Use these 200 MYP science words and terms to describe observations, explain processes, interpret data and evaluate claims. Every entry has a short meaning and an original example. This is an eduKate teaching selection for biology, chemistry, physics and inquiry, not an IB-issued vocabulary list.
The 200-word list: meanings and learning examples
1–20: Questions, models and measurement · 21–40: Investigation, data and reasoning · 41–60: Particles, substances and changes of state · 61–80: Chemical reactions and their explanations · 81–100: Forces, motion and mathematical descriptions · 101–120: Energy, heating and resources · 121–140: Electricity, magnetism and waves · 141–160: Cells, body systems and life processes · 161–180: Plants, inheritance and evolution · 181–200: Ecology, environmental systems and decisions
Assessment requirements · Starting check · Fencing Method · Practice and answers
1–20. Questions, models and measurement
- scientific question — A question about the natural world that can be investigated using evidence. Example: Our scientific question asks how wrapping affects the cooling of water.
- hypothesis — A proposed explanation that can be tested against evidence. Example: Our hypothesis is that trapped air in the wrapping reduces energy transfer.
- prediction — A stated result expected under particular conditions. Example: Our prediction is that the wrapped cup will have a higher final temperature.
- observation — Information obtained through the senses or measuring equipment. Example: The colour change was an observation; its cause needed further investigation.
- inference — An interpretation drawn from observations and existing knowledge. Example: Our inference about the hidden magnet explains the movement of the compass.
- evidence — Information used to support or challenge a claim. Example: The repeated temperature readings provide evidence for our comparison.
- model — A representation used to describe, explain or predict aspects of a system. Example: The particle model helps explain why a gas can be compressed.
- system — The objects or region chosen as the focus of a scientific study. Example: We defined the system as the water and its container.
- surroundings — Everything outside the system being studied. Example: Energy passed from the warmer water to its cooler surroundings.
- measurement — A process of finding a quantity's value by comparison with a unit. Example: The measurement of water volume was recorded in millilitres.
- unit — An agreed quantity used as a reference for measurements of the same kind. Example: The kilogram is the SI unit of mass.
- mass — A measure of an object's inertia, recorded in kilograms in SI. Example: The mass of the sample was 0.25 kg.
- volume — The amount of three-dimensional space occupied by an object or substance. Example: The volume of the cube was 8 cm³.
- density — Mass per unit volume of a substance or object. Example: The sample's density was 3 g/cm³ because 15 cm³ had a mass of 45 g.
- temperature — A measure of hotness that determines the direction of spontaneous heat transfer. Example: The water's temperature fell as energy transferred to the cooler room.
- accuracy — How closely a measurement agrees with the quantity's true or accepted reference value. Example: We checked accuracy by comparing the thermometer with a suitable reference.
- precision — How closely repeated measurements agree under stated conditions. Example: The closely grouped readings showed good precision in this trial set.
- uncertainty — A quantified indication of doubt about a measurement result. Example: We reported measurement uncertainty alongside the measured length.
- resolution — The smallest change in a quantity that an instrument can distinguish. Example: The digital balance had a resolution of 0.1 g.
- calibration — Establishing how an instrument's readings relate to reference values. Example: Calibration revealed that the thermometer read higher than the reference.
21–40. Investigation, data and reasoning
- independent variable — The factor deliberately changed in an investigation. Example: The independent variable was the material wrapped around the cup.
- dependent variable — The outcome measured to investigate the effect of a change. Example: The dependent variable was the water temperature after five minutes.
- controlled variable — A factor kept the same to make a comparison more meaningful. Example: The starting water volume was a controlled variable.
- control group — A comparison group without the treatment being investigated. Example: The unwrapped cups formed the control group for the wrapping investigation.
- trial — One run of an investigation or test. Example: Each trial began with fresh water at the same starting temperature.
- repeatability — Agreement between results obtained under the same specified measurement conditions. Example: Repeating the procedure with the same equipment helped us assess repeatability.
- reproducibility — Agreement between results when specified measurement conditions are changed. Example: A second laboratory used different equipment to investigate reproducibility.
- sample — A selected part of a larger group or material that is studied. Example: Our sample contained twenty leaves from several plants.
- mean — The sum of numerical values divided by the number of values. Example: The mean of 35, 36 and 37 °C is 36 °C.
- range — The largest numerical value minus the smallest in a data set. Example: The range of 35, 36 and 37 °C is 2 °C.
- anomaly — A result or pattern that differs unexpectedly from the others. Example: We investigated the anomaly before deciding how to report it.
- table — An organised arrangement of information in rows and columns. Example: The table included a heading and unit for each measurement column.
- graph — A visual display of relationships or patterns in data. Example: Our graph compared mean final temperature for three wrapping choices.
- axis — A reference line used to position values on a graph. Example: The vertical axis showed temperature in degrees Celsius.
- gradient — The change in the vertical quantity divided by the change in the horizontal quantity. Example: The gradient of the distance–time graph represented speed along that section.
- correlation — An association in which two variables vary together. Example: The correlation between shade and plant size did not establish a cause.
- causation — A relationship in which a change in one factor produces a change in another. Example: The observational survey alone could not establish causation.
- conclusion — A judgement that answers a question using the available evidence. Example: Our conclusion applied to the tested materials and conditions.
