Combined Science GCSE Subject Content Notes (2015)

Working scientifically

  • This GCSE Combined Science content is built around two main dimensions:

    • Working scientifically: development and assessment of scientific thinking, experimental skills, data analysis and evaluation, scientific vocabulary, quantities, units, symbols and nomenclature. Includes ethical, social and environmental considerations, risk assessment, peer review, and communication of results.

    • Subject content in Biology, Chemistry and Physics with a minimum of 30% for each of the three disciplines in a combined science specification.

  • Four general areas for developing working scientifically: 1) Development of scientific thinking

    • How scientific methods and theories develop over time

    • Use of various models (representational, spatial, descriptive, computational, mathematical) to solve problems and predict phenomena

    • Recognising the power and limitations of science and considering ethical issues

    • Explaining everyday and technological applications of science and evaluating implications

    • Risk assessment in practical science and societal context; data interpretation and consequences

    • Peer review and communicating results to diverse audiences
      2) Experimental skills and strategies

    • Formulating hypotheses using scientific theories and explanations

    • Planning experiments and procedures to observe, test hypotheses, or characterise substances

    • Selecting appropriate techniques, instruments, materials; health and safety considerations

    • Sampling techniques to ensure representativeness; accurate observations and measurements

    • Evaluating and suggesting improvements and further investigations
      3) Analysis and evaluation

    • Collecting, presenting and analysing data; translating data forms

    • Mathematical and statistical analysis; recognizing patterns and trends

    • Drawing conclusions and relating data to hypotheses

    • Evaluating data for accuracy, precision, repeatability and sources of error

    • Communicating rationale, findings and conclusions in written and electronic formats
      4) Scientific vocabulary, quantities, units, symbols and nomenclature

    • Use of SI units, IUPAC nomenclature where appropriate, and conversion between units

    • Knowledge of prefixes (e.g., kilo-, centi-, milli-) and orders of magnitude

  • Mathematics in science: integration of math skills with science content (see Appendix 3 for details). Students should be able to apply mathematics to interpret data, calculate rates, proportion, and handle graphs, units, and equations.

  • Appendices provide essential formulae, units and mathematical skills (see Appendices 1–4).

Biology

  • Biology is the science of living organisms and their interactions; content focuses on key ideas applicable across topics:

    • Life processes depend on molecules whose structure relates to function

    • Cells are the fundamental units; tissues, organs and organ systems enable life processes

    • Populations, communities and ecosystems with interdependencies including humans

    • Organisms adapt to their environment; evolution and natural selection explain biodiversity and relatedness

    • Photosynthesis links plants as primary producers producing biomass

    • Organic compounds are used in cellular respiration to drive other reactions

    • Material cycling connects biotic and abiotic components

    • Genome influences organism traits; environment interaction affects phenotype

    • Evolution through natural selection explains adaptation and speciation

  • Biology content covers: cell biology; growth and development of cells; cell metabolism; transport systems; health, disease and medicines; coordination and control; photosynthesis; ecosystems; inheritance, variation and evolution.

  • Higher and foundation tier expectations apply; depth and breadth may vary, but all listed content should be assessed.

Cell biology

  • Prokaryotic and eukaryotic cells; sub-cellular structures and their functions

    • Nucleus/genetic material, plasmids, mitochondria, chloroplasts and cell membranes

    • Electron microscopy increases understanding of sub-cellular structures

  • Growth and development of cells

    • Mitosis and the cell cycle; differentiation; cancer as uncontrolled growth

    • Role of stem cells in embryonic/adult animals and meristems in plants; benefits/risks of stem cells in medicine

    • Meiosis in forming gametes (halving chromosome number)

  • Cell metabolism

    • Enzyme action: active site, specificity, factors affecting rate of reaction

    • Cellular respiration: aerobic vs anaerobic; exothermic process; importance of sugars, amino acids, fatty acids, glycerol in synthesis and breakdown of carbohydrates, lipids and proteins

  • Use of mathematics (in biology)

    • Understand number, size and scale; rate calculations; estimation; plotting and interpreting graphs

    • Connections to experimental data and biological rate processes

  • Transport systems

    • Transport into/out of cells via diffusion, osmosis and active transport

    • Exchange surfaces and SA:V ratio for multicellular organisms; transport needs (O2, CO2, water, nutrients, minerals, urea)

