IB MYP Sciences Revision: Physics, Chemistry & Biology

March 2026 - 12 min read

The IB MYP sciences curriculum covers three disciplines - Physics, Chemistry, and Biology - each assessed through four criteria: Knowing and Understanding (A), Inquiring and Designing (B), Processing and Evaluating (C), and Reflecting on the Impacts of Science (D). This guide provides subject-specific revision strategies and advice for tackling each type of assessment question.

General Science Revision Principles

Before diving into subject-specific advice, here are principles that apply across all three sciences:

• Understand, do not memorise. Science questions rarely ask you to recite a definition word-for-word. They test whether you understand the concept well enough to apply it in unfamiliar contexts. Focus on understanding why things happen, not just what happens.
• Learn the language. Each science has precise terminology. Using the correct scientific vocabulary in your answers shows the examiner that you understand the concepts. "The particles move faster" is weaker than "the kinetic energy of the particles increases."
• Practise calculations. Science calculations follow patterns. Once you recognise the pattern (identify the formula, substitute values, solve), they become straightforward. The most common error is not converting units before substituting.
• Draw diagrams. A well-labelled diagram can communicate understanding more effectively than a paragraph of text. Practise drawing key diagrams until you can reproduce them quickly and accurately.

Physics Revision

Physics is the most mathematical of the three sciences. Success depends on being comfortable with equations and their rearrangements, interpreting graphs, and applying concepts to real-world situations.

High-Priority Topics

• Mechanics - This is the largest topic and appears in nearly every assessment. Focus on Newton's three laws, free-body diagrams, SUVAT equations for motion, and energy transfers. Practise drawing and interpreting distance-time and velocity-time graphs.
• Electricity - Understand Ohm's law (V = IR) and how to calculate power (P = IV) and energy (E = Pt). Be able to analyse series and parallel circuits, including calculating total resistance and current distribution.
• Waves - Know the wave equation (v = f x wavelength) and the difference between transverse and longitudinal waves. Be able to describe reflection, refraction, and diffraction with diagrams.

Common Mistakes in Physics

• Forgetting to convert units (e.g., km/h to m/s, minutes to seconds, cm to m)
• Confusing mass and weight (mass is in kg, weight is a force in N)
• Not including direction for vector quantities (velocity, force, acceleration)
• Reading graph axes incorrectly - always check what the axes represent and their units

Chemistry Revision

Chemistry bridges the mathematical (stoichiometry, energetics) and the descriptive (bonding, organic chemistry). A strong foundation in atomic structure makes everything else easier to understand.

High-Priority Topics

• Atomic Structure & Bonding - Everything in chemistry builds on this. Understand electron configuration, how it determines bonding behaviour, and the three types of bonding (ionic, covalent, metallic). Be able to draw dot-and-cross diagrams and explain properties of substances based on their bonding.
• Stoichiometry - Mole calculations are tested in almost every assessment. Practise converting between mass, moles, and number of particles. Know how to balance equations, identify limiting reagents, and calculate percentage yield.
• Acids & Bases - Understand the pH scale, neutralisation reactions, and the difference between strong and weak acids. Be able to write balanced equations for acid-base reactions and describe titration procedures.

Common Mistakes in Chemistry

• Confusing atoms and molecules, elements and compounds
• Unbalanced equations - always check that atom counts match on both sides
• Mixing up endothermic and exothermic - remember: exothermic releases heat (temperature rises), endothermic absorbs heat (temperature falls)
• Forgetting state symbols in equations (s, l, g, aq)

Biology Revision

Biology has more content to learn than physics or chemistry, but the concepts are generally more intuitive because they relate to living things you can observe. The challenge is the volume of terminology and the need to explain processes in detail.

High-Priority Topics

• Cells - Know the structure and function of every organelle in plant and animal cells. Be able to compare prokaryotic and eukaryotic cells. Understand mitosis and meiosis, including why each type of cell division is needed.
• Ecology - Understand food webs, energy transfer between trophic levels (and why only ~10% transfers), nutrient cycles (carbon and nitrogen), and biodiversity. Be able to interpret population data and discuss human impacts on ecosystems.
• Photosynthesis & Respiration - These are the two most important biological processes. Know the word equations and balanced chemical equations for both, the conditions needed, and where each occurs in the cell. Understand limiting factors for photosynthesis.

Common Mistakes in Biology

• Saying plants "breathe in CO2" - plants absorb CO2 for photosynthesis, but they also respire using oxygen
• Confusing mitosis and meiosis - mitosis produces identical cells (growth/repair), meiosis produces gametes (sex cells) with half the chromosomes
• Vague answers - "the enzyme breaks down" is too imprecise. Say "the enzyme denatures because the active site changes shape and the substrate can no longer bind"
• Forgetting that correlation does not equal causation when discussing experimental results

Tackling Different Question Types

Criterion A: Knowing and Understanding

These test factual knowledge and comprehension. Be precise with terminology, show all working for calculations, and answer exactly what is asked. If the question says "state," give a brief answer. If it says "explain," provide a reason.

Criterion B: Inquiring and Designing

These ask you to design experiments or identify variables. Always identify the independent variable (what you change), dependent variable (what you measure), and controlled variables (what you keep the same). Describe your method step-by-step, including equipment, sample sizes, and how you will ensure reliability (repeats).

Criterion C: Processing and Evaluating

These involve analysing data, drawing graphs, and evaluating results. Choose the correct graph type (bar chart for categories, line graph for continuous data, scatter graph for correlation). Include titles, labelled axes with units, and appropriate scales. When evaluating, discuss reliability, validity, and sources of error.

Criterion D: Reflecting on Impacts

These require you to discuss the social, ethical, economic, or environmental implications of science. Structure your answer with clear points for and against, supported by specific examples. Consider multiple perspectives - what might a scientist, an environmentalist, and a business owner each think?

Related Guides

• Understanding IB MYP Assessment Criteria
• How Spaced Repetition Helps You Remember Everything
• 5 Active Recall Techniques That Actually Work