- limitation — A feature that restricts the strength or scope of an investigation. Example: Testing only one thickness was a limitation of our comparison.
- evaluation — A reasoned assessment of evidence, methods, conclusions or implications. Example: Our evaluation connected each proposed improvement to a specific weakness.
41–60. Particles, substances and changes of state
- atom — The smallest unit retaining an element's identity, with a nucleus and electrons. Example: A neutral carbon atom has six protons and six electrons.
- element — A substance whose atoms all have the same number of protons. Example: Oxygen is an element even when its atoms form O₂ molecules.
- compound — A substance containing atoms of different elements chemically combined in fixed proportions. Example: Water is a compound containing hydrogen and oxygen.
- mixture — Two or more substances together without being chemically combined into one substance. Example: Air is a mixture of several gases.
- molecule — A discrete, electrically neutral group of two or more bonded atoms. Example: An oxygen molecule contains two oxygen atoms.
- ion — An atom or group of atoms with a net electric charge. Example: A sodium ion has a positive charge after losing an electron.
- proton — A positively charged particle found in an atomic nucleus. Example: Each proton contributes to the positive charge of the nucleus.
- neutron — An electrically neutral particle found in atomic nuclei. Example: A neutron adds mass without adding electric charge.
- electron — A negatively charged particle found outside an atom's nucleus. Example: A transferred electron can change an atom into an ion.
- atomic number — The number of protons in an atom's nucleus. Example: The atomic number of carbon is six.
- solid — A state of matter with a fixed shape and volume under ordinary conditions. Example: The solid kept its shape when moved to another container.
- liquid — A state of matter with a fixed volume but a shape that fits its container. Example: The liquid spread across the bottom of the beaker.
- gas — A state of matter that expands to fill its container. Example: The gas occupied the available space inside the sealed syringe.
- melting — A change of state from solid to liquid. Example: Melting changed the ice into liquid water.
- freezing — A change of state from liquid to solid. Example: Freezing changed the liquid water into ice.
- evaporation — A change from liquid to gas at a liquid's surface. Example: Evaporation occurred at the puddle's surface below the boiling point.
- boiling — Vaporisation throughout a liquid when its vapour pressure matches the surrounding pressure. Example: Boiling produced bubbles of water vapour throughout the water.
- condensation — A change of state from gas to liquid. Example: Condensation formed liquid droplets on the cold window.
- solution — A uniform mixture in which one or more substances are dissolved in another. Example: The salt solution looked clear although dissolved salt remained present.
- solubility — The maximum amount of a substance that dissolves in a stated amount of solvent under specified conditions. Example: We compared solubility at the same temperature and solvent volume.
61–80. Chemical reactions and their explanations
- reactant — A starting substance consumed in a chemical reaction. Example: Magnesium was a reactant in the formation of magnesium oxide.
- product — A substance formed by a chemical reaction. Example: Magnesium oxide was the product of the reaction.
- chemical reaction — A process in which starting substances become different substances. Example: The chemical reaction formed a gas and a new dissolved substance.
- physical change — A change that does not create a different chemical substance. Example: Melting ice is a physical change because the substance remains water.
- conservation of mass — The principle that total mass remains unchanged during a chemical reaction in a closed system. Example: Our sealed-container results were consistent with conservation of mass.
- chemical bond — An interaction that holds atoms or ions together in a chemical structure. Example: Breaking a chemical bond requires energy.
- covalent bond — A bond in which atoms share electron pairs. Example: The hydrogen atoms share electrons in a covalent bond.
- ionic bond — The electrostatic attraction between oppositely charged ions. Example: An ionic bond holds neighbouring sodium and chloride ions together.
- oxidation — A process involving loss of electrons by a chemical species. Example: Magnesium undergoes oxidation when its atoms lose electrons.
- combustion — A reaction with an oxidant, commonly oxygen, that releases energy and often produces a flame. Example: Complete combustion of methane in oxygen produces carbon dioxide and water.
- catalyst — A substance that increases reaction rate without being used up overall. Example: The catalyst provided an alternative reaction pathway.
- reaction rate — The change in the amount or concentration of a reactant or product per unit time. Example: We compared reaction rate using the volume of gas collected each minute.
- acid — A substance that can donate protons, producing hydronium ions when dissolved in water. Example: The acid produced a solution with a pH below seven at 25 °C.
- base — A substance that can accept protons. Example: The base reacted with hydrogen ions from the acid.
- alkali — A base that dissolves in water to produce hydroxide ions. Example: Sodium hydroxide forms an alkali when dissolved in water.
- pH — A logarithmic measure used to express how acidic or alkaline an aqueous solution is. Example: A change in pH from four to three indicates greater acidity.
- neutralisation — A reaction between an acid and a base. Example: Neutralisation can leave excess acid if too little base is added.
- salt — An ionic compound made of positive and negative ions. Example: Sodium chloride is a salt containing sodium ions and chloride ions.
- exothermic — Describing a process that transfers energy as heat to its surroundings. Example: The exothermic reaction warmed the surrounding solution.
- endothermic — Describing a process that takes in energy as heat from its surroundings. Example: The endothermic process cooled the surrounding solution.
