CBSE Class 10 Science. Physics. Chemistry. Biology. All three.
Science is three subjects in one paper — Physics numericals, Chemistry equations, Biology diagrams. Each requires a completely different approach. Here's the chapter priority and preparation method for all three, starting in August.
CBSE Class 10 Science — chapter priorities and preparation strategy for all three parts
Understanding how the Science paper is structured
CBSE Class 10 Science paper is 80 marks theory for 3 hours. Physics contributes approximately 25–27 marks (Electricity, Light, Magnetic Effects), Chemistry approximately 23–25 marks (Chemical Reactions, Acids/Bases/Salts, Metals, Carbon Compounds), and Biology approximately 28–30 marks (Life Processes, Control and Coordination, Reproduction, Heredity, Ecology).
Knowing this split helps you allocate preparation time. Biology carries the highest marks but rewards text-based recall. Physics and Chemistry require numerical practice and reaction writing — different skills that need separate practice time.
Physics — Electricity and Light are guaranteed marks
Electricity (Chapter 12) and Light — Reflection and Refraction (Chapter 10) together appear in every CBSE Class 10 Science paper without exception. Electricity numericals: Ohm's law, series and parallel resistance, power and energy calculations. These same question structures repeat — only the values change.
Light: mirror and lens formula numericals, ray diagrams, and power of a lens are perennial. Magnetic Effects of Current (Chapter 13) adds 5–7 marks. Build a formula sheet for Physics (Ohm's law, lens and mirror formulas, power equations) and practise numericals until the method is automatic.
Chemistry — reactions are the marks
Chemical Reactions and Equations (Chapter 1), Acids, Bases and Salts (Chapter 2), and Carbon and Its Compounds (Chapter 4) carry the most Chemistry marks consistently. Balancing equations: CBSE tests 2–3 balanced equation problems per paper — practise until balancing is fast and accurate.
For Carbon Compounds: know the functional groups, homologous series, and naming rules. Combustion, addition, and substitution reactions are the most tested. Acids/Bases: pH scale, indicators, and neutralisation reactions are predictable 2–3 mark questions. For Metals and Non-Metals: reactivity series and displacement reactions appear every year.
Biology — diagrams and process-based answers
Life Processes (Chapter 6), Reproduction (Chapter 8), and Heredity and Evolution (Chapter 9) are the highest-weight Biology chapters in Class 10 Science. Life Processes covers nutrition, respiration, transport, and excretion — all tested through labelled diagrams and process explanations.
Must-practise diagrams: human digestive system, human heart, nephron, flower cross-section, germination stages, and neuron structure. Each diagram carries 1–2 marks and requires specific labels. Practise drawing each 3 times with all required labels from memory.
Starting in August — the Science preparation timeline
August: Chemical Reactions and Acids/Bases (Chemistry foundation — early chapters that are exam-heavy). September: Life Processes and Carbon Compounds. October: Electricity and Light (Physics core — practise numericals daily). November: Reproduction, Heredity, Magnetic Effects, Metals. December: Ecology, remaining chapters, diagram revision.
From January: full Science paper practice once a week. Science improves fastest in the final 8 weeks for students who have the chapters covered — the combination of familiarity and practice converts into marks quickly.
Ready to get started? Try ClearSteps free for 14 days.
Start my 14-day free trialThree tools used every day till the boards
Drills the chapters that matter
Questions weighted to the real CBSE exam pattern — not last year's book. Practise what actually shows up in the paper.
Build a fresh test in 30 seconds
Pick subject, chapters, marks, difficulty. An exam-style timed paper ready to go. Unlimited.
Every PYQ, decoded
Previous year papers 2015–2025, all subjects, with official marking schemes and an AI pattern read.
Frequently asked questions
Which chapters are most important for CBSE Class 10 Science?
Physics: Electricity and Light — Reflection and Refraction. Chemistry: Chemical Reactions and Equations, Acids Bases and Salts, Carbon and Its Compounds. Biology: Life Processes, Reproduction, Heredity and Evolution. These chapters appear in every paper and together account for 55–60 marks out of 80.
How to score 90+ in CBSE Class 10 Science?
Master the six high-frequency chapters. Practise Physics numericals with complete step-wise working. Know all required Biology diagrams with correct labels. Write balanced chemical equations accurately. Solve 5 full previous year Science papers under 3-hour conditions and check each answer against the official CBSE marking scheme.
Is CBSE Class 10 Science hard?
Science is challenging because it is three subjects in one. The content from Physics, Chemistry, and Biology must all be prepared separately with different methods. But the CBSE paper is NCERT-based, and the question types repeat consistently across years. Students who prepare all three parts systematically find the paper very manageable.
How to prepare for Class 10 Science in 6 months?
Month 1 (August): Chemical reactions, Acids/Bases, Life Processes. Month 2 (September): Carbon compounds, Electricity. Month 3 (October): Light, Reproduction, Heredity. Month 4 (November): Metals, Magnetic effects, Control and coordination. Month 5 (December): Ecology, Sources of energy, revision. Month 6 (January): Full paper practice only.
How are numericals marked in Class 10 Science?
CBSE awards step marks for Science numericals exactly as in Maths. Write the formula first, then substitute values with units, then solve step-by-step, then write the final answer with units. A correct method with a calculation error earns most of the marks. A correct answer with no shown steps may earn zero for the working marks.
Related guides
Class 10 Science — Physics, Chemistry, Biology in one plan.
Chapter weights, diagram guide, PYQ analysis, AI question bank. 14 days free, no card needed.
No card needed · Activate on WhatsApp in 30 seconds