Edexcel GCSE Science Glossary

Edexcel GCSE Combined Science (1SC0) – Core Glossary

This glossary is designed for Edexcel GCSE (9–1) Combined Science (1SC0). It explains key words from Biology, Chemistry and Physics in calm, clear language to support confident, neuro-inclusive revision.

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Biology Glossary (Edexcel Combined Science)

These terms link to topics such as key concepts in biology, cells and control, health and disease, plant structures, animal coordination and ecosystems.

Active transport: Movement of particles from a low to a high concentration using energy from respiration.
Active site: The part of an enzyme where the substrate fits and the reaction happens.
Aerobic respiration: Release of energy from glucose using oxygen. Word equation: glucose + oxygen → carbon dioxide + water.
Anaerobic respiration: Release of energy from glucose without oxygen, making lactic acid in muscles.
Antibody: A protein made by white blood cells that sticks to a specific antigen and helps destroy pathogens.
Antigen: A molecule on the surface of a pathogen that triggers an immune response.
Artery: Blood vessel with thick muscular walls that carries blood away from the heart at high pressure.
Bacteria: Single-celled prokaryotic organisms. Some cause disease; others are useful.
Benign tumour: A growth of abnormal cells that stays in one place and does not spread to other parts of the body.
Capillary: Very thin blood vessel where substances like oxygen and glucose diffuse in and out of cells.
Cell membrane: Thin layer surrounding the cell that controls what enters and leaves.
Cell wall: Rigid layer made of cellulose in plant and algal cells that supports and strengthens the cell.
Chloroplast: Plant cell organelle containing chlorophyll where photosynthesis happens.
Communicable disease: A disease that can spread between people or animals, caused by pathogens.
Diffusion: Net movement of particles from an area of higher concentration to an area of lower concentration.
Enzyme: A biological catalyst made of protein that speeds up chemical reactions in the body.
Eukaryotic cell: Cell that has a nucleus and membrane-bound organelles, e.g. animal and plant cells.
Prokaryotic cell: Smaller cell without a nucleus, e.g. bacterial cell.
Glucose: A simple sugar used in respiration and made in photosynthesis.
Haemoglobin: Red pigment in red blood cells that carries oxygen.
Homeostasis: Maintaining a stable internal environment in the body.
Hormone: Chemical messenger released into the blood by glands and carried to target organs.
Mitochondria: Organelles where most aerobic respiration happens, releasing energy for the cell.
Mitosis: Type of cell division that makes two identical daughter cells for growth or repair.
Non-communicable disease: A disease that cannot be passed from person to person, e.g. coronary heart disease.
Osmosis: Diffusion of water through a partially permeable membrane from high to low water concentration.
Pathogen: Microorganism that causes disease, such as certain bacteria, viruses, fungi or protists.
Photosynthesis: Process in plants that uses light energy to convert carbon dioxide and water into glucose and oxygen.
Plasma: Liquid part of the blood that carries cells and dissolved substances.
Platelets: Cell fragments in the blood that help with clotting at wounds.
Respiration: Process that releases energy from food molecules in cells.
Vaccination: Giving a dead, weakened, or part of a pathogen to stimulate immunity.
Vector (disease): An organism that carries a pathogen from one host to another, e.g. a mosquito.

Chemistry Glossary (Edexcel Combined Science)

These terms support topics such as key concepts in chemistry, states of matter and mixtures, chemical changes, extracting metals, rates, fuels and Earth science.

Acid: A substance that forms H⁺ ions in solution and has a pH less than 7.
Alkali: A soluble base that forms OH⁻ ions in solution and has a pH greater than 7.
Alloy: A mixture of a metal with other elements to improve properties.
Atom: Smallest part of an element that can still be recognised as that element.
Base: Substance that can neutralise an acid, forming a salt and water.
Catalyst: Substance that speeds up a reaction without being used up.
Concentration: Amount of solute dissolved in a given volume of solution.
Compound: Substance made when atoms of two or more elements are chemically bonded.
Covalent bond: Bond formed when atoms share pairs of electrons.
Crude oil: Mixture of many hydrocarbons, mainly alkanes, formed from ancient biomass.
Electrolysis: Decomposition of an ionic compound using electricity.
Element: Pure substance made of only one type of atom.
Endothermic reaction: Reaction that takes in energy from the surroundings, causing a temperature decrease.
Exothermic reaction: Reaction that releases energy to the surroundings, causing a temperature increase.
Formula: Representation of a substance using chemical symbols, e.g. H₂O.
Group (periodic table): Vertical column of elements that have similar chemical properties.
Hydrocarbon: Compound made only of hydrogen and carbon atoms.
Ion: Charged particle formed when atoms or groups of atoms lose or gain electrons.
Ionic bond: Electrostatic attraction between oppositely charged ions.
Isotope: Atoms of the same element with the same number of protons but different numbers of neutrons.
Mixture: Two or more substances not chemically bonded and easily separated.
Neutralisation: Reaction between an acid and a base to form a salt and water.
Oxidation: Reaction involving gain of oxygen or loss of electrons.
Periodic table: Chart of elements arranged in order of atomic (proton) number.
pH scale: Scale from 0 to 14 showing how acidic or alkaline a solution is.
Product: Substance made in a chemical reaction.
Reactant: Starting substance in a chemical reaction.
Reduction: Reaction involving loss of oxygen or gain of electrons.
Relative formula mass (Mr): Sum of the relative atomic masses of all atoms in a formula; unit-less.
State symbol: Letter in brackets after a formula showing physical state: (s), (l), (g), (aq).
Thermal decomposition: Breaking down a compound using heat.

