The research question is sharply defined and situated within a specific context linking refractive index relevance to optics and renewable fuels.

Relevant theoretical frameworks (Snell’s law) and specific boundary conditions (constant temperature and pressure) are cited to justify the investigation’s importance.

The apparatus list and step-by-step method are presented logically, enabling reproducibility with minimal ambiguities.

A clear, testable hypothesis predicting a linear relationship between ethanol concentration and refractive index is articulated.

Some literature references are incomplete, reducing academic rigour.

The table following Snell’s law omits the key equation, hindering reproducibility.

Units for ethanol concentration switch between g/mL and percentages, introducing ambiguity.

The alignment procedure for the laser and phone app lacks detailed, step-by-step instructions.

One method step ends mid-sentence, leaving the incidence-angle rationale unfinished.

Data recording and processing are communicated clearly through well-labelled raw and processed tables, units, and a plotted graph.

The apparatus list includes uncertainty specifications, enhancing transparency.

Data processing steps (degree–minute conversion, averaging) are described in a clear and systematic manner.

Formatting glitches (mis-typed minutes, blank columns) and undefined placeholders reduce precision in data presentation.

Uncertainties are only partially considered; propagation into refractive indices is omitted and systematic error sources (container thickness, dispersion) are not quantified.

Calculation inconsistencies (e.g., incorrect degree–minute conversion, implausibly high n-value for pure ethanol) indicate processing inaccuracies.

Error analysis uses placeholder symbols and lacks full formulas, leading to significant omissions.