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Science KS3 Vocab

2 Enquiry processes

2.1 Analyse Patterns

Linear relationship

When two variables are graphed and show a straight line which goes through the origin, and they can be called directly proportional.


A piece of data that does not fit the pattern.


An average of a set of data, calculated by adding all the values and dividing by the number of values.

2.2 Discuss Limitations

Experimental error

Variations in measurements, owing to the method, measurement techniques or the instrument.

Random and systematic error

Random errors are when the same quantity is measured and inconsistent values obtained. Systematic errors arise from an inaccuracy in the system and give rise to errors of the same value.

2.3 Draw Conclusions

Secondary data

Results that have already been collected by another person.

Real difference

There is a real difference between two means if their ranges do not overlap much.

2.4 Present Data

Continuous variable

Has values that can be any number.

Discontinuous variable

Has values that are words or discrete numbers.

Bar chart/column graph

Displays the values of categories.

Line graph

Shows the relationship between two continuous variables.

Pie chart

Shows the proportions or percentages that make up a whole.

Line of best fit

A straight or curved line drawn to show the pattern of data points

2.6 Construct Explanations


Information gathered by your senses.


Information from an observation or experiment that supports an idea.

2.7 Critique Claims


A statement that says something is true.


The facts, scientific ideas, data or conclusions that support the claim


Your ideas about what the evidence means, in the form of an argument for or against the claim.

2.7 Critique Claims


A statement that says something is true.


The facts, scientific ideas, data or conclusions that support the claim


Your ideas about what the evidence means, in the form of an argument for or against the claim.

2.9 Collect Data


The maximum and minimum values of a variable.


The gap between the values of the independent variable

Control group

Those that are not exposed to the factor being tested.


When repeat readings are close together.

2.10 Devise Questions

Scientific enquiries

Different ways to investigate including observation over time, fair test and pattern seeking.


A factor that can be changed, measured and controlled.

Independent variable

What you change in an investigation to see how it affects the dependent variable

Dependent variable

What you measure or observe in an investigation


A relationship between variables where one increases or decreases as the other increases.

2.11 Plan Variables

Control variable

One that remains unchanged or is held constant to stop it affecting the dependant variable.

2.12 Test Hypotheses


An explanation you can test which includes a reason and a ‘science idea’.


Information gathered by your senses.


What you think will happen in an experiment

2.13 Estimate Risks


How likely something is to be harmful


A situation that presents a threat to people


Something good or helpful.

Control measure

An action taken to remove the hazard or to reduce the exposure to it

2.16 Interrogate Sources

Peer reviewed

The checking of research by other scientists


When an experimenter affects the outcome, or when a journalist favours a point of view


Organisation or person that pays for scientific research


Magazine which publishes science research for others to read.

3.1 Forces

3.1.1 Gravity


The force of gravity on an object (N)

Non-contact force

One that acts without direct contact.


The amount of stuff in an object (kg)

Gravitational field strength, g

The force from gravity on 1 kg (N/kg).


The area where other objects feel a gravitational force.

3.1.2 Contact Forces


State of an object when opposing forces are balanced.


Changing shape due to a force.

Linear relationship

When two variables are graphed and show a straight line which goes through the origin, and they can be called proportional.


Unit for measuring forces (N).

Resultant force

Single force which can replace all the forces acting on an object and have the same effect


Force opposing motion which is caused by the interaction of surfaces moving over one another. It is called ‘drag’ if one is a fluid.


Force extending or pulling apart.


Force squashing or pushing together.

Contact force

One that acts by direct contact

3.1.3 Pressure


A substance with no fixed shape, a gas or a liquid.


The ratio of force to surface area, in N/m2, and how it causes stresses in solids.


The upward force that a liquid or gas exerts on a body floating in it.

Atmospheric pressure

The pressure caused by the weight of the air above a surface.

3.1.4 Speed


How much distance is covered in how much time.

Average speed

The overall distance travelled divided by overall time for a journey.

Relative motion

Different observers judge speeds differently if they are in motion too, so an object’s speed is relative to the observer’s speed.


