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.
Anomalous
A piece of data that does not fit the pattern.
Mean
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
Observation
Information gathered by your senses.
Evidence
Information from an observation or experiment that supports an idea.
2.7 Critique Claims
Claim
A statement that says something is true.
Evidence
The facts, scientific ideas, data or conclusions that support the claim
Reasoning
Your ideas about what the evidence means, in the form of an argument for or against the claim.
2.7 Critique Claims
Claim
A statement that says something is true.
Evidence
The facts, scientific ideas, data or conclusions that support the claim
Reasoning
Your ideas about what the evidence means, in the form of an argument for or against the claim.
2.9 Collect Data
Range
The maximum and minimum values of a variable.
Interval
The gap between the values of the independent variable
Control group
Those that are not exposed to the factor being tested.
Repeatable
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.
Variable
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
Correlation
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
Hypothesis
An explanation you can test which includes a reason and a ‘science idea’.
Observation
Information gathered by your senses.
Prediction
What you think will happen in an experiment
2.13 Estimate Risks
Risk
How likely something is to be harmful
Hazard
A situation that presents a threat to people
Benefit
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
Bias
When an experimenter affects the outcome, or when a journalist favours a point of view
Funder
Organisation or person that pays for scientific research
Journal
Magazine which publishes science research for others to read.
3.1 Forces
3.1.1 Gravity
Weight
The force of gravity on an object (N)
Non-contact force
One that acts without direct contact.
Mass
The amount of stuff in an object (kg)
Gravitational field strength, g
The force from gravity on 1 kg (N/kg).
Field
The area where other objects feel a gravitational force.
3.1.2 Contact Forces
Equilibrium
State of an object when opposing forces are balanced.
Deformation
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.
Newton
Unit for measuring forces (N).
Resultant force
Single force which can replace all the forces acting on an object and have the same effect
Friction
Force opposing motion which is caused by the interaction of surfaces moving over one another. It is called ‘drag’ if one is a fluid.
Tension
Force extending or pulling apart.
Compression
Force squashing or pushing together.
Contact force
One that acts by direct contact
3.1.3 Pressure
Fluid
A substance with no fixed shape, a gas or a liquid.
Pressure
The ratio of force to surface area, in N/m2, and how it causes stresses in solids.
Upthrust
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
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.
Acceleration
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).
Resistance
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.
Electrons
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.
Current
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
Electromagnet
A non-permanent magnet turned on and off by controlling the current through it.
Solenoid
Wire wound into a tight coil, part of an electromagnet.
Core
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
Power
How quickly energy is transferred by a device (watts).
Energy resource
Something with stored energy that can be released in a useful way.
Non-renewable
An energy resource that cannot be replaced and will be used up.
Renewable
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.
Dissipated
Become spread out wastefully
3.3.3 Work
Work
The transfer of energy when a force moves an object, in joules.
Lever
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.
Displacement
The distance an object moves from its original position.
Deformation
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.
Temperature
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.
Conduction
Transfer of thermal energy by the vibration of particles.
Convection
Transfer of thermal energy when particles in a heated fluid rise.
Radiation
Transfer of thermal energy as a wave.
3.4 Waves
3.4.1 Sound
Vibration
A back and forth motion that repeats
Longitudinal wave
Where the direction of vibration is the same as that of the wave.
Volume
How loud or quiet a sound is, in decibels (dB).
Pitch
How low or high a sound is. A low (high) pitch sound has a low (high) frequency.
Amplitude
The maximum amount of vibration, measured from the middle position of the wave, in metres.
Wavelength
Distance between two corresponding points on a wave, in metres.
Frequency
The number of waves produced in one second, in hertz.
Vacuum
A space with no particles of matter in it.
Oscilloscope
Device for viewing patterns of sound waves that have been turned into electrical current.
Absorption
When energy is transferred from sound to a material.
Auditory range
The lowest and highest frequencies that a type of animal can hear.
Echo
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.
Refraction
Change in the direction of light going from one material into another.
Absorption
When energy is transferred from light to a material.