    • Human circulatory system: heart and vessels adaptations; blood components (RBCs, WBCs, platelets, plasma)

    • Plant transport: xylem and phloem structure; root hair cells; transpiration and translocation; stomata structure/function

  • Use of mathematics (transport)

    • SA:V ratios; rate calculations; plotting and interpreting graphs; percentage mass changes

  • Health, disease and medicines

    • Health vs disease; communicable and non-communicable diseases; spread of communicable diseases in animals/plants; examples including HIV/AIDS; non-specific immune defence; role of immune system

    • Vaccines and medicines; discovery and development of new medicines including preclinical and clinical testing

    • Reducing spread of communicable diseases; the impact of infections and disease control strategies

  • Coordination and control

    • Nervous coordination: structure and adaptation of CNS, neurons, receptors; reflex arcs

    • Hormonal coordination: endocrine system; roles of thyroxine and adrenaline (negative feedback example)

  • Homeostasis and hormones

    • Internal environment regulation; insulin and glucagon control of blood sugar; type 1 vs type 2 diabetes and treatments

  • Photosynthesis

    • Process and endothermic nature; producers of biomass; effect of temperature, light intensity, CO2 on rate; limiting factors and their interaction

  • Ecosystems

    • Levels of organisation; abiotic/biotic factors; interdependence and competition; material cycling (carbon and water cycles); role of microorganisms in cycling

    • Biodiversity: field investigations; human impacts; benefits and challenges of maintaining biodiversity

  • Inheritance, variation and evolution

    • Genome and gene expression; DNA as a polymer; genes, alleles, genotype/phenotype; influence of environment on phenotype; medical relevance of genomes

    • Single gene inheritance; genetic crosses; polygenic traits; sex determination in humans

    • Variation and evolution: genetic variation, mutations, natural selection, speciation; evidence (fossils, antibiotic resistance); classification changes; selective breeding and genetic engineering; benefits/risks and ethics

  • Use of mathematics (inheritance and evolution)

    • Genotype/phenotype probabilities; direct proportions in crosses; interpreting charts/graphs

    • Probability in predicting genetic outcomes; charts and tables interpretation

Chemistry

  • Chemistry is the science of matter, its composition, structure, properties and reactions, on atomic and molecular levels; aims to show how complex phenomena can be explained with few universal ideas.

  • Core ideas common to chemistry across biology and physics include:

    • Matter is composed of atoms; about 100 naturally occurring elements

    • Elements show periodic relationships; periodic table trends linked to electron arrangements

    • Atoms bond by transferring or sharing electrons; molecular shapes and giant structures influence properties

    • Reaction rates are influenced by barriers and conditions; energy is conserved in reactions

    • Reactions occur by proton transfer, electron transfer, or electron sharing; energy is conserved

  • Chemistry content covers: Atomic structure and the Periodic Table; Structure, bonding and the properties of matter; Chemical changes; Energy changes in chemistry; The rate and extent of chemical change; Chemical analysis; Chemical and allied industries; Earth and atmospheric science; Energy uses of mathematics; and connections to SI units and mathematical skills (Appendices).

Atomic structure and the Periodic Table

  • Simple atomic model: nucleus with protons and neutrons; electrons in orbit; nucleus much smaller than atom; most mass in nucleus

  • Atomic number Z and mass number A; isotopes differ in neutron number; Charge balance

  • Modern periodic table: element position related to electron arrangement; isotopes and altered row placement (Mendeleev’s model context)

  • Properties of Groups 1, 7 and 0 explained by outer electron configuration; trends down groups; reactivity predictions from position

  • Metals vs non-metals; periodic table position related to properties

  • Basic calculations: number of protons, neutrons, electrons in atoms and ions from Z and A; simple formulae and balanced equations for reactions

  • Chemical symbols, formulae and equations; empirical formula from atom counts or models; conservation of mass in reactions; formulae to ionic equations

Structure, bonding and the properties of matter

  • States of matter, particle model and energy transfer in changes of state; limitations of the particle model

  • Bond types: ionic, covalent, metallic; electron transfer or sharing; dot-and-cross diagrams; limitations of diagrams and 3D representations

