Section 3 looks like a science exam and frightens people accordingly. It is really a reasoning exam that hands you the science you need. Here is how to work from the information given, the maths that quietly decides your score, and how to practise each subject.
The fear most people bring to GAMSAT Section 3 is that they will be quizzed on every fact from first-year science. They will not. The section is built around stimuli that give you the law, the formula, the data table or the experiment, and then ask whether you can reason with it. Knowing the background helps you move faster and avoid silly errors, but the marks are for the thinking, not the memory. Once that clicks, the section becomes a comprehension-and-logic exercise dressed in a lab coat.
Original biology, chemistry and physics questions, plus a dedicated maths-skills set, all text and data based, with worked explanations and a breakdown by topic.
Section 3, Reasoning in Biological and Physical Sciences, is the largest section: around 75 questions in roughly 150 minutes, about two minutes each. The assumed background is first-year university biology and chemistry and Year 12 physics, weighted roughly 40% biology, 40% chemistry and 20% physics. Most questions are stimulus-driven: a short passage sets up a scenario, gives you a relationship or a data set, and the questions test whether you can apply it, interpret it or predict what a change would do.
If there is one underrated lever in Section 3, it is mental maths. A large share of questions ride on quick, calculator-free calculation: scientific notation, powers and logarithms, ratios and proportion, unit conversion, rearranging formulae and estimation. When that arithmetic is slow or shaky, it does not just cost the pure-calculation questions; it drains the time and confidence you needed for the reasoning. Treat the maths as a skill to drill on its own until it is automatic. My free S3 tool has a dedicated Maths and data skills set for exactly this.
Build one reliable habit for every stimulus: extract first, then apply. Read the passage and pull out the rule or data it is handing you, underlining the relationship in plain terms ("rate goes as one over the square root of mass", "pressure equals density times g times depth"). Only then look at what the question wants and apply the rule. Most Section 3 errors come from jumping to the options before you have nailed down what the stimulus actually gave you.
Biology: the reasoning often hangs on a process or a feedback loop. Get fluent with the recurring systems, membranes and transport, enzymes and metabolism, genetics, the nervous and cardiovascular systems, so that when a stimulus describes one, you can predict what a change will do rather than recalling a fact.
Chemistry: a handful of frameworks recur constantly, Le Chatelier and equilibrium, acids and bases and pH, reaction energetics, and oxidation level. Recognise them on sight and you can reason through unfamiliar contexts. Organic questions frequently test functional-group logic and interpreting data such as an IR table rather than drawing mechanisms.
Physics: the maths is closer to Year 12, and the questions usually give you the equations. The skill is choosing the right relationship, handling units and powers of ten cleanly, and estimating. Practise the staples, the kinematics equations, work and power, circuits and fluids.
Trying to recall content instead of reasoning from the stimulus the question already gave you. Reaching for full calculation when an estimate would eliminate three options and save a minute. Slipping on units and powers of ten, the most common and most expensive error in the section. And answering the question you expected after a dense stem instead of the one actually asked.
No. It is mostly reasoning from information the question supplies. Stems usually give you the law, formula or data, then test whether you can apply it. Recall alone rarely earns the mark.
First-year university biology and chemistry, and Year 12 physics. The depth is modest; the reasoning and the speed are the real challenge.
Both are reasoning tests, but Section 3 reasons from scientific data, experiments and formulae, while Section 1 reasons from humanities and social-science material.