Scattering
When light bounces off an object in all directions.
Transparent
A material that allows all light to pass through it.
Translucent
A material that allows some light to pass through it.
Opaque
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.
Retina
Layer at the back of the eye with light detecting cells and where image is formed.
3.4.3 Wave Effects
Ultrasound
Sound waves with frequencies higher than the human auditory range.
Ultraviolet (UV)
Waves with frequencies higher than light, which human eyes cannot detect.
Microphone
Turns the pressure wave of sound hitting it into an electrical signal.
Loudspeaker
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
Waves
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.
Transmission
Where waves travel through a medium rather than be absorbed or reflected.
3.5 Matter
3.5.1 Particle Model
Particle
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.
Diffusion
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.
Density
How much matter there is in a particular volume, or how close the particles are.
Evaporate
Change from liquid to gas at the surface of a liquid, at any temperature.
Boil
Change from liquid to a gas of all the liquid when the temperature reaches boiling point.
Condense
Change of state from gas to liquid when the temperature drops to the boiling point.
Melt
Change from solid to liquid when the temperature rises to the melting point.
Freeze
Change from liquid to a solid when the temperature drops to the melting point.
Sublime
Change from a solid directly into a gas
3.5.2 Separating Mixtures
Solvent
A substance, normally a liquid, that dissolves another substance.
Solute
A substance that can dissolve in a liquid.
Dissolve
When a solute mixes completely with a solvent.
Solution
Mixture formed when a solvent dissolves a solute.
Soluble (insoluble)
Property of a substance that will (will not) dissolve in a liquid.
Solubility
Maximum mass of solute that dissolves in a certain volume of solvent.
Pure substance
Single type of material with nothing mixed in.
Mixture
Two or more pure substances mixed together, whose properties are different to the individual substances.
Filtration
Separating substances using a filter to produce a filtrate (solution) and residue.
Distillation
Separating substances by boiling and condensing liquids.
Evaporation
A way to separate a solid dissolved in a liquid by the liquid turning into a gas.
Chromatography
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.
Groups
Columns of the periodic table.
Periods
Rows of the periodic table.
3.5.4 Elements
Elements
What all substances are made up of, and which contain only one type of atom.
Atom
The smallest particle of an element that can exist.
Molecules
Two to thousands of atoms joined together. Most non-metals exist either as small or giant molecules.
Compound
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.
Polymer
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
Metals
Shiny, good conductors of electricity and heat, malleable and ductile, and usually solid at room temperature.
Non-metals
Dull, poor conductors of electricity and heat, brittle and usually solid or gaseous at room temperature.
Displacement
Reaction where a more reactive metal takes the place of a less reactive metal in a compound
Oxidation
Reaction in which a substance combines with oxygen.
Reactivity
The tendency of a substance to undergo a chemical reaction.
3.6.2 Acids and Alkalis
pH
Scale of acidity and alkalinity from 0 to 14.
Indicators
Substances used to identify whether unknown solutions are acidic or alkaline.
Base
A substance that neutralises an acid – those that dissolve in water are called alkalis.
Concentration
A measure of the number of particles in a given volume.
3.6.3 Chemical Energy
Catalysts
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
Fuel
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.
Reactants
Substances that react together, shown before the arrow in an equation.
Products
Substances formed in a chemical reaction, shown after the reaction arrow in an equation.
Conserved
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.
Weathering
The wearing down of rock by physical, chemical or biological processes.
Erosion
Movement of rock by water, ice or wind (transportation).
Minerals
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.
Strata
Layers of sedimentary rock.
3.7.2 Universe
Galaxy
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).
Stars
Bodies which give out light, and which may have a solar system of planets.
Orbit
Path taken by a satellite, planet or star moving around a larger body. Earth completes one orbit of the Sun every year.
Exoplanet
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.
Mineral
Naturally occurring metal or metal compound.
Ore
Naturally occurring rock containing sufficient minerals for extraction.
Extraction
Separation of a metal from a metal compound.