  • How bulk properties relate to bonds and structure; bond strengths and intermolecular forces; influence on melting/boiling points and material properties

  • Structure and bonding of carbon: carbon can form four covalent bonds; carbon compounds form families (chains, rings); properties of diamond, graphite, fullerenes and graphene

Chemical changes

  • Chemical symbols, formulae and equations; empirical and molecular formula calculation; mass conservation; balancing equations; half-equations and ions

  • Identification of common gases and gas tests (O2, H2, CO2, Cl2)

  • Acids and bases: pH concepts; neutralisation and salts; dilute/strong/weak acids, H+ concentration and pH scale

  • Redox and electrochemistry: reduction/oxidation in terms of electron transfer; alkalis and hydroxide; strong vs weak acids; pH changes; reactivity series and metal extraction; electrolysis in molten and aqueous ionic compounds; electrode products

Energy changes in chemistry

  • Exothermic and endothermic reactions; reaction profiles and activation energy; interpreting energy diagrams

  • Bond breaking and making energies; calculating overall energy changes via bond energies

  • Carbon compounds as fuels and feedstock; crude oil as a main hydrocarbon source; finite resource consideration

  • Basic quantitative handling of energy changes (arithmetic) and graph interpretation of reaction profiles

The rate and extent of chemical change

  • Rates of reaction influenced by temperature, concentration, pressure and surface area; catalysts and their role in increasing rate; activation energy concept

  • Practical methods to determine rate; interpreting rate graphs; relation to particle collision frequency and energy

  • Reversible reactions and dynamic equilibrium; effect of changing conditions on equilibrium position; Predicting conditions to favour a product

  • Mathematical handling: rate calculations, graph interpretation, proportionality in rate factors

Chemical analysis

  • Purity and formulations; separation techniques (filtration, crystallisation, simple/distillation, fractional distillation); chromatography basics and interpretation of chromatograms (Rf values)

  • Melting point to assess purity; impurity effects on melting point

  • Purity, formulations and material separation concepts

  • Conservation of mass in reaction contexts and mass changes in non-closed systems

Chemical and allied industries

  • Life-cycle assessment concepts; recycling and material sustainability; industrial processes for refining and converting hydrocarbons; fractional distillation and cracking; gasoil/fraction specifications

  • Metal extraction: reactivity series; extraction methods from ores; electrolysis for some metals; alternative biological extraction methods (bacterial and phytoextraction); environmental and ethical considerations

  • Energy and resource use across industries; impact assessment and socio-economic factors

Earth and atmospheric science

  • Earth’s atmosphere composition and evolution; formation and changes over time; greenhouse gases (CO2 and CH4) and the greenhouse effect; anthropogenic contributions and climate change evidence and uncertainties; scale and environmental implications

  • Common atmospheric pollutants and sources (CO, SO2, NOx, particulates) and their effects

  • Water resources and potable water production; methods to increase water availability; treatment and purification techniques

  • Energy context: drivers and implications of energy resource use; environmental, social and economic dimensions

Use of mathematics (chemistry integration)

  • Translating information between graphical and numerical forms; using charts and tables; sampling principles; correlation via scatter diagrams; cross-sectional areas and geometric calculations (e.g., πr^2)

  • Concentration, rates, energy calculations, and stoichiometry; empirical formula calculations and molar relationships

Earth science and climate context

  • Interpretation of data related to climate drivers and greenhouse gas effects; scale of effects and uncertainties in evidence

Physics

  • Physics provides a set of universal ideas: models, cause and effect, action at a distance, energy transfer, proportionality, and mathematical expression of laws

  • Topics include energy, forces, waves, electricity, magnetism and electromagnetism, particle theory of matter, and atomic structure; these topics interlink to describe natural phenomena and technology

  • Higher-tier content must cover all listed content; foundation-tier must assess non-underlined material; both tiers require mathematical skills and practical competencies

Energy

  • Energy changes in systems; energy stored in different forms; calculating energy for moving objects, stretched springs, raised objects

  • Power and energy transfer: power as rate of energy transfer; energy changes due to heating, work, and electrical work; power relations with voltage, current and resistance

  • Quantities and units: energy, work, power, specific heat capacity, and specific latent heat; relationships like

