Speed
v = speed (m/s), s = distance (m), t = time (s)
v = s / t Cambridge O Level 5129
🔬 O Level Combined Science Formula Sheet 2026
Key equations and relationships for Cambridge O Level Combined Science (5129) — Physics, Chemistry and Biology in one reference sheet.
Physics Chemistry Biology Exam Ready
Our formula sheets are free to download — save this one as PDF for offline revision.
Aligned with the latest 2026 syllabus and board specifications. This sheet is prepared to match your exam board’s official specifications for the 2026 exam series.
Physics, Chemistry and Biology Formulas in One Place
Cambridge O Level Combined Science (5129) covers selected topics from Physics, Chemistry and Biology. This sheet brings together all the key formulas and relationships you need across all three science disciplines.
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Physics: mechanics, electricity, waves
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Chemistry: moles, rates, equations
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Biology: cells, respiration, genetics
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Practical skills and data analysis
Physics Formulas
Always include units. Show substitution before calculating.
Acceleration
a = acceleration (m/s²)
a = (v − u) / t Force
F = force (N), m = mass (kg), a = acceleration (m/s²)
F = ma Weight
g ≈ 10 N/kg on Earth
W = mg Work Done
W = work (J), F = force (N), d = distance (m)
W = Fd Power
P = power (W), W = work (J), t = time (s)
P = W / t Pressure
P = pressure (Pa), F = force (N), A = area (m²)
P = F / A Ohm's Law
V = voltage (V), I = current (A), R = resistance (Ω)
V = IR Electrical Power
P = power (W)
P = IV Wave Speed
v = speed (m/s), f = frequency (Hz), λ = wavelength (m)
v = fλ Specific Heat Capacity
Q = heat energy (J), c = specific heat capacity (J/kg°C)
Q = mcΔT Chemistry Formulas
Moles
n = moles, m = mass (g), Mr = molar mass (g/mol)
n = m / Mr Concentration
c = concentration (mol/dm³), V = volume (dm³)
c = n / V Moles from Gas Volume (RTP)
V = volume (dm³). At room temperature and pressure.
n = V / 24 Percentage Yield
% yield = (actual / theoretical) × 100% Photosynthesis
Light energy required, chlorophyll as pigment.
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ Aerobic Respiration
Energy released as ATP.
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O Neutralisation
Acid + Base → Salt + Water Electrolysis — Charge
Q = charge (C), I = current (A), t = time (s)
Q = It Biology Formulas and Key Relationships
Magnification
Convert to same units first.
Magnification = image size / actual size Osmosis
Water moves from higher water potential to lower water potential across a partially permeable membrane.
Photosynthesis Word Equation
Carbon dioxide + Water → Glucose + Oxygen Aerobic Respiration Word Equation
Glucose + Oxygen → Carbon dioxide + Water (+ energy) Anaerobic Respiration (muscle)
Glucose → Lactic acid (+ energy) Population Estimate
Mark-release-recapture method.
N = (n₁ × n₂) / m Energy Transfer Efficiency
Efficiency (%) = (energy transferred to next level / energy at current level) × 100% Scientific Investigation Skills
Variables
Independent variable: what you change
Dependent variable: what you measure
Control variables: what you keep the same
Mean
Mean = sum of values / number of values Percentage Change
% change = (change / original) × 100% Gradient of a Graph
Use two points far apart on the line of best fit.
Gradient = rise / run = Δy / Δx How to Use This Formula Sheet
Boost your Cambridge exam confidence with these proven study strategies from our tutoring experts.
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Three subjects — prioritise your weak area
Use the O Level Combined Science paper breakdown to identify which section (P/C/B) has the most marks and where your gaps are.
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Practical questions
The exam includes data analysis and experimental design questions. Always identify independent, dependent and control variables.
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Chemistry: mole calculations
Write formula → substitute → include units. Moles questions often carry 2-3 marks — show every step.
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Biology: magnification
Always check you're in the same units before dividing. Convert mm to μm if needed (× 1000).
Formula Sheet FAQ
Quick answers about this free PDF and how to use it for exam revision and active recall.
Is the Cambridge O Level Combined Science Formula Sheet 2026 free to download as a PDF?
Yes. This Tutopiya formula sheet is free to use and you can download it as a PDF from this page for offline revision. There is no payment or account required for the PDF download.
What Combined Science topics and equations does this formula sheet cover?
This page groups key Combined Science formulas in one place for revision. Complete formula reference for Cambridge O Level Combined Science (5129). Key equations and relationships for Physics, Chemistry and Biology topics in the combined science syllabus. Always cross-check with your official syllabus and past papers for your exam session.
Can I use this instead of the official exam formula booklet in the exam?
No. In the exam you must follow only what your exam board allows in the hall—usually the official formula booklet or data sheet where provided. This page is a revision and teaching aid, not a replacement for board-issued materials.
Who is this formula sheet for (Secondary)?
It is written for students preparing for assessments at Secondary in Combined Science, including classroom revision, homework support, and independent study. Teachers and tutors can also share it as a quick reference.
How should I revise with this formula sheet?
Work through past paper questions, quote the correct formula before substituting values, and check units and notation every time. Pair this sheet with timed practice and mark schemes so you see how examiners expect working to be set out.
Where can I get more help with Combined Science revision?
Explore Tutopiya’s study tools, past paper finder, and revision checklists linked from our tools hub, or book a trial lesson with a subject specialist for personalised support alongside this formula reference.
Need Help with O Level Combined Science?
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This formula sheet aligns with Cambridge O Level Combined Science (5129) syllabus content.
Always check the specific 5129 syllabus for topic coverage — not all Physics, Chemistry and Biology topics from the separate sciences are included.