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VICPhysicsQuick questions
Unit 4: How have new ideas and ways of thinking developed our understanding of the physical world?
Quick questions on Practical investigation: design, uncertainty and communication (VCE Physics Unit 4 AoS 3)
15short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is independent variable?Show answer
The variable you deliberately change. Choose a range of at least 5 values, with sensible spacing.
What is dependent variable?Show answer
The variable you measure in response. The DV depends on the IV.
What is controlled variables?Show answer
Variables that could affect the DV but which you hold constant. List them explicitly.
What is schematic / labelled diagram?Show answer
A clear diagram of the setup is essential. Label all equipment, distances, and measurement points.
What is step-by-step procedure?Show answer
Sufficient detail that another student could replicate the investigation. Include:
What is risk assessment?Show answer
Identify hazards (heat, sharp edges, electrical, optical) and the mitigation for each (safety glasses, low-voltage supply, no looking at laser beam).
What is justification?Show answer
For each design choice, justify why. Why this range? Why this number of repeats?
What is addition / subtraction?Show answer
Add absolute uncertainties.
What is multiplication / division?Show answer
Add fractional (or percentage) uncertainties.
What is powers?Show answer
Multiply fractional uncertainty by the power.
What is constants?Show answer
Constants do not contribute uncertainty. $z = k x$ has $\Delta z / z = \Delta x / x$.
What is linearisation?Show answer
If the predicted relationship is non-linear, transform the data to produce a linear plot.
What is best-fit line?Show answer
Draw a line through the data using a line of best fit. The gradient and intercept (with uncertainties) come from the slope and y-intercept of this line.
What is maximum and minimum gradient lines?Show answer
To estimate the uncertainty in the gradient, draw two further lines: one with the maximum reasonable slope through the data with uncertainty bars, and one with the minimum reasonable slope. The half-range of these slopes is the uncertainty in the gradient.
What is compare to theory?Show answer
State the theoretical prediction (e.g. $g = 4 \pi^2 / \text{gradient}$ from a pendulum). Calculate the experimental value from the measured gradient.