How quickly speed increases or decreases.

3.2 Electromagnets

3.2.1 Voltage and Resistance

Potential difference (voltage)

The amount of energy shifted from the battery to the moving charge, or from the charge to circuit components, in volts (V).


A property of a component, making it difficult for charge to pass through, in ohms (Ω).

Electrical conductor

A material that allows current to flow through it easily, and has a low resistance.

Electrical insulator

A material that does not allow current to flow easily, and has a high resistance.

3.2.2 Current

Negatively charged

An object that has gained electrons as a result of the charging process.

Positively charged

An object that has lost electrons as a result of the charging process.


Tiny particles which are part of atoms and carry a negative charge.

Charged up

When materials are rubbed together, electrons move from one surface to the other.

Electrostatic force

Non-contact force between two charged objects.


Flow of electric charge, in amperes (A).

In series

If components in a circuit are on the same loop.

In parallel

If some components are on separate loops

3.2.3 Electromagnets


A non-permanent magnet turned on and off by controlling the current through it.


Wire wound into a tight coil, part of an electromagnet.


Soft iron metal which the solenoid is wrapped around.

3.2.4 Magnetism

Magnetic force

Non-contact force from a magnet on a magnetic material.

Permanent magnet

An object that is magnetic all of the time.

Magnetic poles

The ends of a magnetic field, called north-seeking (N) and south-seeking poles (S).

3.3 Energy

3.3.1 Energy Costs


How quickly energy is transferred by a device (watts).

Energy resource

Something with stored energy that can be released in a useful way.


An energy resource that cannot be replaced and will be used up.


An energy resource that can be replaced and will not run out. Examples are solar, wind, waves, geothermal and biomass.

Fossil fuels

Non-renewable energy resources formed from the remains of ancient plants or animals. Examples are coal, crude oil and natural gas.

3.3.2 Energy Transfer

Thermal energy store

Filled when an object is warmed up.

Chemical energy store

Emptied during chemical reactions when energy is transferred to surroundings

Kinetic energy store

Filled when an object speeds up

Gravitational potential energy store

Filled when an object is raised.

Elastic energy store

Filled when a material is stretched or compressed.


Become spread out wastefully

3.3.3 Work


The transfer of energy when a force moves an object, in joules.


A type of machine which is a rigid bar that pivots about a point.

Input force

The force you apply to a machine.

Output force

The force that is applied to the object moved by the machine.


The distance an object moves from its original position.


When an elastic object is stretched or squashed, which requires work.

3.3.4 Heating and Cooling

Thermal conductor

Material that allows heat to move quickly through it.

Thermal insulator

Material that only allows heat to travel slowly through it.


A measure of the motion and energy of the particles.

Thermal energy

The quantity of energy stored in a substance due to the vibration of its particles.


Transfer of thermal energy by the vibration of particles.


Transfer of thermal energy when particles in a heated fluid rise.


Transfer of thermal energy as a wave.

3.4 Waves

3.4.1 Sound


A back and forth motion that repeats

Longitudinal wave

Where the direction of vibration is the same as that of the wave.


How loud or quiet a sound is, in decibels (dB).


How low or high a sound is. A low (high) pitch sound has a low (high) frequency.


The maximum amount of vibration, measured from the middle position of the wave, in metres.


Distance between two corresponding points on a wave, in metres.


The number of waves produced in one second, in hertz.


A space with no particles of matter in it.


Device for viewing patterns of sound waves that have been turned into electrical current.


When energy is transferred from sound to a material.

Auditory range

The lowest and highest frequencies that a type of animal can hear.


Reflection of sound waves from a surface back to the listener.

3.4.2 Light

Incident ray

The incoming ray

Reflected ray

The outgoing ray

Normal line

From which angles are measured, at right angles to the surface.

Angle of reflection

Between the normal and reflected ray.

Angle of incidence

Between the normal and incident ray.


Change in the direction of light going from one material into another.


When energy is transferred from light to a material.


When light bounces off an object in all directions.


A material that allows all light to pass through it.