81–100. Forces, motion and mathematical descriptions
- force — A push or pull arising from an interaction that can affect motion or shape. Example: The force stretched the spring.
- weight — The gravitational force acting on an object. Example: The object's weight was measured in newtons.
- gravity — The attractive interaction between objects with mass. Example: Earth's gravity pulls the falling ball downwards.
- friction — A contact force opposing relative sliding or its tendency between surfaces. Example: Friction between the shoes and ground helped the runner accelerate.
- drag — A resistive force caused by motion through a fluid. Example: Air drag increased as the cyclist moved faster.
- upthrust — The upward force exerted by a fluid on an immersed object. Example: The floating block's upthrust balanced its weight.
- resultant force — The single force equivalent to the combined effect of all forces on an object. Example: A non-zero resultant force changed the trolley's velocity.
- equilibrium — A state in which forces and turning effects are balanced. Example: The stationary beam was in equilibrium.
- inertia — The tendency of an object to resist a change in its velocity. Example: The heavier trolley had greater inertia.
- distance — The total length of a path travelled. Example: The walker covered a distance of ten metres before returning.
- displacement — The change in position from start to finish, including direction. Example: A complete lap ends with zero displacement.
- speed — The rate at which distance is travelled. Example: The average speed was distance divided by elapsed time.
- velocity — The rate of change of displacement, including direction. Example: The car's velocity changed when it turned at constant speed.
- acceleration — The rate of change of velocity. Example: Braking produced an acceleration opposite to the car's motion.
- momentum — The product of an object's mass and velocity. Example: The moving trolley's momentum increased when its speed doubled.
- pressure — Normal force per unit area. Example: The same force produced greater pressure over a smaller area.
- elasticity — The ability to return to an original shape after a deforming force is removed. Example: The spring showed elasticity within its working range.
- extension — The increase in length from an object's original length. Example: The spring's extension was 3 cm beyond its original length.
- proportional — Describing quantities linked by a constant ratio in direct proportion. Example: Within the spring's proportional range, doubling the force doubled its extension.
- vector — A quantity with both magnitude and direction. Example: Velocity is a vector because direction matters.
101–120. Energy, heating and resources
- energy — A quantity transferred or transformed during changes, conserved overall. Example: The moving ball transferred energy when it struck the target.
- work — Energy transferred by the component of a force acting along an object's displacement. Example: The upward force did work as the box rose.
- power — The rate of transferring energy or doing work. Example: The motor's power was 50 W when it transferred 100 J in two seconds.
- kinetic energy — Energy associated with an object's motion. Example: The trolley's kinetic energy increased as its speed increased, with its mass unchanged.
- gravitational potential energy — Energy associated with position in a gravitational field. Example: Raising the book increased its gravitational potential energy relative to the floor.
- elastic potential energy — Energy stored through elastic deformation. Example: The stretched spring stored elastic potential energy.
- chemical energy — Energy associated with the chemical arrangement of a system. Example: A battery transfers chemical energy through reactions in its cells.
- internal energy — The total microscopic kinetic and potential energy within a system. Example: Heating can increase a substance's internal energy.
- heat — Energy transferred because of a temperature difference. Example: Heat transferred from the warmer water to the cooler surroundings.
- conduction — Energy transfer through microscopic interactions without bulk movement of the material. Example: Conduction transferred energy along the metal rod.
- convection — Energy transfer associated with bulk movement of a fluid. Example: Convection carried energy as warmer water rose in the container.
- radiation — Energy transfer by electromagnetic waves. Example: Solar radiation can travel through the vacuum of space.
- thermal insulator — A material that slows energy transfer by conduction. Example: Trapped air can act as a thermal insulator.
- thermal conductor — A material that transfers energy readily by conduction. Example: Copper is a thermal conductor used in many heat exchangers.
- specific heat capacity — Energy needed per unit mass for a one-degree temperature rise without a change of state. Example: Water's high specific heat capacity helps it resist rapid temperature change.
- latent heat — Energy transferred during a change of state without a temperature change under fixed conditions. Example: The latent heat supplied during melting did not raise the pure ice–water mixture's temperature.
- efficiency — Useful output energy or power divided by total input energy or power. Example: The device's efficiency was 0.80 because 80 J of each 100 J input became useful output.
- renewable — Describing an energy resource replenished naturally on a human timescale. Example: Wind is a renewable energy resource.
- non-renewable — Describing an energy resource used faster than it is naturally replenished. Example: Coal is a non-renewable resource formed over geological timescales.
- conservation of energy — The principle that total energy remains constant in an isolated system. Example: Our explanation used conservation of energy to account for several energy transfers.
121–140. Electricity, magnetism and waves
- electric charge — A property of matter responsible for electric interactions, measured in coulombs. Example: The plastic rod gained a net electric charge when electrons transferred to it.
- current — The rate of flow of electric charge. Example: The current was 2 A when 2 C of charge passed each second.
- potential difference — Energy transferred per unit charge between two points. Example: A potential difference of 6 V corresponds to 6 J transferred per coulomb.
- resistance — Potential difference divided by current for a component under stated conditions. Example: The component's resistance was 3 Ω at 6 V and 2 A.
- circuit — A connected arrangement of electrical components, with a complete path needed for steady current. Example: Closing the switch completed the circuit.
