IA & EE guides

The IB Physics IA, step by step

On the current Physics course (first exams 2025) the IA is a scientific investigation into a research question you write yourself. It is worth 20% of your grade at SL and HL. This guide covers how it is marked, how to choose a question, what group work is allowed, and how to structure the report.

20% of your grade
About 10 hours
3,000 words max
24 marks
Small-group work allowed

The four criteria, in plain words

Our summaries. Half of all the marks are for the last two criteria, so the thinking after the experiment matters as much as the experiment.

Criterion	Marks	What it rewards, in plain words
Research design	6	A focused research question and a method that can actually answer it: variables identified and controlled, and enough data over a sensible range.
Data analysis	6	Processing your raw data correctly, with uncertainties carried through, and graphs that show what the data says.
Conclusion	6	An answer to your question that your analysis supports, compared with accepted physics.
Evaluation	6	The real weaknesses of your method, how big their effect was, and realistic improvements.

Group work: what is allowed

You may work in a small group and share a similar method.
Each student must change a different independent or dependent variable.
Your data must be your own, and you write and submit your own report. There are no group reports.

Choosing a research question

Pick a relationship, not a topic"How does the length of a pendulum affect its period?" names two variables you can measure.
Choose something you can vary over a wide rangeAt least five values, repeated, gives the analysis something to work with.
Check the theory existsYour conclusion is compared with accepted physics, so pick a relationship you can predict.
Make it a little unusualA twist on a standard experiment (a different material, range or setting) shows independent thinking.

Ideas to start from

How the drop height of a ball changes its bounce height, for different ball materials.
How the temperature of a wire changes its resistance.
How the mass on a spring changes its period of oscillation, and where the simple model breaks down.
How the angle of a ramp changes the speed of a rolling cylinder, solid or hollow.
How water depth changes the speed of waves in a tray.

A sample outline

Research question and backgroundThe question, the physics behind it and your prediction.
MethodVariables, apparatus, procedure, safety, and how you reduced uncertainty.
AnalysisProcessed data with uncertainties, graphs and the gradient or fit that answers the question.
Conclusion and evaluationYour answer compared with theory, the weaknesses that mattered, and improvements.

Common mistakes that cost marks

Too few data points or too narrow a range to show a trend.
Uncertainties calculated once and then ignored in the graph and conclusion.
Evaluation listing "human error" instead of naming specific, measurable weaknesses.
A conclusion that claims more than the data shows.
Going over 3,000 words.

Our promise

We teach. We never write it for you.

This guide explains how the work is assessed and how to plan it. We never write, edit or rewrite any part of a student's IA or EE, and nor should anyone else: the IB treats work produced or heavily edited by someone else (a person or an AI tool) as not your own. If you use an AI tool for ideas or checking, say so and cite it, as your school will ask.

Learn the physics properly

Photon Physics guide

All 24 topics of the current course, plus a Tools and inquiry section with a worked mini-investigation from research question to processing.

See the Physics guidebook

Draft Coach feedback on IA drafts is coming in 2027.

Written by Ejaz Ahmad, IB teacher since 2015. Checked against the IB's published guide, October 2026. Photon Resources is independent of the IB.