Physics Glossary (Edexcel Combined Science)

These terms support topics such as key concepts of physics, motion and forces, conservation of energy, waves, electricity, radioactivity, particle model, magnetism and more.

Acceleration: Change in velocity per second. Measured in m/s².
Amplitude: Maximum displacement of a wave from its rest position.
Atomic number: Number of protons in the nucleus of an atom.
Beta radiation: Radiation made of fast-moving electrons from the nucleus.
Current: Flow of electric charge per second. Measured in amperes (A).
Density: Mass per unit volume of a substance. Density = mass ÷ volume.
Efficiency: Useful energy output ÷ total energy input (often as a percentage).
Energy store: Way energy is kept, e.g. kinetic, gravitational, thermal, elastic, chemical.
Frequency: Number of wave cycles per second. Measured in hertz (Hz).
Gravitational field strength: Force on 1 kg in a gravitational field. Measured in N/kg.
Half-life: Time for the activity or number of radioactive nuclei to halve.
Joule (J): Unit of energy and work.
Kinetic energy: Energy an object has because it is moving.
Longitudinal wave: Wave where vibrations are parallel to the direction of energy transfer, e.g. sound.
Magnetic field: Region where a magnetic material or moving charge experiences a force.
Mass: Amount of matter in an object. Measured in kilograms (kg).
Newton’s first law: If the resultant force is zero, an object stays at rest or moves at constant velocity.
Potential difference (voltage): Energy transferred per coulomb of charge. Measured in volts (V).
Power: Rate of energy transfer or work done per second. Measured in watts (W).
Resistance: How much a component opposes current. Measured in ohms (Ω).
Resultant force: Single force that has the same effect as all the forces acting on an object.
Scalar quantity: Quantity with magnitude only, e.g. speed, distance, mass.
Vector quantity: Quantity with magnitude and direction, e.g. velocity, force.
Specific heat capacity: Energy needed to raise the temperature of 1 kg of a substance by 1 °C.
Speed: Distance travelled per unit time. Measured in m/s.
Transverse wave: Wave where vibrations are at right angles to the direction of energy transfer, e.g. light.
Velocity: Speed in a given direction.
Work done: Energy transferred when a force moves an object. Work = force × distance.

Working Scientifically & Exam Language

These words appear in practical work and exam questions across all three sciences.

Accuracy: How close a measurement is to the true value.
Anomalous result: A result that does not fit the pattern of the other data.
Calibration: Checking or setting a measuring instrument using known values.
Control variable: A variable that must be kept the same to make a test fair.
Dependent variable: The variable that is measured in an investigation.
Independent variable: The variable that is changed on purpose in an investigation.
Hypothesis: A testable idea or prediction about what you think will happen.
Precision: How close repeated measurements are to each other.
Prediction: Statement suggesting what will happen in a new situation, based on evidence.
Reliability: How consistent results are when an investigation is repeated.
Repeatable: When the same person gets similar results using the same method and equipment.
Reproducible: When different people or methods give similar results.
Resolution: The smallest change a measuring instrument can detect.
Risk assessment: Identifying possible dangers and how to reduce them before a practical.
Systematic error: Error that shifts all results in one direction, often due to faulty equipment or method.
Random error: Error that causes results to vary in an unpredictable way from measurement to measurement.
Uncertainty: The range within which the true value is expected to lie.

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This glossary is designed to support Edexcel GCSE (9–1) Combined Science (1SC0). It is for learning support only and does not replace the official specification or exam materials.