IGCSE Coordinated Science (0654) 2026 Study Guide

This guide maps key topics to the Cambridge IGCSE Co‑ordinated Sciences (Double Award) 0654 syllabus for 2026–2027. Use the links and summaries below to focus your revision. The course covers Biology (B1–B19), Chemistry (C1–C12), and Physics (P1–P6). The 2025–2027 syllabus introduced Space Physics as a new topic.

⚛️ Physics Topics

🔌 Electricity – Circuits & Ohm’s Law

P4 Electricity and magnetism

Learning objectives

Draw and interpret circuit diagrams with cells, batteries, switches, resistors (fixed and variable), ammeters, voltmeters, lamps, diodes, LEDs, thermistors and LDRs.
Understand that current is the same in a series circuit; voltage is shared.
State and use Ohm’s Law: V = IR.
Investigate how the resistance of a wire varies with length and temperature.

📌 Key points:

Ammeter (series) – symbol Ⓐ. Voltmeter (parallel) – symbol Ⓥ.
Variable resistor symbol: resistor with an arrow or movable contact.
Resistance R = V / I. For a metal wire at constant temperature, resistance ∝ length.

🧪 Common practical: Investigating resistance of a wire – measure current and voltage at different lengths. Plot resistance vs. length; gradient gives resistance per unit length.

📖 Open revision: investigating resistance

Set up a circuit with a power supply, switch, ammeter in series, test wire, and voltmeter across the wire.
Measure the length of wire using a ruler and keep the current low to reduce heating.
Record current and voltage, then calculate resistance using R = V ÷ I.
Repeat for different lengths and plot resistance against length.

Exam focus: Resistance should increase as wire length increases because electrons collide with more metal ions.

Ohm’s law: V = I × R | R = V / I

🔗 Open revision: circuit diagrams and resistance

Series circuits: current is the same everywhere; voltage is shared across components.
Parallel circuits: voltage is the same across each branch; current splits between branches.
Ammeter: connected in series. Voltmeter: connected in parallel.
Ohmic conductor: current is directly proportional to voltage when temperature stays constant.

Check yourself: Explain why a voltmeter must be placed across a component, not in series with it.

🌊 Waves – Light & Sound

P3 Waves

Learning objectives

Distinguish transverse (light) from longitudinal (sound) waves.
Describe reflection, refraction and total internal reflection (optical fibres).
Sound requires a medium; cannot travel in a vacuum.
Recall speed of light (3.0 × 10⁸ m/s) and speed of sound in air (~330 m/s).
Use wave equation: v = fλ.

📌 Comparison of light and sound waves:

Property	Light waves	Sound waves
Type of wave	Transverse	Longitudinal
Travel in a vacuum?	Yes	No
Speed in air	3.0 × 10⁸ m/s	~330 m/s (depends on temperature)

Wave speed: v = f × λ (m/s, Hz, m)

🧪 Sound speed calculation (echo method): v = (2 × distance) ÷ time. Example: cliff 170 m away, echo heard after 1.0 s → v = 340 m/s.

🔗 Open revision: general wave properties

Amplitude: maximum displacement from rest position.
Wavelength: distance from one point on a wave to the same point on the next wave.
Frequency: number of waves passing a point per second, measured in hertz.
Refraction: change in direction when a wave changes speed entering a new medium.

Check yourself: A sound wave travels 660 m in 2.0 s. Calculate its speed.

🔥 Thermal Physics – Energy & Latent Heat

P2 Thermal physics

Learning objectives

Define specific latent heat of fusion and vaporisation.
Interpret heating/cooling curves; understand why temperature remains constant during phase change.

📌 Definitions:

Specific latent heat of fusion (L_f) – energy to change 1 kg of solid → liquid at melting point, no temp change.
Specific latent heat of vaporisation (L_v) – energy to change 1 kg of liquid → gas at boiling point.

E = m × L (E in joules, m in kg, L in J/kg)

🔗 Open revision: specific latent heat

Latent heat is energy transferred during a change of state without a temperature change.
During melting or boiling, energy separates particles instead of increasing their kinetic energy.
Use E = mL, where E is energy, m is mass, and L is specific latent heat.

Check yourself: Explain why a heating curve has a flat section during melting.

🧪 Chemistry Topics

💧 Water of Crystallisation (Mole calculations)

C3 Stoichiometry

Key concept

Hydrated salts (e.g., Na₂CO₃·xH₂O) lose water on heating. Calculate x from mass loss.

📌 Method:

Mass of hydrated salt (before heating).
Mass of anhydrous salt (after heating to constant mass).
Mass of water lost = hydrated mass – anhydrous mass.
Moles of anhydrous salt = mass / M_r ; moles of water = mass of water / 18.0.
Ratio moles water : moles anhydrous salt → x.

Moles = mass ÷ molar mass | mass of H₂O lost = mass before − mass after

🧪 Equipment: Crucible, lid, pipe‑clay triangle, Bunsen burner, desiccator. Heat gently then strongly until constant mass.

🔗 Open revision: stoichiometry and water of crystallisation

Find the mass of water lost by subtracting the final mass from the initial mass.
Calculate moles of water using mass ÷ 18.
Calculate moles of anhydrous salt using mass ÷ formula mass.
Divide both mole values by the smaller value to find the simplest ratio.

Exam focus: Heating to constant mass proves that all water of crystallisation has been removed.

🔩 Rusting of Iron (Corrosion)

C10 Metals

Key facts

Rusting requires both oxygen and water. Rust is hydrated iron(III) oxide: Fe₂O₃·xH₂O.

