Combined Science GCSE
Combined Science GCSE glossary
113 key terms for Combined Science GCSE, A to Z, each linked to the topic pages that use it.
A
- Abiotic Factor
- A non-living, physical factor that can affect the size or distribution of a population (e.g., light, temperature).Pearson Edexcel
- Alternating Current (a.c.)
- An electric current that continuously changes direction.Pearson Edexcel
- Alveoli
- Tiny air sacs in the lungs adapted for efficient gas exchange between the air and the blood.Pearson Edexcel
- Amplitude
- The maximum displacement of a point on a wave away from its undisturbed (equilibrium) position.Pearson Edexcel
- Angle of Incidence
- The angle between the incident ray and the normal line.Pearson Edexcel
- Antibiotic
- A medicine that helps to cure bacterial disease by killing infective bacteria inside the body.Pearson Edexcel
B
- Base
- A substance that can neutralise an acid.Pearson Edexcel
- Base Unit
- One of the seven fundamental units of the SI system from which all other units are derived.Pearson Edexcel
- Biodiversity
- The variety of all the different species of organisms on earth, or within an ecosystem.Pearson Edexcel
- Biotic Factor
- A living factor that affects the size or distribution of a population (e.g., predation, competition, disease).Pearson Edexcel
C
- Capillary
- The smallest blood vessels, with walls one cell thick, where the exchange of substances with tissues occurs.Pearson Edexcel
- Cardiac Output
- The total volume of blood pumped by a ventricle every minute.Pearson Edexcel
- Clinical trial
- Medical experiments carried out on human volunteers and patients to test the safety, dosage, and efficacy of a new drug.Pearson Edexcel
- Closed System
- A system in which no energy transfers take place out of or into the energy stores of the system.Pearson Edexcel
- Conservation of Energy
- The principle that energy cannot be created or destroyed, only transferred from one store to another.Pearson Edexcel
- Contact Force
- A force that acts only when two objects are physically touching.Pearson Edexcel
- Contamination
- The unwanted presence of materials containing radioactive atoms on other materials.Pearson Edexcel
D
- Decomposition
- The breakdown of dead matter and waste by microorganisms (bacteria and fungi).Pearson Edexcel
- Differentiation
- The process by which a cell changes to become specialised for its job.Pearson Edexcel
- Diffusion
- The net movement of particles from an area of higher concentration to an area of lower concentration.Pearson Edexcel
- Diode
- A component that only allows current to flow in one direction.Pearson Edexcel
- Direct Current (d.c.)
- An electric current that flows in one direction only.Pearson Edexcel
- Displacement
- A vector quantity representing the straight-line distance from the starting position to the final position, in a given direction.Pearson Edexcel
- Dissipated Energy
- Energy that is transferred to less useful stores, usually the thermal store of the surroundings.Pearson Edexcel
- Dissipation
- The process where energy is transferred to the thermal store of the surroundings, becoming less useful.Pearson Edexcel
- Distance
- A scalar quantity representing the total length of the path travelled by an object.Pearson Edexcel
- Dosimeter
- A device worn by personnel working with radiation to measure and monitor their cumulative radiation dose.Pearson Edexcel
- Double Circulatory System
- A circulatory system where blood passes through the heart twice for every one complete circuit of the body.Pearson Edexcel
E
- Ecosystem
- The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.Pearson Edexcel
- Efficacy
- How effective a drug is at preventing or curing the disease, or making the patient feel better.Pearson Edexcel
- Efficiency
- The ratio of useful energy output to total energy input.Pearson Edexcel
- Elastic Deformation
- When an object returns to its original shape and length after the deforming force is removed.Pearson Edexcel
- Elastic Potential Energy
- The energy stored in an elastic object when work is done on it to change its shape.Pearson Edexcel
- Electromagnetic Induction
- The production of a potential difference (voltage) across a conductor when it is exposed to a changing magnetic field.Pearson Edexcel
- Equilibrium
- The state of an object when the resultant force acting on it is zero.Pearson Edexcel
- Eukaryotic Cell
- A complex cell that contains a nucleus and membrane-bound organelles (e.g., animal and plant cells).Pearson Edexcel
- Excess
- More than the amount required to react completely with the limiting reactant.Pearson Edexcel
F
G
H
