ACARA v9 CONTENT DESCRIPTION “construct evidence-based arguments to support conclusions or evaluate claims and consider any ethical issues and cultural protocols associated with using or citing secondary data or information”
Builds on weighing evidence and claims. Now you move from judging the case made by others to constructing your own: choosing the observations and trusted data that support a conclusion, and using outside information honestly and respectfully.
An argument is a conclusion plus its reasons
A strong scientific argument states a conclusion and then gives the evidence that leads to it. The best supports are direct measurements and observations. You can also draw on secondary data, information gathered by others, but only if you cite where it came from and treat it fairly. Statements based on appearance, rumour or feeling do not belong in the case, however reasonable they sound.
Build the case, leave out the weak parts
Your class investigated whether a creek is healthier upstream than downstream, using both your own samples and a council dataset. Decide which statements genuinely support the conclusion and belong in the argument.
Claim: This creek is in better health upstream than downstream.
Your upstream water samples held more dissolved oxygen than the downstream samples on every sampling day.
You counted more living water insects, such as mayfly larvae, in the upstream samples.
The council monitoring dataset, cited in your report, records higher pollution downstream over five years.
The downstream bank just looks messier, so the water there must be worse.
You copied figures from a blog without naming the source or checking how they were measured.
Decide whether each statement is evidence for the claim, or not.
Show your strongest evidence, do not just assert it
An argument lands harder when the reader can see the evidence, not only read that it exists. Your own measurements are the backbone of the case, so present them clearly. View the dissolved-oxygen readings below as a graph and notice how the gap between the two sites becomes something a reader can judge at a glance, rather than a number they must take on trust.
Turn your readings into evidence a reader can see
These are your own dissolved-oxygen measurements, averaged at three points down the creek. Switch between the table, the bar chart and the line graph and see which presents the case most plainly.
Healthy creek water usually holds more dissolved oxygen, so the steady fall from 8.4 down to 3.9 milligrams per litre is direct support for your conclusion. Laid out as bars, the downstream shortfall is impossible to miss, which is exactly what a clear, evidence-based argument needs.
Use outside information with care
Secondary data can make an argument far stronger, but it carries responsibilities. Always name the source so others can check it, and prefer data whose method you can see. Where information or a study site connects to a community, including an Aboriginal or Torres Strait Islander community, seek permission and follow their cultural protocols. Honest, respectful sourcing is part of building a sound case, not an extra afterwards.
How should you handle data tied to a community?
Your strongest evidence comes from long-term records that a local Aboriginal ranger group keeps about the creek and its cultural significance. Choose how to use it and weigh what each choice gains and gives up.
Secondary data is not just numbers; it can belong to people and carry cultural meaning. How you obtain and credit it is an ethical decision, not only a scientific one.
Choose a response to see what is gained and what is given up.
Why this matters
Whether you are persuading a council to protect a waterway or writing up a school report, an argument is only as good as the evidence behind it and the honesty with which it is built. Learning to select strong support, set aside the weak, and credit your sources is a skill you will use far beyond science class.
Quick self-check
1. What makes an argument evidence-based rather than just an opinion?
2. You include a government water-quality dataset to strengthen your argument. What must you do?
3. Which statement would belong in the argument, rather than weaken it?
4. Your data was collected near a site of cultural significance to a local Aboriginal community. The right step is to...
5. A classmate concludes the creek is unsafe everywhere, but only the downstream site was tested. The best fix is to...