A material that allows some light to pass through it.


A material that allows no light to pass through it.

Convex lens

A lens that is thicker in the middle which bends light rays towards each other.

Concave lens

A lens that is thinner in the middle which spreads out light rays.


Layer at the back of the eye with light detecting cells and where image is formed.

3.4.3 Wave Effects


Sound waves with frequencies higher than the human auditory range.

Ultraviolet (UV)

Waves with frequencies higher than light, which human eyes cannot detect.


Turns the pressure wave of sound hitting it into an electrical signal.


Turns an electrical signal into a pressure wave of sound.

Pressure wave

An example is sound, which has repeating patterns of high-pressure and low-pressure regions.

3.4.4 Wave properties


Vibrations that transport energy from place to place without transporting matter.

Transverse wave

Where the direction of vibration is perpendicular to that of the wave.


Where waves travel through a medium rather than be absorbed or reflected.

3.5 Matter

3.5.1 Particle Model


A very tiny object such as an atom or molecule, too small to be seen with a microscope

Particle Model

A way to think about how substances behave in terms of small, moving particles.


The process by which particles in liquids or gases spread out through random movement from a region where there are many particles to one where there are fewer.

Gas pressure

Caused by collisions of particles with the walls of a container.


How much matter there is in a particular volume, or how close the particles are.


Change from liquid to gas at the surface of a liquid, at any temperature.


Change from liquid to a gas of all the liquid when the temperature reaches boiling point.


Change of state from gas to liquid when the temperature drops to the boiling point.


Change from solid to liquid when the temperature rises to the melting point.


Change from liquid to a solid when the temperature drops to the melting point.


Change from a solid directly into a gas

3.5.2 Separating Mixtures


A substance, normally a liquid, that dissolves another substance.


A substance that can dissolve in a liquid.


When a solute mixes completely with a solvent.


Mixture formed when a solvent dissolves a solute.

Soluble (insoluble)

Property of a substance that will (will not) dissolve in a liquid.


Maximum mass of solute that dissolves in a certain volume of solvent.

Pure substance

Single type of material with nothing mixed in.


Two or more pure substances mixed together, whose properties are different to the individual substances.


Separating substances using a filter to produce a filtrate (solution) and residue.


Separating substances by boiling and condensing liquids.


A way to separate a solid dissolved in a liquid by the liquid turning into a gas.


Used to separate different coloured substances.

3.5.3 Periodic Table

Periodic table

Shows all the elements arranged in rows and columns.

Physical properties

Features of a substance that can be observed without changing the substance itself.

Chemical properties

Features of the way a substance reacts with other substances.


Columns of the periodic table.


Rows of the periodic table.

3.5.4 Elements


What all substances are made up of, and which contain only one type of atom.


The smallest particle of an element that can exist.


Two to thousands of atoms joined together. Most non-metals exist either as small or giant molecules.


Pure substances made up of two or more elements strongly joined together.

Chemical formula

Shows the elements present in a compound and their relative proportions.


A molecule made of thousands of smaller molecules in a repeating pattern. Plastics are man- made polymers, starch is a natural polymer.

3.6 Reactions

3.6.1 Metals and Non-metals


Shiny, good conductors of electricity and heat, malleable and ductile, and usually solid at room temperature.


Dull, poor conductors of electricity and heat, brittle and usually solid or gaseous at room temperature.


Reaction where a more reactive metal takes the place of a less reactive metal in a compound


Reaction in which a substance combines with oxygen.


The tendency of a substance to undergo a chemical reaction.

3.6.2 Acids and Alkalis


Scale of acidity and alkalinity from 0 to 14.


Substances used to identify whether unknown solutions are acidic or alkaline.


A substance that neutralises an acid – those that dissolve in water are called alkalis.


A measure of the number of particles in a given volume.

3.6.3 Chemical Energy


Substances that speed up chemical reactions but are unchanged at the end.

Exothermic reaction

One in which energy is given out, usually as heat or light.

Endothermic reaction

One in which energy is taken in, usually as heat.

Chemical bond

Force that holds atoms together in molecules.

