How Do You Write a Strong MYP Chemistry Lab Report / Investigation?

I've marked hundreds of these, and the reports that score 7-8 in each strand all do the same thing: they never describe an experiment for its own sake, they use it to answer a question.

5-step structure:

1. Research question + hypothesis — one sentence, testable, with scientific reasoning (Criterion A)
2. Variables table — independent, dependent, at least 3 controlled
3. Method — numbered steps, enough detail for someone else to repeat it exactly
4. Data + processing — raw table, then a processed table (means, uncertainty), then a graph
5. Conclusion + evaluation — answer the question, compare to your hypothesis, name a real limitation and a realistic improvement

Quick tip: write your research question LAST, after you know what data you actually collected — students who write it first often end up with a question their method can't actually answer.

According to the IB's MYP: Sciences guide, each criterion has its own strand descriptors at four achievement levels (1-2, 3-4, 5-6, 7-8), and your teacher awards a level for each strand then sums them. A report missing Criterion D — the section on environmental, ethical or safety implications — automatically caps your overall mark, even if the data and analysis are excellent.

Worked example: Investigating how temperature affects reaction rate between sodium thiosulfate and hydrochloric acid?

Weak hypothesis: "The reaction will go faster at higher temperature."

Strong hypothesis: "As temperature increases, the rate of reaction will increase because particles gain kinetic energy, collide more frequently and with greater force, increasing the proportion of collisions that exceed the activation energy (collision theory)."

The second version earns marks in Criterion A because it names the mechanism, not just the trend.

Common mistake: students write the method as a narrative ("First I got the equipment, then I mixed the chemicals...") instead of numbered, replicable steps. Examiners specifically check for repeatability — if a step says "heat until it changes colour" without a target temperature or time, that's a gap in Criterion B.

Quick tip: always show your raw, unprocessed data in one table and your processed data (means, ranges, uncertainty) in a second, separate table. Combining them in one messy table is one of the most common reasons Criterion C marks drop.

Worked example — calculating rate of reaction:

If a reaction took 42 seconds for a fixed amount of product to form, rate = $1/t=1/42=0.024{\text{s}}^{-1}$.

Show this calculation once, in full, then apply the same formula silently to the rest of your table — examiners want to see you understand the method, not forty repeated identical calculations.

Don't just restate the hypothesis as "my hypothesis was correct." Reference specific numbers from your results table, and if the trend wasn't perfectly linear or one point was anomalous, say so here rather than ignoring it — that honesty is part of what Criterion C rewards.

Checklist for a Criterion C evaluation:

1. Name one real limitation specific to YOUR method (not generic "human error")
2. Explain how it would have affected your results (over- or under-estimate?)
3. Suggest one realistic, specific improvement (a data logger instead of a stopwatch, not just "be more careful")
4. Comment on how strong the trend/correlation actually was, referencing your graph

In my experience marking these year after year, Criterion D is the one students forget most often — it's easy to focus on data and forget the report also needs a short paragraph on safety precautions taken, or the environmental impact of disposing of chemicals used, tied to your specific experiment rather than generic statements.

According to the IB's MYP: Sciences guide, on-screen eAssessment papers include a scientific investigation component that draws directly on the same command terms and criteria used in classwork — so the habits you build on regular lab reports (clear variables, processed data, honest evaluation) transfer straight into exam performance.

On revisionprep.com, the MYP Chemistry Revision Notes and Topical Worksheets are built around exactly this kind of practice — sample data sets and command-term-based questions so you can rehearse Criterion C processing and evaluation without needing to run a new experiment every time.

You don't need a chemistry background to help meaningfully. Sit with the criteria descriptors (available from the school or IB) and ask your child to point to where in their own report each strand is addressed — it turns editing into self-checking, which is the actual skill being assessed.