Recycling
Processing a material so that it can be used again.
Electrolysis
Using electricity to split up a compound into its elements.
3.8 Organisms
3.8.1 Movement
Joints
Places where bones meet
Bone marrow
Tissue found inside some bones where new blood cells are made.
Ligaments
Connect bones in joints
Tendons
Connect muscles to bones.
Cartilage
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
Cell
The unit of a living organism, contains parts to carry out life processes.
Uni-cellular
Living things made up of one cell
Multi-cellular
Living things made up of many types of cell.
Tissue
Group of cells of one type
Organ
Group of different tissues working together to carry out a job.
Diffusion
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.
Nucleus
Contains genetic material (DNA) which controls the cell’s activities.
Vacuole
Area in a cell that contains liquid, and can be used by plants to keep the cell rigid and store substances.
Mitochondria
Part of the cell where energy is released from food molecules.
Cell wall
Strengthens the cell. In plant cells it is made of cellulose.
Chloroplast
Absorbs light energy so the plant can make food.
Cytoplasm
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
Breathing
The movement of air in and out of the lungs
Trachea (windpipe)
Carries air from the mouth and nose to the lungs.
Bronchi
Two tubes which carry air to the lungs
Bronchioles
Small tubes in the lung
Alveoli
Small air sacs found at the end of each bronchiole.
Ribs
Bones which surround the lungs to form the ribcage.
Diaphragm
A sheet of muscle found underneath the lungs.
Lung volume
Measure of the amount of air breathed in or out.
3.8.4 Digestion
Enzymes
Substances that speed up the chemical reactions of digestion.
Dietary fibre
Parts of plants that cannot be digested, which helps the body eliminate waste.
Carbohydrates
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.
Protein
Nutrient your body uses to build new tissue for growth and repair. Sources are meat, fish, eggs, dairy products, beans, nuts and seeds.
Stomach
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.
Ecosystem
The living things in a given area and their non-living environment.
Environment
The surrounding air, water and soil where an organism lives.
Population
Group of the same species living in an area.
Producer
Green plant or algae that makes its own food using sunlight.
Consumer
Animal that eats other animals or plants
Decomposer
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
Pollen
Contains the plant male sex cells found on the stamens.
Ovules
Female sex cells in plants found in the ovary
Pollination
Transfer of pollen from the male part of the flower to the female part of the flower on the same or another plant.
Fertilisation
Joining of a nucleus from a male and female sex cell.
Seed
Structure that contains the embryo of a new plant.
Fruit
Structure that the ovary becomes after fertilisation, which contains seeds.
Carpel
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
Fertilisers
Chemicals containing minerals that plants need to build new tissues.
Photosynthesis
A process where plants and algae turn carbon dioxide and water into glucose and release oxygen.
Chlorophyll
Green pigment in plants and algae which absorbs light energy.
Stomata
Pores in the bottom of a leaf which open and close to let gases in and out.
3.10 Genes
3.10.1 Variation
Species
A group of living things that have more in common with each other than with other groups.
Variation
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
Gamete
The male gamete (sex cell) in animals is a sperm, the female an egg.
Fertilisation
Joining of a nucleus from a male and female sex cell.
Ovary
Organ which contains eggs
Testicle
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.
Ovulation
Release of an egg cell during the menstrual cycle, which may be met by a sperm.
Menstruation
Loss of the lining of the uterus during the menstrual cycle.
Reproductive system
All the male and female organs involved in reproduction.
Penis
Organ which carries sperm out of the male’s body
Vagina
Where the penis enters the female’s body and sperm is received.
Foetus
The developing baby during pregnancy.
Gestation
Process where the baby develops during pregnancy.
Placenta
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
Population
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.
Extinct
When no more individuals of a species remain
Biodiversity
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.
Competition
When two or more living things struggle against each other to get the same resource.
Evolution
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.
DNA
A molecule found in the nucleus of cells that contains genetic information.
Chromosomes
Thread-like structures containing tightly coiled DNA.
Gene
A section of DNA that determines an inherited characteristic.