3.6.4 Types of Reaction


Stores energy in a chemical store which it can release as heat.

Chemical reaction

A change in which a new substance is formed.

Physical change

One that changes the physical properties of a substance, but no new substance is formed.


Substances that react together, shown before the arrow in an equation.


Substances formed in a chemical reaction, shown after the reaction arrow in an equation.


When the quantity of something does not change after a process takes place.

3.7 Earth

3.7.1 Earth Structure

Rock cycle

Sequence of processes where rocks change from one type to another.


The wearing down of rock by physical, chemical or biological processes.


Movement of rock by water, ice or wind (transportation).


Chemicals that rocks are made from.

Sedimentary rocks

Formed from layers of sediment, and which can contain fossils. Examples are limestone, chalk and sandstone.

Igneous rocks

Formed from cooled magma, with minerals arranged in crystals. Examples are granite, basalt and obsidian.

Metamorphic rocks

Formed from existing rocks exposed to heat and pressure over a long time. Examples are marble, slate and schist.


Layers of sedimentary rock.

3.7.2 Universe


Collection of stars held together by gravity. Our galaxy is called the Milky Way.

Light year

The distance light travels in a year (over 9 million, million kilometres).


Bodies which give out light, and which may have a solar system of planets.


Path taken by a satellite, planet or star moving around a larger body. Earth completes one orbit of the Sun every year.


Planet that orbits a star outside our solar system.

3.7.3 Climate

Global warming

The gradual increase in surface temperature of the Earth.

Fossil fuels

Remains of dead organisms that are burned as fuels, releasing carbon dioxide.

Carbon sink

Areas of vegetation, the ocean or the soil, which absorb and store carbon.

Greenhouse effect

When energy from the sun is transferred to the thermal energy store of gases in Earth’s atmosphere.

3.7.4 Earth Resources

Natural resources

Materials from the Earth which act as raw materials for making a variety of products.


Naturally occurring metal or metal compound.


Naturally occurring rock containing sufficient minerals for extraction.


Separation of a metal from a metal compound.


Processing a material so that it can be used again.


Using electricity to split up a compound into its elements.

3.8 Organisms

3.8.1 Movement


Places where bones meet

Bone marrow

Tissue found inside some bones where new blood cells are made.


Connect bones in joints


Connect muscles to bones.


Smooth tissue found at the end of bones, which reduces friction between them.

Antagonistic muscle pair

Muscles working in unison to create movement.

3.8.2 Cells


The unit of a living organism, contains parts to carry out life processes.


Living things made up of one cell


Living things made up of many types of cell.


Group of cells of one type


Group of different tissues working together to carry out a job.


One way for substances to move into and out of cells.

Structural adaptations

Special features to help a cell carry out its functions.

Cell membrane

Surrounds the cell and controls movement of substances in and out.


Contains genetic material (DNA) which controls the cell’s activities.


Area in a cell that contains liquid, and can be used by plants to keep the cell rigid and store substances.


Part of the cell where energy is released from food molecules.

Cell wall

Strengthens the cell. In plant cells it is made of cellulose.


Absorbs light energy so the plant can make food.


Jelly-like substance where most chemical processes happen.

Immune system

Protects the body against infections

Reproductive system

Produces sperm and eggs, and is where the foetus develops.

Digestive system

Breaks down and then absorbs food molecules.

Circulatory system

Transports substances around the body.

Respiratory system

Replaces oxygen and removes carbon dioxide from blood.

Muscular skeletal system

Muscles and bones working together to cause movement and support the body.

3.8.3 Breathing


The movement of air in and out of the lungs

Trachea (windpipe)

Carries air from the mouth and nose to the lungs.


Two tubes which carry air to the lungs


Small tubes in the lung


Small air sacs found at the end of each bronchiole.


Bones which surround the lungs to form the ribcage.


A sheet of muscle found underneath the lungs.

Lung volume

Measure of the amount of air breathed in or out.

3.8.4 Digestion


Substances that speed up the chemical reactions of digestion.

