IB Physics Extended Essay Topics: What Makes a Good One?

A good topic is narrow enough to investigate properly in 4,000 words, involves a variable you can actually measure or model, and connects to physics you understand deeply — not just something that sounds impressive. The strongest essays start from a genuine question, like 'how does X affect Y?', not a broad theme.

Start broad, then keep asking 'what specifically am I measuring?' until you land on one variable. Instead of 'sound waves', ask how tube length affects resonant frequency in an open pipe. Instead of 'friction', ask how surface roughness affects the coefficient of kinetic friction for a specific material pair.

Yes, but be careful — topics like black holes or quantum tunnelling are popular and often end up descriptive rather than analytical, which caps the mark under Criterion C (Analysis). Examiners consistently note these essays as some of the hardest to get above a 4/6 for engagement, because the data is usually secondary, not collected by you.

Avoid topics with no way to collect original data (most quantum mechanics and general relativity ideas), topics that are really engineering design projects rather than physics investigations, and anything requiring lab access you don't actually have. A student's biggest mistake is choosing a topic that sounds sophisticated but can't be tested at Diploma level.

A strong RQ names the independent variable, the dependent variable, and the specific system being tested — for example, 'How does the length of a conical pendulum's string affect its period of oscillation at a fixed angle?' Vague RQs like 'What affects pendulum motion?' can't be answered precisely, and that costs marks under Criterion A (Focus and Method).

Methods that let you repeat trials, vary one variable at a time, and quantify uncertainty work best — think five or more independent variable values, three-plus repeats each, and a stated instrument uncertainty for every measurement. According to the IB's Extended Essay guide, Criterion B (Knowledge and Understanding) and C (Analysis) together carry more than half the marks, so weak data collection undermines everything after it.

The IB's absolute limit is 4,000 words, and examiners stop reading (and marking) beyond that. Most successful physics EEs run 3,200–3,800 words, with roughly a third on method and raw data, a third on processed data and analysis, and the rest split across introduction, evaluation and conclusion.

It's marked out of 34 against five criteria: Focus and Method, Knowledge and Understanding, Critical Thinking, Presentation, and Engagement — the same criteria used across all EE subjects, applied by a subject-specific examiner. Critical Thinking alone is worth 12 marks, more than a third of the total, which is why analysis quality matters more than data quantity.

Extended Essays across all subjects are graded A to E based on the total mark out of 34, and this combines with your Theory of Knowledge grade for up to 3 bonus points toward your Diploma total. A typical A-grade physics EE scores around 28-34, while a C sits roughly in the high teens to low twenties — exact boundaries are set each session by the IB.

Yes — a theoretical or modelling-based EE is allowed, using simulations, published datasets, or mathematical derivation instead of hands-on data collection. But it needs the same rigour: your own calculations, your own critical evaluation of assumptions, and clear original analysis, not a summary of someone else's paper.

Choose physics only if you genuinely enjoy quantitative problem-solving and are comfortable designing an experiment or model from scratch — it's one of the more demanding EE subjects to score highly in because Criterion C rewards deep uncertainty and error analysis. If your child prefers essay-based argument over calculation, a humanities or interdisciplinary EE is usually the better fit.

Physics EEs aren't inherently harder to write, but they're harder to score a 6 on Criterion C because examiners expect genuine quantitative analysis — uncertainty propagation, graph linearisation, comparison to accepted values — not just a well-argued narrative. Weaker physics EEs often read like lab reports rather than research, which caps the final grade around a C.

No — every IB school assigns a supervisor who gives up to roughly three to five hours of formal contact time across the process, per IB guidance, which is enough if your child starts early and comes prepared with data. What usually costs students marks isn't lack of support; it's starting the topic search too late in Year 12.