Nature of science for teaching

Nature of Science for Teaching David Geelan

What is science?
There are at least four parts to a definition:
A set of methods and standards for creating and testing knowledge claims
A body of knowledge that has been created by scientists and has (so far) succeeded in passing such testing
The domain of human knowledge that deals with the natural world
A world view or set of values – a commitment to the methods and standards of science in their appropriate domain

Teaching Science
When we teach science we are involved in developing in students the knowledge, skills and attitudes that allow them to engage with science
Teaching science is much more than transmitting content knowledge

Induction and Deduction
In logic, ‘induction’ describes the building up of broad, general laws or theories from looking at individual cases and examples
‘ Deduction’ describes the reverse process of predicting individual cases from the broad general rules

Inductivism
The theory of natural science that began with Francis Bacon
Inductivism is the belief that scientific theories arise through repeated observations of the natural world
Sufficient careful observations of the same phenomenon allow scientists to propose a general rule

Example of Inductivism
A simple example of inductive reasoning is the statement ‘All swans are white’ – sufficient experiences of seeing white swans in Europe might allow this to be stated as a general rule – but when you get to Australia and see black swans, the rule is no longer considered valid

Critiques of Inductivism
There is a logical problem with inductivism: where does the ‘principle of induction’ (the idea that sufficient observations allow us to state a law’) come from? It’s not out there in the natural world, so the only way we could find it is… by induction!
This is circular reasoning

Critiques of Inductivism
A number of philosophers of science, including Popper and Kuhn, have described alternative ways of thinking about science to inductivism

Scientific Methods
We shouldn’t teach our students about ‘ the scientific method’ – science is not that simple – but about ‘scientific methods’
Most scientific methods arise out of inductivism, or its logical equivalent, ‘verificationism’
That is, scientists propose an hypothesis and then seek evidence to verify it

Scientific Methods
(read the relevant literature to know what has been done before)
Propose an hypothesis
Determine what kind of evidence would verify (support) or falsify the hypothesis
Gather the evidence (dependent, independent and controlled variables)
Analyse it to test whether it supports the hypothesis
Critically evaluate your methods and actions

Scientists and Students
What high school students are doing is both similar and different to what scientists are doing:
Similarities:
Both testing knowledge claims (ideally through experiment)
Both using scientific methods

Scientists and Students
Differences
Scientists are creating new knowledge
Students are creating – for themselves, in their own minds – new understandings of existing knowledge

Sources of Evidence for Knowledge Claims
Authority
Experiment
Experience (informal experiment)

Science Education
Unless we allow students to gather evidence in the laboratory with which to test knowledge claims, their only source of evidence is our authority
That would be what’s called ‘indoctrination’ 

Conceptual Change Theory David Geelan

Conceptual Change
In most cases, particularly in high school, students come to the science classroom with an existing ‘theory’ about a phenomenon
This theory might come from their earlier science education, but is more likely to come from their experience of the world

Conceptual Change
This means that teaching a new science concept is not simply a matter of transferring the science into an empty vessel
What is most often occurring in science education (if it’s successful) is a conceptual change from one concept to another

Misconceptions/whatever
In science education, students’ existing beliefs and theories have been described as: misconceptions, preconceptions, children’s science, alternative conceptions, naïve conceptions…

Conceptual Change
This change is unlikely to occur based only on our authority – students need evidence from the physical world
That evidence is obtained in the lab or demo
But for the evidence to actually mean anything, the student needs to know in very clear terms what a particular result implies

Conceptual Change
To do that, the new concept that we are offering – the scientific concept – has to be seen as:
intelligible
plausible
fruitful
(Posner, Strike, Hewson & Gertzog)

Predict, Observe, Explain
One strategy for allowing students to compare their existing concepts to the scientific ones is a ‘predict, observe, explain’ activity
Students are asked to predict the result of an experiment. They will do this based on their existing knowledge

Predict, Observe, Explain
They then observe the experiment, and see whether their prediction was supported or falsified, and are asked to explain their observation
With a well designed experiment, the scientific concept will explain the results better (more fully and clearly) than the naïve conception that the students hold

Evidence
There are a variety of other strategies that teachers can use to allow students to gather evidence with which to test both their existing ways of understanding the world and the scientific ways that are being offered to them

Conclusion
The important point is that any science education program worthy of the name gives students scientific, empirical evidence, not just appeal to authority
We recommend that 20-25% of all science classes have a lab or demonstration component

Nature of science for teaching

by David Geelan

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