Combined Science: Trilogy

Why new evidence can change models and theories

Using data to support or challenge a claim

Scientific models: what they are and why we use them

Drawing and interpreting scientific diagrams and models

Using models to make predictions (and spotting limitations)

Ethical issues in science: how to argue a viewpoint

Science in society: weighing up benefits, risks, and impacts

Risk in science: hazard vs risk, perceived vs measured risk

Peer review: why it matters and what it does

Science in the media: spotting oversimplification and bias

Writing testable hypotheses from observations

Identifying independent, dependent, and control variables

Planning a valid method (controls, repeats, range, resolution)

Accuracy, precision, repeatability, reproducibility

Random vs systematic error (and how to reduce them)

Sampling: when it’s needed and how to make it representative

Recording data: tables, units, headings, significant figures

Graph choice: bar charts vs line graphs vs scatter graphs

Drawing best-fit lines and curves (and using them to conclude)

Making conclusions that link directly to evidence

Evaluating methods: limitations, improvements, next steps

Communicating findings clearly (methods, results, conclusions)

Standard form (including converting and calculating)

Ratios, fractions, and percentages in science contexts

Estimating answers to check for mistakes

Significant figures (rounding and “too precise” answers)

Finding means, mode, and median in datasets

Frequency tables, bar charts, and histograms

Sampling in biology data (bias, sample size, random sampling)

Simple probability in biology contexts

Scatter graphs and correlation (biology/physics)

Order of magnitude calculations

Rearranging equations (changing the subject)

Substituting values with correct units (chemistry/physics)

Solving simple equations (biology/physics)

Converting between tables, graphs, and sentences

Understanding y = mx + c in practical graphs

Gradient and intercept from linear graphs

Tangents to curves to find rate (chemistry/physics)

Area under a graph by counting squares (physics)

Angles in degrees (physics)

Visualising 2D/3D shapes in science diagrams

Area, surface area, and volume calculations

Required practical: Osmosis in plant tissue (mass change vs concentration)

Required practical: Food tests (Benedict’s, iodine, Biuret, lipids)

Required practical: Enzymes (effect of pH on amylase using sampling)

Required practical: Photosynthesis (light intensity vs rate using pondweed)

Required practical: Reaction time (plan and carry out a human investigation)

Required practical: Fieldwork sampling (population size + distribution factor)

Required practical: Making a soluble salt (from insoluble base/carbonate)

Required practical: Electrolysis of aqueous solutions (inert electrodes)

Required practical: Temperature changes in reactions (exothermic/endothermic)

Required practical: Rates (gas volume and colour/turbidity methods)

Required practical: Chromatography (separation + Rf values)

Required practical: Water analysis and purification (pH, solids, distillation)

Required practical: Specific heat capacity (link energy change to temperature rise)

Required practical: Resistance (wire length; series vs parallel resistors)

Required practical: I–V characteristics (lamp, diode, resistor)

Required practical: Density (regular/irregular solids + liquids)

Required practical: Force and extension (spring)

Required practical: Newton’s second law (force, mass, acceleration)

Required practical: Waves (measuring wavelength, frequency, speed)

Required practical: Infrared radiation (absorption/radiation vs surface)

Eukaryotic vs prokaryotic cells

Animal vs plant cells: key differences

Subcellular structures and their functions

Specialised cells: structure linked to function

Levels of organisation: cells to tissues to organs

Using a light microscope safely and effectively

Magnification calculations (image size vs actual size)

Scale bars and estimating cell size

Diffusion: what it is and what affects rate

Osmosis: movement of water across membranes

Active transport: moving substances against a gradient

Mitosis and the cell cycle (why it matters)

Stem cells: what they are and potential uses (with ethics)

Digestive enzymes: amylase, protease, lipase

Enzyme action and “active site” idea

Effects of temperature, pH, and concentration on enzymes

Testing for biological molecules (food tests recap + interpretation)

The circulatory system: heart, vessels, double circulation

The pathway of blood through the heart

Blood components and their functions

Coronary heart disease: causes and risk factors

Non-communicable diseases: risk factors and data links

Cancer: benign vs malignant, how tumours form

Plant tissues (xylem and phloem) and transport

Transpiration: what drives it and what affects it

Leaf adaptations for gas exchange and photosynthesis

Root hair cells and water/mineral uptake

Pathogens: bacteria, viruses, fungi, protists

Common disease examples and how they spread

Human defence barriers (skin, mucus, cilia, stomach acid)

White blood cells: phagocytosis and immune response

Antibodies and antigens (specificity)

Vaccination: how it works and herd immunity

Antibiotics: treating bacteria (not viruses)

Antibiotic resistance and why it spreads

Drug discovery: testing, trials, and peer review

Monoclonal antibodies: what they are used for

Plant diseases: pathogens and plant defences

Physical plant defences and chemical plant defences

Rate of photosynthesis: limiting factors (light, CO₂, temperature)

Interpreting photosynthesis investigations and graphs

How plants use glucose (storage and building materials)

Respiration as a reaction that releases energy

Aerobic respiration: equation and energy release

Anaerobic respiration in muscles: equation and consequences

Oxygen debt and recovery after exercise

Metabolism: energy use in the body (overview)

Comparing photosynthesis and respiration

Control systems: receptors, coordination centres, effectors

The nervous system: CNS and peripheral nerves

Reflex arcs (stimulus → response pathway)