    • change in thermal energy: \Delta Q = m c \Delta T

    • energy in stretching a spring: \Delta E = \tfrac{1}{2} k x^2

  • Energy efficiency and dissipation; energy transfers in domestic appliances; energy resources and sustainability; renewable vs non-renewable sources

  • Domestic energy and the national grid; energy transfer efficiency; qualitative description of energy flows

  • Mathematical use: express energy changes using appropriate equations and interpret energy graphs

Forces

  • Forces and interactions: gravity, electrostatic, magnetism, contact forces; vector representation; weight and gravitational field strength

  • Free-body diagrams for multiple forces; resultant forces and equilibrium; elastic vs inelastic deformation; spring constant and Hooke’s law

  • Work done by forces, energy transfer via forces and distance; relationship: W = F d

  • Vector resolution and equilibrium using vector diagrams

  • Energy and force relationships in springs and other systems; linear vs non-linear behavior

Forces and motion

  • Speed, velocity, acceleration; distance-time and velocity-time graphs; vector-scalar distinction (displacement vs distance, velocity vs speed)

  • Typical speeds and accelerations; circular motion concept (constant speed, changing velocity)

  • Newton’s laws: First Law (equilibrium with constant velocity), Second Law (F = ma) and Third Law (action-reaction)

  • Inertial mass as measure of resistance to acceleration; momentum concepts in collisions

  • Safety and reaction time in public transport contexts; factors affecting stopping distance; safety implications

  • Mathematics in motion: unit conversion, rate calculations, distance-time and velocity-time graph interpretation; area under velocity-time graphs corresponds to distance travelled

Waves in matter

  • Wave motion concepts: amplitude, wavelength, frequency and period; wave velocity relation v = f \lambda

  • Transverse vs longitudinal waves; water surface ripples vs sound waves; measurement approaches

  • Light and electromagnetic waves; spectrum grouping (radio to gamma); velocity in vacuum; energy transfer by EM waves; hazard awareness with UV, X-ray, gamma

  • Mathematical use: relation between velocity, frequency and wavelength; energy and frequency relationships for EM waves

Light and electromagnetic waves (spectrum and interaction)

  • EM waves are transverse; travel through space at the same speed; energy transfer from source to absorber

  • Interaction with matter: absorption, transmission, refraction, reflection; wavelength-dependent effects

  • Practical uses across regions: radio, microwave, infrared, visible, ultraviolet, X-ray, gamma

  • UV, X-ray, gamma hazards to biological tissue

Electricity

  • Current as rate of flow of charge; relationship with time and charge; I = Q / t

  • Resistance and potential difference; V = I R; circuit behaviour and characteristics of resistors

  • Series vs parallel circuits; total resistance changes in series vs parallel

  • DC circuit calculations: currents, voltages and resistances; circuit conventions (positive/negative terminals); circuit elements (diodes, LDRs, thermistors)

  • Domestic electricity: UK mains supply (AC, ~230 V, 50 Hz); live/neutral/earth wires; dangers of live conducting even when switch is open

  • Energy transfer in circuits: power, energy, and time; energy transferred by devices; high-voltage transmission efficiency

  • Use of mathematics to solve circuit problems; linear vs non-linear elements; graph interpretation of circuits

Magnetism and electromagnetism

  • Permanent and induced magnetism; magnetic fields; attraction/repulsion of poles; Earth’s magnetic core evidence via compass

  • Electromagnetic effects: currents produce magnetic fields; strength depends on current and distance; solenoids enhance magnetic effects

  • Motors: force on a current-carrying conductor in a magnetic field; Fleming’s left-hand rule; calculation of magnetic force: F = B I L

  • Applications in motors and generators; electromagnetic induction principles

Particle model of matter

  • Density and states of matter; changes of state conserve mass but properties may change chemically; particle-level interpretation

  • Internal energy and particle motion; heating changes energy stored; specific heat capacity and latent heat; gas particle motion and PV relationships (qualitative description)

  • Density, mass and volume relationships; energy change equations for heating and phase changes

Atomic structure

  • Nuclear atom and isotopes: nucleus with protons and neutrons; electrons in shells; nucleus mass dominates; isotopes differ by neutron number; nuclear radius is small

