Working Scientifically in Biology

In short: Working scientifically in biology means testing a question fairly: write a hypothesis (if, then, because), change one independent variable, measure the dependent variable and control everything else. Repeat trials and use the mean, so the results are valid, reliable and accurate.

Starting point: what you already know

• Independent, dependent and controlled variables from Years 7 to 10 science.
• Drawing tables and line or column graphs.
• Calculating a mean (average): add the values and divide by how many there are.

From question to hypothesis

Every investigation starts with a question that can be tested, like "Does the amount of light change how fast pondweed makes oxygen?"

A hypothesis is a testable prediction with a reason. A good one names both variables:

If light intensity increases, then the rate of oxygen production will increase, because light provides the energy for photosynthesis.

Variables

A control group (or control) is a set-up where the independent variable is not applied, so you have something to compare with. In Mia's story, the tanks with water left to stand are compared with the fresh tap water tanks.

Safe and ethical work

Before any practical, write a risk assessment: the hazard, the risk, and how you will lower it. Biology adds two special areas.

• Living things. Animal research in schools must follow animal ethics rules. Cause the least harm, use the fewest animals and replace animals with models or plants where possible.
• Microbes. Treat every culture as if it could cause disease. Seal agar plates with tape, never open them after incubating and incubate at 25 to 30 degrees, not body temperature.

Showing your data

Put the independent variable on the horizontal axis, label both axes with units and give the graph a title.

First Nations knowledge and science

Aboriginal and Torres Strait Islander peoples have studied Australian plants, animals, seasons and fire for more than 60 000 years. This knowledge was built by careful observation over many generations, which is also what science does.

This knowledge belongs to the communities who hold it. It is called Indigenous Cultural and Intellectual Property (ICIP). When you use it in a project, you should

• use sources that the community has shared publicly or approved,
• name the community or Nation the knowledge comes from,
• ask permission from the right people before using knowledge that is not public, and
• never claim it as your own idea.

Quick summary

• Start with a testable question, then write a hypothesis with "if, then, because".
• Change one independent variable, measure the dependent variable and control everything else.
• Valid means a fair test, reliable means repeatable, accurate means close to the true value.
• Repeat trials and use the mean. Check outliers instead of ignoring them.
• Choose the right graph: line for continuous data, column for categories.
• First Nations knowledge is ICIP: use approved sources, name the community and ask permission.

Quiz