- series circuit — A circuit with components connected along one path for current. Example: The same current flowed through both lamps in the series circuit.
- parallel circuit — A circuit with branches connected between shared junctions. Example: Each branch of the parallel circuit had the same potential difference across it.
- electrical conductor — A material containing charges that can move readily through it. Example: Copper is an electrical conductor used inside many wires.
- electrical insulator — A material in which electric charge does not move readily under ordinary conditions. Example: The plastic coating acts as an electrical insulator around the wire.
- magnetic field — A region in which magnetic forces can act on suitable materials or moving charges. Example: The compass needle aligned with the local magnetic field.
- electromagnet — A magnet produced by electric current, often using a coil around an iron core. Example: The electromagnet attracted the iron object while current flowed.
- induction — In electromagnetism, production of an electromotive force when magnetic flux linkage changes. Example: Moving the magnet relative to the coil produced induction.
- wave — A disturbance that transfers energy without net transport of the medium with the wave. Example: The wave carried energy along the rope while each section oscillated.
- wavelength — The distance between adjacent points in a wave that are in the same phase. Example: We measured wavelength from one crest to the next crest.
- frequency — The number of complete cycles occurring each second. Example: A frequency of 50 Hz means fifty cycles each second.
- amplitude — The maximum displacement from an equilibrium position in an oscillation. Example: A larger amplitude meant that the vibrating point moved farther from equilibrium.
- period — The time taken for one complete cycle. Example: The wave's period was 0.02 s when its frequency was 50 Hz.
- reflection — A wave's change of direction back into its original medium at a boundary. Example: Reflection produced an echo from the wall.
- refraction — A change in a wave's speed when entering a different medium, often changing its direction. Example: Refraction bent the light ray as it entered the glass at an angle.
- electromagnetic spectrum — The full range of electromagnetic waves ordered by frequency or wavelength. Example: Visible light occupies a small part of the electromagnetic spectrum.
141–160. Cells, body systems and life processes
- cell — The basic structural and functional unit of living organisms. Example: The microscope image showed the boundary of each cell.
- cell membrane — A selectively permeable boundary controlling movement into and out of a cell. Example: The cell membrane helped regulate substances entering the cell.
- cytoplasm — The contents inside a cell membrane excluding the nucleus where present. Example: Many metabolic reactions occur within the cytoplasm.
- nucleus — In a eukaryotic cell, a membrane-bound compartment containing most of its DNA. Example: The plant cell's nucleus contained chromosomes.
- mitochondrion — An organelle where major stages of aerobic respiration occur in eukaryotic cells. Example: The mitochondrion contributed to ATP production in the muscle cell.
- ribosome — A cellular structure that assembles proteins using genetic instructions. Example: The ribosome joined amino acids to build a protein.
- tissue — A group of cells organised to carry out related functions. Example: Muscle tissue contracts to produce movement.
- organ — A body structure made of different tissues working together for particular functions. Example: The heart is an organ that pumps blood.
- organ system — A group of organs working together in major body functions. Example: The digestive organ system breaks down food and absorbs nutrients.
- enzyme — A biological catalyst, usually a protein. Example: The enzyme increased reaction rate without being consumed overall.
- substrate — A substance on which an enzyme acts. Example: The substrate fitted the enzyme's active site.
- diffusion — The net movement of particles down a concentration gradient because of random motion. Example: Diffusion moved oxygen into the cell where its concentration was lower.
- osmosis — The net movement of water through a selectively permeable membrane from higher to lower water potential. Example: Osmosis changed the mass of the plant tissue in the solution.
- active transport — Movement of substances across a membrane using cellular energy, often against a concentration gradient. Example: Active transport helped the root cell take up mineral ions.
- respiration — Cellular reactions that transfer energy from substances such as glucose to usable forms including ATP. Example: Plant cells carry out respiration as well as photosynthesis.
- aerobic — Describing a process that requires oxygen. Example: Aerobic respiration uses oxygen in the breakdown of glucose.
- anaerobic — Describing a process occurring without oxygen. Example: Yeast can obtain energy through anaerobic breakdown of sugars.
- digestion — The breakdown of food into smaller components that can be absorbed. Example: Digestion converted large starch molecules into smaller soluble sugars.
- absorption — The movement of substances into a tissue or system. Example: Absorption transferred digested nutrients across the small intestine's wall.
- homeostasis — Regulation that keeps internal conditions within suitable limits. Example: Homeostasis helped maintain body temperature within a narrow range.
161–180. Plants, inheritance and evolution
- photosynthesis — The process by which plants and some other organisms use light energy to make organic substances. Example: Photosynthesis in the leaf used carbon dioxide and water to produce sugars.
- chloroplast — An organelle in plants and algae where photosynthesis occurs. Example: Each chloroplast contained membranes involved in capturing light energy.
- chlorophyll — A green pigment that absorbs light for photosynthesis. Example: Chlorophyll absorbed light used in photosynthesis.
- stomata — Small adjustable pores, usually in leaves, through which gases and water vapour move. Example: The stomata allowed carbon dioxide to enter the leaf.
- transpiration — The loss of water vapour from a plant, mainly through stomata. Example: Transpiration contributed to water movement through the plant.
- xylem — Plant vascular tissue that transports water and mineral ions and provides support. Example: Water moved upwards through the xylem.