  • Absorption and emission of radiation; ionisation and electron arrangements; radioactive decay and half-life; alpha, beta and gamma radiation; hazard distinctions between contamination and irradiation

  • Use of nuclear equations to balance decays; half-life concept and randomness of decay

Appendix 1: Equations in physics (high tier emphasis)

  • Principal relationships to recall/apply with standard SI units:

    • Force: F = m a

    • Kinetic energy: K = \tfrac{1}{2} m v^2

    • Momentum: p = m v

    • Work done: W = F d

    • Power: P = \dfrac{W}{t}

    • Efficiency: \eta = \dfrac{\text{output energy transfer}}{\text{input energy transfer}}

    • Gravity force: F_g = m g

    • Potential energy: U = m g h

    • Spring force: F = k x

    • Distance: s = v t

    • Acceleration: a = \dfrac{\Delta v}{t}

    • Wave speed: v = f \lambda

    • Charge flow: Q = I t

    • Potential difference: V = I R

    • Power in circuits: P = V I = I^2 R

    • Energy transferred: E = P t = Q V

    • Density: \rho = \dfrac{m}{V}

  • Additional relationships:

    • (final velocity)^2 − (initial velocity)^2 = 2 a s

    • Change in thermal energy = \Delta Q = m c \Delta T

    • Thermal energy for a change of state = Q = m L

    • Energy in stretching = \Delta E = \tfrac{1}{2} k x^2

    • Transformer relation: Vp Ip = Vs Is

    • Magnetic force on a conductor: F = B I L

Appendix 2: SI units

  • Base units: metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), mole (mol)

  • Derived units with special names: frequency (Hz), force (N), energy (J), power (W), pressure (Pa), electric charge (C), electric potential difference (V), electric resistance (Ω), magnetic flux density (T)

Appendix 3: Mathematical skills required (biology, chemistry, physics, and combined science)

  • Arithmetic and numerical computation: decimal form, standard form, ratios, fractions, percentages; estimation; operations with significant figures

  • Handling data: significant figures, arithmetic means, frequency tables and diagrams (bar charts, histograms); sampling principles; probability; mean, mode, median

  • Algebra: symbols, solving equations, changing subject, substituting values with units, simple algebraic equations

  • Graphs: translating data to/from graphs; linear relations (y = mx + c); plotting two variables; slope/intercept; rate of change; area under curves

  • Geometry and trigonometry: angular measures; 2D/3D representations; areas and volumes; trigonometric concepts where applicable

  • These skills are used to enhance analysis and interpretation across all science topics

Appendix 4: List of apparatus and techniques

  • Biology: measurement, microscopy, data recording; observation and measurement of biological changes; safe and ethical use of living organisms

  • Chemistry: observing chemical reactions; pH measurement; purification and separation techniques; chromatography; distillation; observation of chemical changes

  • Physics: measuring motion (speed, rate of change); energy changes and transfers; measuring currents, voltages, resistances; circuit construction and testing

  • Emphasises safety and appropriate use of apparatus, recording of measurements, and analysis of results in a range of contexts

Earth and atmospheric science (within Chemistry section)

  • Atmosphere composition and evolution; greenhouse gases and climate change evidence, uncertainties and potential mitigation strategies

  • Major atmospheric pollutants and their sources; impact of pollutants on health and environment

  • The Earth’s water resources and methods for potable water; purification and treatment techniques

Connections to prior learning and real-world relevance

  • The subject content builds on KS3 and links to potential A-level study; emphasizes how science explains real-world phenomena, informs technology, and shapes environmental and societal decisions

  • Understanding of energy, materials, biological systems and environmental cycles supports everyday decision-making, scientific literacy, and responsible citizenship

Notes on mathematical and measurement expectations

  • The mathematical and measurement skills highlighted across appendices are essential for rigorous scientific enquiry and for performing quantitative analyses in all branches of science

  • Students should be able to apply appropriate units, convert between units, handle orders of magnitude, and interpret data with attention to precision and uncertainty

Ethical, philosophical, and practical implications

  • The content includes discussion of risks, ethics of stem cell use, genetic engineering, reproductive technologies, and environmental stewardship

  • Students are encouraged to evaluate claims critically, considering data quality, uncertainty, and broader consequences for society and the environment