Synapses (signal transmission idea)

The endocrine system: hormones and target organs

Adrenaline: fight-or-flight effects

Blood glucose control: insulin and glucagon

Diabetes: Type 1 vs Type 2 (causes and treatments)

Thermoregulation: sweating, shivering, vasodilation/constriction

The kidneys: filtration, reabsorption, and urine formation

Kidney failure and dialysis (basic comparison)

Reproduction: menstrual cycle and hormone roles

Contraception: barrier vs hormonal (benefits and drawbacks)

Plant hormones: tropisms and simple plant responses

Base pairs and the genetic code (overview)

Mitosis vs meiosis (purpose and outcomes)

Sexual vs asexual reproduction (pros/cons)

Genetic inheritance: alleles, genotype, phenotype

Dominant vs recessive alleles

Punnett squares for monohybrid crosses

Sex determination (XX/XY)

Inherited disorders (example-based understanding)

Variation: genetic vs environmental causes

Mutation: what it is and potential effects

Evolution by natural selection (step-by-step)

Fossils as evidence for evolution (and limitations)

Speciation and extinction (overview)

Selective breeding: method, benefits, drawbacks

Genetic engineering: what it is used for (with ethics)

Biotic vs abiotic factors affecting organisms

Food chains and trophic levels

Food webs and interdependence

Pyramids of biomass (what they show)

Biomass transfer and energy loss between trophic levels

Decomposition: role of microorganisms and decay conditions

The carbon cycle (processes and stores)

The water cycle (processes and stores)

Biodiversity: what it means and why it matters

Human impacts: land use change and habitat loss

Pollution: air, water, and land (examples and effects)

Global warming and climate change (basic mechanisms)

Maintaining biodiversity: conservation strategies

Measuring biodiversity and populations (sampling methods)

Evaluating ecological data and drawing conclusions

Mixtures vs pure substances

The structure of the atom (protons, neutrons, electrons)

Atomic number and mass number

Isotopes and why they exist

Relative atomic mass (idea and interpretation)

Electron shells and electronic structure (simple model)

Periodic table layout: groups and periods

Metals vs non-metals (properties overview)

Group 1 alkali metals: key trends and reactions

Group 7 halogens: key trends and displacement

Group 0 noble gases: why they’re unreactive

Transition metals: typical properties and uses

Ionic bonding: ions and electrostatic attraction

Covalent bonding: sharing electrons

Metallic bonding: “sea of electrons” model

Dot-and-cross diagrams (ionic and covalent)

Simple molecular substances: melting/boiling and conductivity

Giant ionic lattices: properties and why they occur

Giant covalent structures: diamond and graphite

Graphene and fullerenes (properties and uses)

Polymers: structure and basic properties

Nanoparticles: what they are and why properties change

States of matter and particle arrangement

Changes of state and energy transfer (particle model)

Balancing symbol equations

Conservation of mass (and gases leaving the system)

Relative atomic mass and Mr calculations

The mole concept (linking particles to amount)

Moles from mass and Mr

Mass from moles and Mr

Concentration in g/dm³ and mol/dm³ (core methods)

Using balanced equations for reacting mass calculations

Percentage yield (meaning and calculation)

Atom economy (meaning and calculation)

Limiting reactants (idea and simple identification)

Displacement reactions (metals)

Oxidation and reduction (electron transfer idea)

Acids and alkalis: core properties

pH scale and indicators

Neutralisation: making salts and water

Making soluble salts (method + purity)

Making insoluble salts (precipitation)

Electrolysis basics: ions and electrodes

Electrolysis of molten ionic compounds

Electrolysis of aqueous solutions (products and rules)

Extracting metals (basic reduction idea)

Energy level diagrams (reaction profiles)

Activation energy and why it matters

Catalysts and how they affect activation energy

Bond breaking and bond making (energy ideas)

Using bond energies to estimate energy change

Measuring temperature change in reactions safely

Evaluating temperature-change practicals (errors and improvements)

Collision theory basics

Effect of temperature on rate

Effect of concentration/pressure on rate

Effect of surface area on rate

Catalysts and reaction rate

Measuring rate: gas volume method

Measuring rate: colour/turbidity method

Drawing and interpreting rate graphs

Reversible reactions and dynamic equilibrium

Changing conditions and equilibrium position

Le Chatelier’s principle (applied examples)

Fractional distillation and boiling range

Properties of fractions (viscosity, volatility, flammability)

Alkanes vs alkenes (structures and general formulae)

Cracking: why it’s done and what it produces

Polymerisation (addition polymers)

Ethanol: production by fermentation

Ethanol: production by hydration (overview)

Combustion of hydrocarbons (complete vs incomplete)

Pollutants from combustion and how to reduce them

Chromatography: setting up and interpreting results

Rf values: calculation and comparison

Gas tests (H₂, O₂, CO₂, Cl₂)

Flame tests for metal ions (overview)

Precipitation tests for common ions (overview)

Instrumental methods: what they can show (overview)

Analysing and purifying water samples (pH, solids, distillation)

How the atmosphere changed over time

Greenhouse gases and the greenhouse effect

Evidence for climate change (data patterns)

Human activities increasing greenhouse gases

Atmospheric pollutants: NOx, SO₂, particulates, CO

Acid rain: causes and impacts

Reducing pollution (catalytic converters and regulations)