- phloem — Plant vascular tissue that transports dissolved sugars and other organic substances. Example: The phloem carried sugars from a source leaf towards a growing root.
- pollination — Transfer of pollen from an anther to a stigma in flowering plants. Example: A bee's movement helped pollination by transferring pollen between flowers.
- fertilisation — The fusion of gametes or their nuclei to form a zygote. Example: Fertilisation occurred after a male gamete reached the egg cell.
- germination — The beginning of growth from a seed when suitable conditions are available. Example: Germination began after the seed absorbed water.
- DNA — The molecule carrying genetic information in cells. Example: The sequence of bases in DNA stores genetic information.
- gene — A DNA sequence carrying instructions for a functional product such as RNA or a protein. Example: A gene contributed instructions used in producing an enzyme.
- chromosome — An organised structure of DNA, associated with proteins, carrying genetic information. Example: The chromosome contained many genes.
- allele — An alternative version of a gene at a particular position. Example: The plant inherited one allele from each parent at that gene position.
- inheritance — The passing of genetic information from parents to offspring. Example: Inheritance helped explain similarities between parents and offspring.
- variation — Differences among individuals, arising from genetic and environmental influences. Example: Leaf size showed variation within the population.
- mutation — A change in a DNA sequence. Example: A mutation can create a new allele.
- natural selection — A process in which heritable differences affect reproductive success and change populations across generations. Example: Natural selection increased the frequency of the useful inherited trait in that environment.
- adaptation — An inherited feature that improves survival or reproduction in a particular environment. Example: The thick insulating coat was an adaptation to cold conditions.
- evolution — Change in inherited characteristics of populations across generations. Example: Evolution describes population change, rather than an individual choosing a new trait.
181–200. Ecology, environmental systems and decisions
- organism — An individual living thing. Example: Each organism interacted with living and non-living parts of its habitat.
- population — Organisms of the same species living in a defined area at a given time. Example: The pond supported a population of one frog species.
- community — The populations of different species living in a defined area. Example: The pond community included plants, animals and microorganisms.
- ecosystem — A community and its non-living environment interacting as a system. Example: The pond ecosystem included water, organisms and their interactions.
- habitat — The place and environmental conditions in which an organism lives. Example: The shaded stream provided a suitable habitat for the insect larvae.
- niche — A species' ecological role and its use of environmental resources and conditions. Example: The bird's niche included feeding on insects in tree bark.
- biotic — Describing living components or influences in an ecosystem. Example: Competition from other plants was a biotic influence.
- abiotic — Describing non-living physical or chemical components of an environment. Example: Water temperature was an abiotic factor in the pond.
- producer — An organism that makes organic substances from inorganic sources using light or chemical energy. Example: The green alga was a producer in the pond food web.
- consumer — An organism obtaining energy by feeding on other organisms or their organic material. Example: The caterpillar was a consumer that ate leaves.
- decomposer — An organism that breaks down dead organic matter and returns nutrients to the environment. Example: The fungus acted as a decomposer on the fallen branch.
- food chain — A sequence showing feeding relationships and the direction of energy transfer. Example: The food chain ran from grass to grasshopper to bird.
- food web — A network of connected feeding relationships in an ecosystem. Example: The food web showed that the bird had several food sources.
- competition — An interaction in which organisms use the same limited resource. Example: Competition for light affected plant growth.
- predation — An interaction in which one organism captures and eats another. Example: The spider catching the fly was an example of predation.
- biodiversity — The variety of life, including genetic, species and ecosystem diversity. Example: Our survey measured one aspect of biodiversity: the variety of plant species.
- carbon cycle — The movement of carbon among living things, air, water and other Earth stores. Example: Photosynthesis transfers carbon from the atmosphere into organisms within the carbon cycle.
- greenhouse effect — Warming associated with atmospheric gases absorbing and emitting infrared radiation. Example: The natural greenhouse effect helps keep Earth's surface warmer than it would otherwise be.
- climate change — Long-term change in climate patterns and their statistical properties. Example: One unusually hot day is insufficient evidence by itself for climate change.
- sustainability — Maintaining environmental and human systems over time while considering resource use and consequences. Example: Our sustainability judgement considered material use, durability and disposal.
List check: 200 distinct entries in 10 groups of 20. This is a reference bank for learning and application, not a quota for one response.
The bank is a reference for different units and levels of confidence. Start with five words needed for your current task, then use the worked investigation, short practice and repair guide below. Accurate scientific meaning matters more than the number of technical terms in a paragraph.
Choose your next useful step
Choose the part of the guide that helps with your current task.
Guide contents
Sections 1–4: Understand the stage and use words accurately
Sections 5–6: Worked examples and practice
Sections 7–11: Review, revise and continue
The IB Middle Years Programme serves learners aged 11–16. Schools organise science through separate subjects, integrated courses or combinations. Follow your school’s unit sequence: a vocabulary term appearing here does not make it compulsory in every MYP year. The IB sciences overview explains the subject group’s inquiry focus.
| Criterion | Useful action in a response | Example language from this bank |
|---|---|---|
| A: Knowing and understanding | Explain a scientific idea and apply it to the problem. | density, diffusion, resultant force |
| B: Inquiring and designing | Frame a question and plan a defensible investigation. | hypothesis, independent variable, controlled variable |
| C: Processing and evaluating | Process results, interpret them and assess the method. | mean, anomaly, conclusion, limitation |
| D: Reflecting on the impacts of science | Consider consequences of scientific applications and document sources. | evidence, sustainability, evaluation |
The four criteria are equally weighted in the IB sciences subject brief. The table translates their purpose into practice; it is not a marking rubric. Use the task-specific instructions and descriptors supplied by your teacher.