Dietary fibre

Parts of plants that cannot be digested, which helps the body eliminate waste.


The body’s main source of energy. There are two types: simple (sugars) and complex (starch).

Lipids (fats and oils)

A source of energy. Found in butter, milk, eggs, nuts.


Nutrient your body uses to build new tissue for growth and repair. Sources are meat, fish, eggs, dairy products, beans, nuts and seeds.


A sac where food is mixed with acidic juices to start the digestion of protein and kill microorganisms

Small intestine

Upper part of the intestine where digestion is completed and nutrients are absorbed by the blood.

Large intestine

Lower part of the intestine from which water is absorbed and where faeces are formed.

Gut bacteria

Microorganisms that naturally live in the intestine and help food break down.

3.9 Eco systems

3.9.1 Interdependence

Food web

Shows how food chains in an ecosystem are linked.

Food chain

Part of a food web, starting with a producer, ending with a top predator.


The living things in a given area and their non-living environment.


The surrounding air, water and soil where an organism lives.


Group of the same species living in an area.


Green plant or algae that makes its own food using sunlight.


Animal that eats other animals or plants


Organism that breaks down dead plant and animal material so nutrients can be recycled back to the soil or water.

3.9.2 Plant Reproduction


Contains the plant male sex cells found on the stamens.


Female sex cells in plants found in the ovary


Transfer of pollen from the male part of the flower to the female part of the flower on the same or another plant.


Joining of a nucleus from a male and female sex cell.


Structure that contains the embryo of a new plant.


Structure that the ovary becomes after fertilisation, which contains seeds.


The female part of the flower, made up of the stigma where the pollen lands, style and ovary.

3.9.3 Respiration

Aerobic respiration

Breaking down glucose with oxygen to release energy and producing carbon dioxide and water.

Anaerobic respiration (fermentation)

Releasing energy from the breakdown of glucose without oxygen, producing lactic acid (in animals) and ethanol and carbon dioxide (in plants and microorganisms).

3.9.4 Photosynthesis


Chemicals containing minerals that plants need to build new tissues.


A process where plants and algae turn carbon dioxide and water into glucose and release oxygen.


Green pigment in plants and algae which absorbs light energy.


Pores in the bottom of a leaf which open and close to let gases in and out.

3.10 Genes

3.10.1 Variation


A group of living things that have more in common with each other than with other groups.


The differences within and between species

Continuous variation

Where differences between living things can have any numerical value.

Discontinuous variation

Where differences between living things can only be grouped into categories.

3.10.2 Human Reproduction


The male gamete (sex cell) in animals is a sperm, the female an egg.


Joining of a nucleus from a male and female sex cell.


Organ which contains eggs


Organ where sperm are produced

Oviduct, or fallopian tube

Carries an egg from the ovary to the uterus and is where fertilisation occurs.

Uterus, or womb

Where a baby develops in a pregnant woman.


Release of an egg cell during the menstrual cycle, which may be met by a sperm.


Loss of the lining of the uterus during the menstrual cycle.

Reproductive system

All the male and female organs involved in reproduction.


Organ which carries sperm out of the male’s body


Where the penis enters the female’s body and sperm is received.


The developing baby during pregnancy.


Process where the baby develops during pregnancy.


Organ that provides the foetus with oxygen and nutrients and removes waste substances.

Amniotic fluid

Liquid that surrounds and protects the foetus.

Umbilical cord

Connects the foetus to the placenta

3.10.3 Evolution


Group of organisms of the same kind living in the same place.

Natural selection

Process by which species change over time in response to environmental changes and competition for resources.


When no more individuals of a species remain


The variety of living things. It is measured as the differences between individuals of the same species, or the number of different species in an ecosystem.


When two or more living things struggle against each other to get the same resource.


Theory that the animal and plant species living today descended from species that existed in the past.

3.10.3 Inheritance

Inherited characteristics

Features that are passed from parents to their offspring.


A molecule found in the nucleus of cells that contains genetic information.


Thread-like structures containing tightly coiled DNA.


A section of DNA that determines an inherited characteristic.

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