MYP Physics: Designing a Physics Investigation (Criterion B)

Criterion B assesses four things: stating a clear problem or research question, writing a testable hypothesis backed by scientific reasoning, identifying and explaining how you'll control variables, and designing a safe, logical, replicable method with the right equipment and enough trials to spot patterns in your data.

Criterion B, Inquiring and designing, is one of four MYP Sciences criteria alongside Knowing and understanding, Processing and evaluating, and Reflecting on the impacts of science. It measures how well you turn a scientific question into a testable, safe, repeatable investigation — not how impressive your final results are.

Criterion B has four strands: (i) explaining the problem or question being tested, (ii) formulating and explaining a testable hypothesis using scientific reasoning, (iii) explaining how variables will be manipulated and how data will be collected, and (iv) designing a logical, safe, complete method with appropriate materials.

A strong hypothesis predicts a specific relationship between two variables and explains why, using physics reasoning — not just 'I think X will happen.' Examiners want the mechanism behind your prediction: link it to a law, formula or concept you've actually studied in class.

Name three variable types clearly: the independent variable you deliberately change, the dependent variable you measure, and controlled variables you keep fixed so they don't distort your result. Strand iii wants you to explain how each is measured or controlled and why that control actually matters.

A level 7–8 method reads like an instruction manual a stranger could follow without asking you a question: numbered steps, exact equipment with a stated range or precision, at least five data points per variable, repeat trials for reliability, and a safety measure relevant to your actual apparatus.

Plan on roughly three working sessions for MYP 4-5: one for background research and drafting the hypothesis, one for identifying variables and writing the method, and one for teacher feedback before you finalise. Some schools compress this into a single lab double period plus homework — ask your teacher which model applies.

In years of marking these, three mistakes repeatedly cap work at level 4: a hypothesis that predicts without explaining the physics behind it, vague variable control like "keep everything else the same" with no specifics named, and a method missing a measurable range or repeat trials.

Criterion B is marked 0–8 using four achievement bands — 1–2, 3–4, 5–6 and 7–8 — each with its own descriptor in the MYP Sciences guide. Your teacher awards one best-fit mark based on which band your work matches most closely across all four strands, not an average of separate strand scores.

Criterion B is worth 8 marks, the same weighting as Criteria A, C and D, giving 32 raw points across a full assessed task. Schools then convert this raw total into the 1–7 grade used on MYP reports, using grade-boundary descriptors set by the school's curriculum team, which vary slightly year to year.

No — related but not equivalent. Criterion B covers only the design stage (question, hypothesis, variables, method), while the DP Physics internal assessment is a full investigation report including data, analysis and evaluation, marked against five separate criteria. According to the IB, first exams for the current DP Physics guide were 2025.

Don't write the hypothesis for them — ask questions instead: "why do you think that will happen?", "what exactly are you keeping the same?", "could someone else follow these steps without you there?" Those three questions target precisely what Criterion B rewards, and they take about ten minutes at the kitchen table.

Look for materials built around the actual four strands, not a generic "scientific method" template: modelled hypotheses that show their reasoning, variable tables like the ones examiners expect, and full sample investigations you can check against the level 7–8 descriptors before submitting your own work.