Classroom tasks are set and assessed by schools. The MYP Year 5 personal project is mandatory and externally moderated. At the end of the programme, subject eAssessment is optional; on-screen science examinations are available in biology, chemistry, physics and integrated sciences. Check your school’s registration and current guidance before treating any examination route as your own. See the IB pages on assessment and on-screen examinations.
For an explanation, choose terms that establish a mechanism. For a calculation, define quantities, show substitution and give a sensible unit. For an evaluation or extended response, connect a claim to evidence and a limitation. Vocabulary cannot replace the scientific reasoning each task requires.
Start here: a short investigation check
Task: A class compares an unwrapped cup with a felt-wrapped cup. Each contains 80 mL of water initially at 40 °C. The cups have the same shape, stand in the same room and are measured after five minutes. Three independent trials give final temperatures of 30, 31 and 32 °C for the unwrapped cup, and 35, 35 and 35 °C for the felt-wrapped cup. These are invented practice data. Write six short sentences using independent variable, dependent variable, mean, precision, accuracy and conclusion. Identify what changed and what was measured. Calculate both averages, compare agreement within each set and decide whether these results establish the thermometer’s agreement with a reference value. Finish with a claim limited to the conditions tested. Do not add a calibration result that the task has not supplied. You may organise your working in a labelled table before writing.
Check your response and choose a route
The independent variable is the wrapping condition; the dependent variable is final water temperature after five minutes. The means are 31 °C and 35 °C. The recorded wrapped-cup values show closer agreement, although identical displayed values do not establish zero measurement uncertainty. Accuracy cannot be established without suitable reference information. A supported conclusion is that the felt-wrapped cup had a higher mean final temperature under these conditions.
- Foundations: If the quantity or unit is unclear, practise groups 1–2 with labelled tables and spoken sentences. Use three to five terms in one short explanation.
- Developing independence: If calculations are secure, combine a result with a scientific mechanism. Check whether the evidence supports the scope of your conclusion.
- Later MYP or extension: Compare alternative explanations, measurement limitations and further tests. Select additional terms from your current science unit, rather than trying to cover all ten groups at once.
These routes describe support needs, not official MYP year placements. A learner who understands the science in another language can first explain the idea in that language, then match the key English term to a diagram, quantity or process. Check the concept before judging the fluency of the sentence.
A useful word record contains four things: the term, its meaning in this context, the phrase it fits and one boundary on its use. For example: density; mass per volume; density of the sample; not simply how heavy the object is. This final boundary prevents a memorised definition from becoming a misleading explanation.
| Pattern | Useful wording | Check |
|---|---|---|
| Observation → inference | We observed a temperature fall; we inferred energy transfer to the surroundings. | Separate the recorded event from its interpretation. |
| Fell to → fell by | The temperature fell to 36 °C, a fall of 14 °C from 50 °C. | Final value and change are different quantities. |
| Mass → weight | The mass is 2 kg; weight is a gravitational force measured in newtons. | Do not replace one quantity with the other. |
| Association → cause | The variables were correlated; the survey did not establish causation. | A possible explanation still needs appropriate evidence. |
| Heat → temperature | Heat transferred to the cooler surroundings as the water’s temperature fell. | A body has internal energy; heat names a transfer. |
Write quantity and unit together, such as 15 cm³ or 6 V. Use a space between the numerical value and its unit symbol, including 25 °C. Unit symbols have fixed forms: kg is not written as kgs. The NIST guidance on expressing SI values explains these conventions. Define unfamiliar symbols near the equation where you use them.
Accuracy and precision are separate judgements. Closely grouped results may all be shifted from a reference value. Repetition can reveal variation, but cannot by itself remove a systematic instrument error. The distinction follows NIST measurement terminology. In your own evaluation, name the actual evidence available instead of describing every method as simply “accurate and reliable”.
The eduKate Fencing Method develops a correct core sentence by adding one useful layer at a time. Each addition must preserve the meaning and make the reasoning easier to follow. It is a teaching routine, not an IB assessment formula or a required paragraph template.
The numerical example here uses the full cooling investigation below: every cup starts at 50 °C, and the mean final temperatures are 42 °C for felt wrapping and 36 °C without wrapping.
- Set a correct core: “The felt-wrapped cup finished warmer.” The statement identifies an observable comparison.
- Add a measured detail: “After five minutes, the felt-wrapped cup had a mean final temperature of 42 °C, compared with 36 °C for the unwrapped cup.” Each value now has a quantity, time and unit.
- Add a justified explanation: “The smaller temperature fall is consistent with reduced energy transfer through the wrapping under these conditions.” The phrase consistent with distinguishes an explanation from a directly observed mechanism.
- Check and repair: Remove claims that the material “creates heat”, stops every transfer pathway or will outperform every other insulator. Ask what the data actually show.