- Homeostasis
- The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.Pearson Edexcel
- Hooke's Law
- The extension of an elastic object is directly proportional to the force applied, provided the limit of proportionality is not exceeded.Pearson Edexcel
I
- Induced magnet
- A material that becomes a magnet when it is placed in a magnetic field.Pearson Edexcel
- Inelastic (Plastic) Deformation
- When an object does not return to its original shape and length after the deforming force is removed.Pearson Edexcel
- Insulin
- A hormone produced by the pancreas that lowers blood glucose concentration by causing cells to take in glucose and the liver to convert glucose to glycogen.Pearson Edexcel
- Intermolecular Forces
- The attractive forces between molecules that hold them together in solid and liquid states.Pearson Edexcel
- Internal Energy
- The total kinetic and potential energy of all the particles that make up a system.Pearson Edexcel
- Ionisation
- The process where radiation knocks electrons out of atoms, turning them into charged ions.Pearson Edexcel
- Ionising Radiation
- Radiation with enough energy to knock electrons off atoms, potentially causing cell mutation and cancer.Pearson Edexcel
- Irradiation
- The process of exposing an object to nuclear radiation.Pearson Edexcel
J
- Justification
- The medical principle that the benefits of a radiation procedure must outweigh the risks.Pearson Edexcel
K
- Kinetic Energy (of particles)
- The energy particles have due to their motion or vibration.Pearson Edexcel
L
- Lignin
- A tough polymer that strengthens the cell walls of xylem vessels, providing support to the plant.Pearson Edexcel
- Limit of Proportionality
- The point beyond which Hooke's Law is no longer true; extension is no longer directly proportional to the applied force.Pearson Edexcel
- Limiting factor
- A factor that is in short supply and therefore restricts the rate of a chemical reaction.Pearson Edexcel
- Longitudinal Wave
- A wave where the oscillations are parallel to the direction of energy transfer.Pearson Edexcel
M
- Magnetic field
- The region around a magnet where a force acts on another magnet or on a magnetic material.Pearson Edexcel
- Magnetic flux density
- A measure of the strength of a magnetic field, measured in Tesla (T).Pearson Edexcel
- Magnitude
- The size or numerical value of a physical quantity.Pearson Edexcel
- Motor effect
- The force experienced by a current-carrying conductor when placed in a magnetic field.Pearson Edexcel
- Mutation
- A change in the genetic material (DNA) of a cell, which can be caused by ionising radiation.Pearson Edexcel
N
- National Grid
- The network of cables and transformers used to transfer electrical power from power stations to consumers.Pearson Edexcel
- Neutralisation
- A chemical reaction between an acid and a base to produce a salt and water.Pearson Edexcel
- Nitrification
- The process by which bacteria convert ammonia into nitrites and then into nitrates in the soil.Pearson Edexcel
- Non-Contact Force
- A force that acts between two objects that are not physically touching.Pearson Edexcel
- Normal Line
- An imaginary dashed line drawn at 90 degrees to the boundary surface at the point of incidence.Pearson Edexcel
O
- Order of Magnitude
- An estimate of size expressed as a power of ten.Pearson Edexcel
- Organelle
- A sub-cellular structure that has a specific function within the cell.Pearson Edexcel
P
- Parallel Circuit
- A circuit in which components are connected on separate branches, providing multiple paths for the current.Pearson Edexcel
- Period
- The time taken for one complete wave to pass a fixed point.Pearson Edexcel
- Permanent magnet
- A magnet that produces its own magnetic field continuously.Pearson Edexcel
- Photosynthesis
- An endothermic reaction in which energy is transferred from the environment to chloroplasts by light, converting carbon dioxide and water into glucose and…Pearson Edexcel
- Placebo
- A substance that looks exactly like the real drug but does not contain the active ingredient, used as a control in trials.Pearson Edexcel
- Plasmid
- A small ring of extra DNA found in bacterial cells.Pearson Edexcel
- Potential Difference
- The energy transferred per unit charge passed.Pearson Edexcel
- Power
- The rate at which work is done or the rate at which energy is transferred.Pearson Edexcel
- Preclinical testing
- Testing of a new drug in a laboratory using cells, tissues, and live animals before it is tested on humans.Pearson Edexcel
- Prefix
- A letter placed before a unit symbol to indicate a decimal multiplier (e.g., 'k' in 'kg' means $\times 1000$).Pearson Edexcel
