The assumption students don’t realise they’re making
Every Physics question comes with assumptions built in.
About direction.
About what can be ignored.
About what matters and what doesn’t.
The problem is that many students make those assumptions silently. They think them through, apply them mentally, and then skip straight to the calculation.
In VCE Physics, unstated assumptions are often indistinguishable from incorrect reasoning.
Physics rewards clarity, not mind-reading
Examiners can only mark what is on the page.
If a student assumes air resistance is negligible, that assumption needs to be reflected in the working. If a reference direction is chosen, it needs to be clear and consistent. If an object is treated as a point mass, the reasoning should align with that choice.
When assumptions are invisible, errors look careless rather than considered.
Why direction is the most dangerous hidden assumption
Direction is one of the most common places marks are lost.
Students often switch directions halfway through a solution without realising it. Velocity is treated as positive in one step and negative in the next. Acceleration changes sign without explanation.
The mathematics may still work, but the physics becomes incoherent.
Strong students commit to a direction early and stick to it. The direction itself does not matter. Consistency does.
“Negligible” is not a casual word in Physics
Students frequently ignore factors like friction, air resistance, or energy loss because they are used to doing so.
Sometimes that is appropriate. Sometimes it is not.
What matters is whether the question allows it.
If a factor is ignored without justification, the solution can collapse later when results do not match physical expectations. Marks are lost not because the calculation is wrong, but because the model is incomplete.
Ignoring something in Physics is a decision, not a shortcut.
Why unstated assumptions weaken explanations
This issue appears just as often in written explanations as it does in calculations.
Students explain behaviour using correct principles, but their explanation relies on conditions that were never stated. The logic makes sense in their head, but not necessarily on the page.
Physics explanations need to show the conditions under which they are valid. Without that, they sound generic rather than precise.
How assumptions affect data interpretation
When working with data, assumptions still matter.
Students may assume a graph is linear without checking. They may assume a trend continues beyond the measured range. They may assume ideal conditions where the data suggests otherwise.
Strong responses show restraint. They explain what the data supports and stop there.
Assumptions that go beyond the data weaken credibility.
The difference between implied and explicit reasoning
Many capable students believe that stating assumptions explicitly is unnecessary because “it’s obvious”.
In assessment, obvious is not a marking criterion.
Explicit reasoning shows control. It tells the examiner that the student understands not just what happens, but why the chosen model applies.
This is especially important in multi-step questions, where early assumptions affect every step that follows.
What strong Physics students do differently
High-performing students treat assumptions as part of the solution, not background noise.
They decide what can be neglected. They define their directions. They choose their model deliberately. And they make those choices visible through their working and explanations.
Their answers feel stable because every step rests on something solid.
A useful self-check during practice
If a solution relies on something being ignored, idealised, or simplified, ask whether that choice is visible in the answer.
If changing the assumption would change the result, it probably deserves a mention.
This habit alone prevents a large number of avoidable errors.
What this means for Physics preparation
Physics preparation should include practising how to state assumptions cleanly and efficiently.
This does not mean writing long explanations. It means making key decisions clear and consistent. Students who practise this skill find that their working becomes more reliable and their explanations more convincing.
Assumptions stop being a risk and start becoming a strength.
Working with ATAR STAR
ATAR STAR Physics tutoring focuses on helping students make their reasoning explicit.
We work with students on choosing appropriate models, maintaining consistent assumptions, and presenting solutions that show clear physical thinking from start to finish. The aim is not to complicate answers, but to stabilise them.
If Physics marks feel fragile despite solid understanding, hidden assumptions are often the culprit, and that is exactly where ATAR STAR helps students gain control.