IB Chemistry IA: how to choose a strong research question

The Internal Assessment is worth a large share of your IB Chemistry grade, and it is one of the few parts you fully control before the exam. Most of the marks are decided the moment you choose your research question. Get that right and the write up almost writes itself. Get it wrong and no amount of effort fully recovers it.

Start from something you can measure

A strong IA has one clear independent variable that you change and one dependent variable that you measure, with everything else controlled. Before you fall in love with a topic, ask a simple question: can I measure the outcome with the equipment I actually have, and can I change the input in at least five steps? If the answer is no, the idea will not give you enough data to analyze.

What makes a research question strong

A good research question is specific, measurable and focused on a relationship. "How does temperature affect reaction rate" is too vague. "How does temperature, from 20 to 60 degrees Celsius in 10 degree steps, affect the rate of reaction between sodium thiosulfate and hydrochloric acid, measured by the time to obscure a cross" is something you can plan, run and analyze. The detail is not decoration, it is what makes the investigation gradeable.

Plan for enough data

Aim for at least five values of your independent variable and several repeats of each, so you can show uncertainty and spot anomalies. Thin data is the most common reason an IA stalls at a middling grade. Plan your repeats and your uncertainties before you start, not after.

Where students lose marks

The usual losses are not about chemistry. They are about ignoring uncertainties, skipping the link back to chemical theory, and weak evaluation. The evaluation section is where strong students pull ahead: name the specific weaknesses of your method, explain how each one affected the result, and propose realistic improvements. Examiners reward honest, specific reflection far more than a perfect set of results.

A workable timeline

Lock your research question early, run a quick pilot to check the method gives usable data, then collect your full data set, and leave real time for analysis and evaluation. The write up takes longer than people expect, so do not let data collection eat all your time.

The IA rewards careful planning more than luck. If you want feedback on your research question and write up from a certified IB Chemistry teacher, take a look at our IB Chemistry course.