MYP Physics: Using Formulae & Rearranging Equations

It's assessed mainly under MYP Sciences Criterion C (Processing and evaluating) and Criterion D (Reflecting on the impacts of science), where you select and manipulate the correct formula, substitute values with correct units, and show working. Command terms like 'calculate', 'determine' and 'deduce' all expect a rearranged, substituted equation with a final answer.

MYP doesn't give you a formula sheet like DP does, so yes — you need core equations memorised: speed = distance/time, density = mass/volume, force = mass × acceleration, work = force × distance, and Ohm's law (V = IR) are the ones tested most often across Years 4-5 units.

The reliable method is: identify what you're solving for, then do the same operation to both sides until that variable stands alone. For F = ma, solving for a means dividing both sides by m, giving a = F/m. Skipping this step and guessing is the single most common exam mistake I see.

Usually it's not a physics problem, it's an algebra habit problem — students substitute numbers into the original equation and then try to rearrange with numbers already in place, which multiplies errors. Rearrange the letters first, then substitute at the very last step. That one change fixes most mistakes I mark.

Always carry units through the whole calculation, not just at the end — if your rearranged formula gives you kg/m³ when you expected m/s, you've made an algebra error, not a units error. Unit-checking is the fastest self-mark technique I teach in Year 4-5 classes.

Substituting means plugging known values straight into a formula that's already solved for the variable you want. Rearranging means algebraically moving terms first, when the unknown isn't isolated. Most Criterion C questions expect both — rearrange first, substitute second — and marking schemes credit each step separately.

Top marks (7-8) under Criterion C require you to select an appropriate formula, apply mathematical and technological skills correctly, and interpret results with correct significant figures and units, according to the MYP Sciences guide's assessment criteria descriptors. A right final answer with no working typically caps you around level 3-4, not 7-8.

Generally no — unlike the DP Physics data booklet, most MYP schools expect Year 4-5 students to recall core equations from memory in unit tests, though some schools provide a school-specific reference sheet for eAssessment-style summative tasks. Check with your teacher, since this varies by school rather than being set centrally by the IB.

Yes — the on-screen MYP eAssessment for Sciences includes calculation-based questions requiring correct formula selection, rearrangement and substitution, typically marked against the same Criterion C descriptors used in classroom assessment. Practising under timed conditions matters because the on-screen calculator and answer boxes work differently to paper.

Watch for 'calculate', 'determine', 'deduce' and 'show that' — each expects a full working method including rearrangement, not just a stated answer. 'Show that' questions are especially strict: you're given the answer, so examiners check every algebra step to confirm you actually derived it correctly.

MYP builds the algebraic habits DP Physics later demands at speed — DP gives you a data booklet with equations, but you're expected to rearrange them instantly under exam pressure across two- and three-mark questions. Students who master rearranging properly in Year 4-5 have a real head start when DP Physics SL/HL begins.

It can be, since MYP Physics leans on algebra more than many parents expect — density, motion and electricity units all require confident equation manipulation. The good news is this is a learnable skill, not innate talent; consistent practice with worked examples closes the gap within a term in most cases I've seen.

The most useful thing you can do is ask your child to explain their rearrangement step aloud before they touch a calculator — verbalising the algebra catches errors early. Beyond that, past unit tests and topic-specific worksheets with worked solutions give far more useful practice than generic revision guides.