📌 Prevention methods:

Barrier: painting, oiling, greasing, electroplating, plastic coating.
Sacrificial protection (e.g., zinc – galvanising).
Alloying: stainless steel (iron + chromium + nickel).

🧪 Classic experiment: Four nails: in air+water (rusts); in boiled water + oil (no rust); with calcium chloride (no rust); in salt water (faster rust).

🔗 Open revision: rusting and corrosion

Rusting needs both oxygen and water.
Salt water increases the rate of rusting because ions improve electrical conductivity.
Paint, grease, oil, plastic coating, and electroplating act as barriers.
Galvanising protects iron because zinc reacts more readily than iron.

Check yourself: Why does an iron nail not rust in boiled water covered with oil?

⚖️ Conservation of Mass – Magnesium oxide experiment

C3 Stoichiometry

Principle

Mass is conserved in a chemical reaction. When magnesium burns in air: 2Mg + O₂ → 2MgO. The increase in mass equals mass of oxygen combined.

Example: 5.0 g Mg → 8.3 g MgO ⇒ mass of oxygen = 3.3 g.

mass of oxygen = mass of oxide − mass of metal

🧪 Crucible method: Weigh crucible + lid + Mg, heat strongly, allow to cool, reweigh. Repeat to constant mass.

🧬 Biology Topics

🩸 Blood Components (Microscope identification)

B9 Transport in animals

Key points

Red blood cells: biconcave discs, no nucleus, contain haemoglobin – carry oxygen.
White blood cells: larger, have a nucleus; phagocytes and lymphocytes fight infection.
Platelets: small fragments, involved in clotting.
Plasma: liquid carrier for dissolved substances.

🔗 Open revision: components of blood

Red blood cells: carry oxygen using haemoglobin; no nucleus gives more space for haemoglobin.
White blood cells: defend the body using phagocytosis and antibody production.
Platelets: help blood clot at wounds.
Plasma: transports carbon dioxide, urea, hormones, glucose, amino acids and heat.

Exam focus: In microscope questions, look for cell size, shape, and whether a nucleus is visible.

🥔 Osmosis in Potato Cylinders

B3 Movement into & out of cells

Required practical

Investigate the effect of sucrose concentration on potato mass.

Water moves by osmosis from high water potential (dilute) to low water potential (concentrated) through a partially permeable membrane.
Isotonic point: no net movement – potato water potential equals external solution.
As sucrose concentration increases, potato loses mass (water leaves cells).

Percentage change in mass = ((final mass − initial mass) ÷ initial mass) × 100

🧪 Method: Use cork borer for equal cylinders; initial mass; place in sucrose solutions (0 M to 1.0 M); after 20 min, blot dry, reweigh; plot % change vs. concentration.

🔗 Open revision: osmosis experiments

Cut equal-sized potato cylinders using a cork borer.
Measure initial mass and place cylinders in different sucrose concentrations.
After a fixed time, blot dry and measure final mass.
Calculate percentage change in mass and plot against sucrose concentration.

Exam focus: The isotonic point is where percentage change in mass is zero.

🔬 Diffusion – Potassium manganate(VII) demonstration

B3 Movement into & out of cells

A crystal of potassium manganate(VII) in water produces a purple colour that spreads without stirring – this is diffusion (net movement from high to low concentration).

Factors affecting diffusion: temperature, concentration gradient, distance, particle size.

🧫 Practical Skills (Alternative to Practical)

📊 Graph plotting & analysis

Skills: drawing graphs, lines of best fit, gradient

Use pencil; independent variable on x‑axis, dependent on y‑axis; label axes with units.
Choose scales so data fills >50% of graph paper.
Draw a line of best fit (straight or curved, not dot‑to‑dot).
Calculate gradient = Δy ÷ Δx for straight lines.

🧪 Required practicals summary

Full list on Cambridge School Support Hub

Physics: I‑V characteristics, resistance of a wire, speed of sound (echo).
Chemistry: Water of crystallisation, rusting, preparing salts, titration (Extended).
Biology: Osmosis in potato, enzyme activity (amylase), food tests (Benedict’s, biuret, iodine, ethanol).

🔗 Open revision: practical skills checklist

Variables: identify independent, dependent, and controlled variables.
Reliability: repeat readings and calculate a mean.
Accuracy: use suitable apparatus and read scales at eye level.
Safety: identify hazards and give specific precautions.
Graphs: choose sensible scales, label axes with units, and draw a line of best fit.

Exam focus: When asked for an improvement, explain how it improves the quality of the results.

📐 Mathematical Requirements

Rearrange formulas: V = IR, E = mL, v = fλ, moles = mass/M_r.
Calculate averages, percentages, percentage changes, gradients.
Convert units: cm → m, g → kg, mm³ → cm³.
Plot and interpret graphs (scatter graphs with lines of best fit).

✅ Final revision checklist

☐ Know transverse vs. longitudinal waves (light vs. sound).
☐ Practice mole calculations (water of crystallisation, reacting masses).
☐ Draw circuit symbols (ammeter, voltmeter, variable resistor).
☐ Describe potato osmosis experiment and identify isotonic point.
☐ Conditions for rusting (oxygen + water) and three prevention methods.
☐ Explain latent heat – constant temperature during melting/boiling.
☐ Use wave equation v = fλ.
☐ Conservation of mass – magnesium oxide crucible experiment.
☐ Review practical past paper questions: variables and improvements.

Based on Cambridge IGCSE Co‑ordinated Sciences (Double Award) 0654 syllabus for 2025–2027. Always refer to the official syllabus document for detailed learning outcomes.