- Transfer independently: Hide the model and explain a different data set. Keep the reasoning structure, but choose words and evidence that fit the new question.
A longer sentence is not automatically better. Split the result and its explanation when combining them makes the claim difficult to follow. For example: “The mean final temperature was 42 °C. This was 6 °C higher than the unwrapped cup.” That clear comparison can precede a separate sentence about the physical process.
Before adding another technical term, ask: does it identify the variable, describe the mechanism, interpret evidence or limit the conclusion? If it does none of those jobs, leave it out. The aim is independent scientific communication, including concise answers where the question calls for them.
The complete task and data
Invented classroom data: A class compares identical cups with no wrapping, paper wrapping or felt wrapping. Every trial uses 80 mL of fresh water starting at 50 °C, in a room at 22 °C. Paper and felt cover the same area to a measured thickness of 4 mm. Cups stand on the same surface, with no lids. The final temperature is recorded after five minutes using the same thermometer and method. There are three independent trials per condition. No reference calibration result is supplied.
| Wrapping | Trial 1 / °C | Trial 2 / °C | Trial 3 / °C |
|---|---|---|---|
| None | 36 | 35 | 37 |
| Paper | 39 | 38 | 40 |
| Felt | 42 | 41 | 43 |
Your brief: Identify the independent and dependent variables and two controlled variables. Calculate the mean final temperature, range and mean temperature fall for each condition. Choose a suitable graph for the comparison. Write a conclusion supported by numbers, explain one plausible mechanism and evaluate one limitation. Decide whether the repeated readings establish accuracy. This is a data exercise; carrying out a heating experiment is not required.
Process the numbers
For the unwrapped cup, mean final temperature = (36 + 35 + 37) ÷ 3 = 36 °C. Range = 37 − 35 = 2 °C. Mean temperature fall = 50 − 36 = 14 °C. Apply the same operations to the other conditions.
| Wrapping | Mean final temperature / °C | Range / °C | Mean temperature fall / °C |
|---|---|---|---|
| None | 36 | 2 | 14 |
| Paper | 39 | 2 | 11 |
| Felt | 42 | 2 | 8 |
The independent variable is wrapping condition. The dependent variable is water temperature after five minutes. Starting temperature and water volume are controlled variables; cup shape and elapsed time are further examples. A bar graph suits these three categories. Label the horizontal axis with wrapping condition and the vertical axis with mean final water temperature in °C. A line joining the categories would suggest an ordered continuous scale that the materials do not provide.
A model explanation with a defensible limit
“Under the tested conditions, felt wrapping reduced the water’s cooling most among the three conditions. Its mean temperature fall was 8 °C, compared with 11 °C for paper and 14 °C without wrapping. This pattern is consistent with the felt and trapped air reducing energy transfer through the cup’s sides. However, the data do not isolate every transfer pathway, and only one wrapping thickness was tested. The result therefore supports this comparison, not a claim that felt is always the best insulation.”
The smaller fall is the finding. The proposed physical mechanism is an interpretation supported by scientific knowledge; the experiment does not directly measure conduction, convection and radiation separately. For the underlying distinction between temperature and heat transfer, see OpenStax’s explanation of heat.
Evaluate and propose a useful next test
All three sets have the same 2 °C range, so this simple comparison gives no basis for ranking their precision differently. It does not establish the thermometer’s accuracy. A suitable reference check would address that different question.
To investigate the thickness limitation, propose several measured thicknesses for each material, while keeping the other stated conditions comparable and repeating the measurements. Record the proposal as a next step. Do not write that the improvement “proved” the conclusion unless new results are actually available. An extension calculation gives average cooling rates of 2.8, 2.2 and 1.6 °C per minute respectively; these averages do not show that cooling was constant throughout each interval.
Attempt each task before reading its answer. Use the terms that make your reasoning exact; there is no bonus for inserting all the terms from a group.
1. Calculate density and limit an identification
Task: An insoluble solid has mass 45 g. When fully submerged, it raises the water reading from 28 cm³ to 43 cm³ without trapped bubbles. Calculate its volume and density. A student says, “This proves which element it is.” Evaluate that claim.
Answer: Volume = 43 − 28 = 15 cm³. Density = 45 ÷ 15 = 3 g/cm³. The calculation describes this sample under the stated conditions. Density alone does not prove that it is a particular element: different materials can have similar densities, and the sample might be a compound or mixture. Further relevant evidence would be needed.
2. Explain a balanced chemical equation
Task: Consider the symbolic equation 2Mg + O₂ → 2MgO. Identify reactants and product. Count magnesium and oxygen atoms on each side. For this simplified model, use rounded relative atomic masses Mg = 24 and O = 16. In a closed system, 12 g of magnesium reacts completely with 8 g of oxygen to form only magnesium oxide. Find the product mass. This is a paper exercise.
Answer: Magnesium and oxygen are reactants; magnesium oxide is the product. There are two magnesium atoms and two oxygen atoms on each side of the equation. Product mass is 12 + 8 = 20 g, consistent with conservation of mass. The coefficient before MgO counts formula units; changing the subscript would change the substance represented.
3. Separate correlation from causation
Task: In an invented garden survey, plants near a wall are shorter. They receive less light, but their soil is also drier and they belong to several species. Explain why “shade caused the difference” is too strong. Propose one more informative comparison.
