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Science as argument

Scientific arguments allow scientists to debate an existing idea, using the evidence for or against it.

To be accepted, a theory or explanation must stand the test of this debate and provide sufficient evidence that supports the idea.

The purpose of science is to ensure that theories about the world we live in are supported by sufficient evidence.

Sometimes a scientific idea precedes any evidence relevant to it; at other times, the evidence helps to inspire the idea.

Teachers need to build students’ understanding that science is based on argument through which rival hypotheses are investigated to present evidence about competing factual claims. Sometimes this argument takes the form of a debate.

What is science as argument?

Scientific idea + Expectations + Observations = Scientific argument

Scientific arguments are logical descriptions of a scientific idea and the evidence for or against it.

The matrix for science as argument provides a progression for developing students’ ability to engage in scientific debate and argument, which must be built over time.

An argument often uses a series of steps to identify, analyse, and evaluate the topic or issue:

  1. A main idea is identified as a statement.
  2. The statement is identified as true or false.
  3. Supporting evidence, justification or examples are found (premises) that connect to the statement.
  4. There will usually be at least two reasons in the argument that follow this sequence.
  5. A concluding statement evaluates or summarises the evidence.

NoS elements of science as argument

Science as argument links to the Participating and contributing, and Communicating in science elements of the NoS strand.

Developing science as argument

The purpose of argument in science teaching is to persuade students to seek evidence and reasons for their ideas, and to take evidence seriously as a guide for belief and action.

The success of scientific argument depends on making a clear distinction between hypothesis and evidence. Students do this by investigating alternative hypotheses and engaging in evidence-based argument about the competing factual claims.

The final argument will consist of a connected series of statements that establish a position on an issue, and imply a response to one or more other positions.

To build their ability to address science as argument, students need to be able to distinguish:

  • fact from opinion
  • bias in evidence
  • inference from assumptions.

They also need to have a well-developed reasoning ability so that they do not make assumptions without considering the evidence in depth.

Fact versus opinion

To begin to build understanding about science as argument, students need to be able to distinguish fact from opinion.

Opinions are often personal and based on feelings or beliefs, or on the idea that an event might in the future. Other people may disagree with the idea.

There are two main ways of verifying opinions:

  • social validation – meaning is socially constructed and agreed. There is general agreement on what has actually happened or existed in the past, or based on the experience of many people; very few people will disagree with it.
  • empirical validation – meaning is confirmed by measuring and testing.

Facts can be verified by evidence, which is empirical whenever possible, and confirmed by investigations and observations.


In this activity, students decide whether statements about seagulls are fact or opinion, discuss what assumptions they made in making their decision and describe the evidence they based their decision on.

Students read a short article about bananas and highlight the statements that are fact or opinion. Students are given a list of statements for and against the use of cellphones and are asked to decide which statements are fact and which are not.

Recognising bias as part of argument

Students also need to learn how to judge for bias.

Bias can usually be recognised by the use of:

  • emotive words
  • opinion presented as fact
  • irrelevant statements that divert attention from the issue
  • generalisations that provide a very broad interpretation of the issue
  • exaggeration – descriptions that go beyond the limits of the truth.

The following questions can help build students’ ability to recognise bias.

  • Is this information intended to persuade?
  • Does anything seem wrong? Are there any gaps? Is any information missing?
  • What is wrong with the underlying information?
  • Does it have:
    • misinformation?
    • faulty logic?
    • weak references?
    • attacks?
  • How do the types of bias affect the meaning of the text?
  • Is there any visual bias in the article?

How to test the validity of a scientific argument

Scientific arguments can generally be tested for their validity by asking the following questions:

  • What is the idea?
  • If this idea were true, what would we expect to observe in a given situation?
  • Does this expectation actually happen?
  • If it happens, how does it affect the likelihood that the idea is accurate or inaccurate?


A number of graphic organisers are available to support students in developing capability in scientific argument.

The following resource provides a template for applying critical thinking to a scientific debate – in this case, genetic modification.

What students need to be able to do

Level 6: Participating and contributing

Students need to be able to:

  • distinguish between statements that are scientific data and those that are inferred as part of an explanation
  • explain how they made this decision.

Level 7–8: Participating and contributing

Students need to be able to judge the quality of their own and others’ arguments, based on the critical evaluation of scientific evidence.

Last updated May 6, 2013