IB Physics SL Extended Essay Example

Consider narrowing the question further by specifying the motor setup and operating conditions, such as the load and supply condition. That would make the investigation more precise and would better delimit what counts as a valid change in power.

The research question is clearly stated and immediately identifies both the independent and dependent variables. This makes the investigation’s purpose easy to follow and gives the rest of the essay a clear organising thread.

The method is introduced here, but the sentence is very dense. The student could separate the experimental aim, the simulation aim, and the reason for using two models into shorter sentences so the investigative logic is easier to track.

The introduction establishes a relevant physics context and explains why the topic matters beyond the experiment itself. This helps the reader understand the investigation as a focused application of core electromagnetism ideas.

The background stays on topic and avoids drifting into unrelated electromagnetism content. That focus supports the criterion because the theory is being used to frame the specific motor investigation rather than to showcase general knowledge.

This is a useful principle, but the explanation would be stronger if it connected directly to the coil geometry in the student’s motor. As written, the reader is told the rule, but not fully shown how it governs the torque on the actual apparatus.

The student demonstrates solid subject knowledge by identifying the major motor components and explaining how they work together. This is effective because it turns background theory into a mechanism that can later be connected to the experiment.

The notation is mostly appropriate, but the definition of units for $K_b$ is unclear and seems malformed in transcription. The student should recheck every variable definition for exact unit consistency, since precise notation is essential in a physics investigation.

This statement is physically incorrect for a voltage-driven DC motor in steady state: increasing load torque would normally reduce rotational speed. The student should correct this relationship and revise the explanation that follows so the causal chain matches the motor model.

This fit is not physically justified for a monotonic power trend, and the huge parameter uncertainties shown nearby suggest the model is unstable. The student should not use fit quality alone to claim physical validity; a model needs to be appropriate to the behaviour being studied.

The student does a good job making the analytical method transparent by naming the software and explaining why a fit was chosen. That transparency helps the reader assess the analysis rather than simply accepting a graph at face value.

What evidence shows that this effect is distinct from the stronger claim of magnetic saturation? The student’s discussion would be more convincing if it separated these mechanisms instead of treating them as overlapping explanations.

Comparing horizontal-scaling constants is not a robust way to judge which model best represents the physics of the experiment. The student should compare models using physically meaningful criteria, such as residual patterns, parameter uncertainty, and how well each model explains the measured trend.

The conclusion goes beyond what the data securely establish, because saturation was not independently measured and other mechanisms were not ruled out quantitatively. The student should phrase this more cautiously as a likely explanation rather than a confirmed result.

This is a strong evaluative observation because it acknowledges the limits of the data rather than overclaiming from the graph. That caution improves the argument’s credibility and shows the student can distinguish trend from proof.

The report follows a clear extended-essay structure, and the contents page helps the reader navigate from theory to method, analysis, and evaluation. This supports coherence and makes the document easy to audit against the research question.

The student could make section titles and sub-sections more consistent in numbering and punctuation across the report. A cleaner hierarchy would make it easier to compare the written method with the data and analysis that follow.

Including apparatus photographs strengthens communication because the reader can see key construction choices, not just read about them. That improves reproducibility and makes the method more concrete.

The graph is central to the analysis, so it needs especially clear axis labelling and legend choices. The student should check that every axis and unit matches the quantity being plotted, because any inconsistency here weakens interpretability.

Bringing all three theoretical curves together with the experimental data is an effective presentation choice. It allows direct comparison and makes the discussion of differences much easier to follow.