IB Physics SL Extended Essay Example

The research question is stated clearly and is easy to follow. It identifies a measurable relationship and a specific location, which gives the investigation a clear direction from the outset.

The wording is still too broad because "orientation" could mean tilt, azimuth, or both. The student should define exactly which angle is varied and under what date/time conditions, so the investigation has one precise independent variable.

The student has narrowed the variable here to inclination, but this does not fully match the earlier use of "orientation." The method would be stronger if the research question, variable definition, and later analysis all used the same term consistently.

This control is not realistic enough to support a reliable optimum-angle claim. The sun is not directly overhead at midday in Barcelona, so the student should specify the actual time window and control or measure solar elevation rather than assume overhead sun.

Consider randomising the order of the angles instead of moving steadily upward. That would reduce the effect of heating and the changing position of the Sun, both of which could otherwise bias later readings.

Repeating measurements is a sensible step, but the student would improve the method further by stating how the readings were timed and whether the panel was allowed to stabilise at each angle before recording values. That would make the repeats more comparable.

This definition confuses the photovoltaic process with the external photoelectric effect. The student should explain that PV cells create a potential difference in a semiconductor junction, rather than saying photons are converted into electrons.

The student should replace this with a more accurate explanation of the photovoltaic effect. Using the wrong effect weakens the physics background and leads to later misunderstandings in the argument.

The explanation is physically incorrect. Perpendicular incidence increases the projected irradiance on the panel surface, not because the Sun is closer. The student should link the maximum output to incident angle and effective area, not distance.

This is a reasonable control, but the student should be more precise about what is being controlled: material, condition, and electrical rating. That would show stronger understanding of why cell variation changes output.

At this point the table shows a power value that is inconsistent with the stated current and voltage values. The student should verify the calculation and show the working using consistent units, otherwise the data cannot be trusted.

The units here should be checked carefully, because the later power values do not match the stated current and voltage units. Correct unit consistency is essential in physics, since incorrect units make the calculations unreliable.

The student shows good awareness that uncertainty is not just random scatter. Including error bars is a useful step because it signals an attempt to evaluate the reliability of the measurements rather than presenting the graph as exact.

The maximum is asserted without showing the calculation, and it does not obviously match the raw data, where the highest tabulated power appears at 50°. The student should explain how the vertex was found and reconcile it with the measured data before drawing a conclusion.

This conclusion overstates reliability because the comparison rests on questionable geometry and incompatible assumptions about the secondary data. A close percentage difference alone is not enough; the student should evaluate whether the comparison is methodologically valid in the first place.

The uncertainty treatment is too narrow because it only uses angle uncertainty and ignores the much larger systematic issues in irradiance, solar position, temperature, and load dependence. The student should separate random uncertainty from systematic error and discuss both explicitly.

What would happen to the calculated optimum if the Sun’s elevation were measured directly for each reading instead of assumed to be overhead? Thinking through that change would help the student judge how much of the conclusion depends on the original simplification.

This is a useful improvement idea. The student could make it even stronger by also suggesting a fixed resistive load or full $I$-$V$ curves, since PV power depends strongly on the load and that is a major source of error here.

This contents-page entry should be corrected, because it interrupts navigation and suggests an unresolved reference. The student should check all links or references in the contents list so every section title points correctly.

The report is well signposted with a contents page and clearly separated sections. This helps the reader follow the investigation from introduction through evaluation and supports a logical academic structure.

The student could improve the presentation of the secondary data by summarising the source more explicitly and distinguishing it from the student’s own interpretation. A short caption explaining what the graph shows and why it matters would make the comparison easier to follow.

The data table is clearly labelled and grouped by trial and average, which makes the pattern in the measurements easy to trace. That organisation supports the later graph and analysis well.

The regression equation should be presented with standard decimal notation and proper superscript formatting for $x^2$. The current form makes the graph harder to read and weakens the professionalism of the presentation.

The x-axis label should use the correct degree symbol and a consistent unit format. Clear, standard scientific labelling matters because the graph is part of the evidence used to justify the optimum-angle claim.