- Prokaryotic Cell
- A simple, smaller cell that lacks a nucleus and membrane-bound organelles (e.g., bacterial cells).Pearson Edexcel
R
- Refraction
- The change in direction of a wave as it passes from one medium to another, caused by a change in wave speed.Pearson Edexcel
- Residue
- The solid substance left behind on the filter paper after filtration.Pearson Edexcel
- Resolution
- The ability to distinguish between two separate points.Pearson Edexcel
- Resultant Force
- A single force that has the same effect as all the original forces acting together.Pearson Edexcel
S
- Scalar Quantity
- A physical quantity that has magnitude (size) only.Pearson Edexcel
- Series Circuit
- A circuit in which components are connected end-to-end, providing only one path for the current.Pearson Edexcel
- SI Units
- The International System of Units; a globally agreed system of measurements used in science.Pearson Edexcel
- Significant Figures
- The digits in a number that carry meaning contributing to its measurement resolution or precision.Pearson Edexcel
- Solenoid
- A coil of wire carrying an electric current, which produces a magnetic field similar to a bar magnet.Pearson Edexcel
- Specific Heat Capacity
- The amount of energy required to raise the temperature of one kilogram of a substance by one degree Celsius.Pearson Edexcel
- Specific Latent Heat of Fusion
- The amount of energy required to change the state of one kilogram of a substance from solid to liquid with no change in temperature.Pearson Edexcel
- Spring Constant (k)
- A measure of the stiffness of a spring, representing the force required per unit of extension (N/m).Pearson Edexcel
- Standard Form
- A mathematical notation used to express very large or very small numbers as a product of a number between 1 and 10, and a power of 10.Pearson Edexcel
- Step-down Transformer
- A transformer that decreases potential difference (has fewer turns on the secondary coil than the primary).Pearson Edexcel
- Step-up Transformer
- A transformer that increases potential difference (has more turns on the secondary coil than the primary).Pearson Edexcel
- Stomata
- Tiny pores on the surface of a leaf (usually the underside) that allow for gas exchange and water loss.Pearson Edexcel
- Surface Area to Volume Ratio
- The surface area of an organism divided by its volume, which determines the efficiency of diffusion across its surface.Pearson Edexcel
T
- Thermal Conductivity
- A measure of how quickly energy is transferred through a material by conduction.Pearson Edexcel
- Thermal Insulator
- A material that does not easily allow the transfer of thermal energy.Pearson Edexcel
- Thermistor
- A resistor whose resistance decreases as temperature increases.Pearson Edexcel
- Toxicity
- How harmful or poisonous a drug is, and whether it has severe side effects.Pearson Edexcel
- Translocation
- The movement of dissolved sugars (sucrose) from the leaves to the rest of the plant through phloem tissue.Pearson Edexcel
- Transpiration
- The loss of water vapour from the leaves of a plant, primarily through the stomata.Pearson Edexcel
- Transverse Wave
- A wave where the oscillations (vibrations) are perpendicular to the direction of energy transfer.Pearson Edexcel
- Type 1 Diabetes
- A disorder in which the pancreas fails to produce sufficient insulin, characterised by uncontrolled high blood glucose levels.Pearson Edexcel
- Type 2 Diabetes
- A disorder where the body cells no longer respond to the insulin produced by the pancreas, strongly linked to obesity.Pearson Edexcel
V
- Vacuum
- A space completely devoid of matter (particles).Pearson Edexcel
- Vector Quantity
- A physical quantity that has both magnitude and direction.Pearson Edexcel
- Velocity
- A vector quantity representing the speed of an object in a stated direction.Pearson Edexcel
W
- Water of crystallisation
- Water molecules that are chemically bonded into the crystalline structure of a salt.Pearson Edexcel
- Watt
- The unit of power, equivalent to a transfer of one Joule per second (1 W = 1 J/s).Pearson Edexcel
- Wavelength
- The distance from a point on one wave to the equivalent point on the adjacent wave (e.g., crest to crest).Pearson Edexcel
- Work Done
- Another way of saying energy transferred.Pearson Edexcel
Where these terms come from
Each definition is one we publish on a Combined Science GCSE topic page or study guide. Open a term to see how each exam board words it and which topic it belongs to. For the full course, go to Combined Science revision or the glossary for every subject.
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