban shopping malls and fast food outlets).

· A technological link to the testing of three white mystery powders relates to the importance, synthesis and use of indicators in chemistry in general (students can actually make and use their own red cabbage solution indicator to distinguish acids from bases).

· A social link to the story of Fleming and penicillin relates to how, for centuries prior to Fleming’s “discovery,” indigenous people in North America made and applied a paste of mouldy corn to prevent the infection of wounds. Students could discuss the role of social factors in the recognition of what constitutes a scientific discovery.

Often, then, an authentic portrayal of NOS can be extended to include investigation and discussion of technological and societal links. Important for teachers is that students understand what is called science, how science happens and the degree of trust we should place in scientific knowledge. This understanding will assist students to know the world and their place within it, to ask important questions about the world and to think critically about how the world should be.

References

American Association for the Advancement of Science (AAAS). 1989. Science for All Americans. Project 2061. New York: Oxford University Press. Also available at www.project2061.org/publications/sfaa/online/chap1.htm (accessed September 15, 2006).

Collins, S., J. Osborne, M. Ratcliffe, R. Millar and R. Duschl. 2001. “What ‘Ideas-About Science’ Should Be Taught in School Science? A Delphi Study of the Expert Community.” Paper presented at the annual conference of the National Association for Research in Science Teaching, St. Louis, Mo.

Gustafson, B., and D. MacDonald. 2005. A Conceptual Approach to Teaching Children About Science, Technology, and Society. Edmonton, Alta.: Ripon Press.

Norris, S., and L. Phillips. 2003. “How Literacy in its Fundamental Sense Is Central to Scientific Literacy.” Science Education 87, no. 2: 224–40.

Dougal MacDonald and Brenda Gustafson are with the faculty of education (elementary science), the University of Alberta.