Answer: Light level is associated with plant height, but soil moisture and species also differ. The survey does not isolate the cause. A more informative planned investigation would compare plants of the same species and similar starting size under specified light conditions while controlling water, soil and observation time, with sufficient repeated samples. That is a proposal, not evidence that the investigation has already succeeded.
4. Connect electrical quantities
Task: A hypothetical component has resistance 3 Ω at a potential difference of 6 V. Use I = V ÷ R to find current. In another stated condition the resistance is 6 Ω while the potential difference remains 6 V. Find the new current. Explain why current is not the same quantity as energy.
Answer: The currents are 6 ÷ 3 = 2 A and 6 ÷ 6 = 1 A. Under these stated conditions, doubling resistance halves current. Current is charge passing per unit time; energy is measured in joules. These numerical conditions are supplied for the calculation and do not establish how an arbitrary real component’s resistance changes with temperature.
5. Explain osmosis from supplied evidence
Task: In an invented investigation, equal-sized pieces of fresh plant tissue start at 5.0 g. After equal time, the piece in dilute solution has mass 5.6 g and the piece in concentrated solution has mass 4.4 g. Each is blotted in the same way before weighing. The dilute solution has higher water potential than the cells; the concentrated solution has lower water potential. Assume the cell membranes remain intact. Explain each mass change.
Answer: The first piece gained 0.6 g, consistent with net water movement into its cells by osmosis from higher to lower water potential. The second lost 0.6 g, consistent with net movement out. Water passes through selectively permeable membranes; the explanation does not require the dissolved solute to cross. Do not describe the cells as choosing water. This distinction follows the account of passive transport in OpenStax Biology 2e.
| Problem statement | Repair | Why it matters |
|---|---|---|
| “The experiment proves felt is best.” | Felt produced the smallest mean temperature fall among the tested conditions. | The conclusion stays within the comparison. |
| “The results are accurate because they are close together.” | The results show close agreement; accuracy needs suitable reference evidence. | Precision and accuracy answer different questions. |
| “The plant gets its food from soil.” | The plant absorbs water and mineral ions; photosynthesis produces organic substances. | Mineral uptake and food production are different processes. |
| “The hot water contains heat.” | The water has internal energy; heat transfers because of a temperature difference. | Heat describes a transfer between systems. |
| “Breaking bonds releases energy.” | Breaking bonds requires energy; bond formation releases energy. | The overall reaction depends on both contributions. |
| “The animal adapted because it wanted to survive.” | Inherited variation can affect reproductive success over generations. | Evolution does not require an individual’s intention. |
| “The anomaly should be deleted.” | Check the method and record any justified decision about the result. | Unexpected evidence deserves investigation. |
The bond-energy distinction is explained in OpenStax Chemistry 2e; the relationship between heritable variation and selection is explained in OpenStax Biology 2e. Use these references to resolve a specific uncertainty, then write your own explanation.
Repair in this order: correct the scientific idea, check the calculation or evidence, choose the exact term, then revise grammar and punctuation. A fluent incorrect mechanism remains incorrect. Conversely, a scientifically sound short sentence is a useful starting point for improving expression.
Choose ten terms from the unit you are studying. Use five in the first week and five in the second; reduce the number if explaining the ideas still needs substantial support. This is a practice suggestion, not an IB timetable or a promise of a particular grade.
| Session | What to do | What to keep |
|---|---|---|
| 1: Understand | Match each term to a definition, quantity, diagram or observation. | A short meaning and one boundary on use. |
| 2: Retrieve | Hide the meanings and explain the terms aloud or in writing. | Corrections for missing or confused ideas. |
| 3: Apply | Answer one small data or explanation task using two or three terms. | Your first independent response. |
| 4: Repair | Compare with guidance and fix one scientific and one language issue. | A revised response with the change explained. |
| 5: Transfer | Attempt a new context without the original model. | Evidence of what you can now do unaided. |
Keep sessions short enough to sustain attention; around ten minutes may be a useful starting point. If recall is weak, revisit the same terms instead of automatically adding more. If recall is easy but application is weak, spend the next session on a new problem. The schedule should respond to the learner’s evidence.
Progress means using a term accurately when the surface details change. After the cup investigation, compare two unfamiliar materials using a new supplied data set. After the density exercise, calculate volume from mass and density. After osmosis, explain what would happen when the direction of the water-potential difference reverses. Keep the necessary information available, but remove the original model sentence.
Use a simple record with four columns: date, target terms, independent response and next repair. Mark whether the learner needed a definition, a sentence frame, a calculation prompt or no support. Record the type of help instead of assigning an invented official IB score.
A useful self-check asks: did I name the correct quantity or process; did I use the data accurately; did I show the mechanism or reasoning; and did I limit the claim appropriately? A teacher can then select the next task from the actual weakness. More spelling practice will not solve a confusion between heat and temperature; another definition drill will not necessarily fix a missing causal explanation.
For extended scientific writing, transfer the same habits into paragraphs: state the question or claim, provide relevant evidence, explain the connection and acknowledge a meaningful limitation. Use sources for borrowed facts and distinguish them from your own interpretation.
Is this an official IB list of 200 required words?
No. These are eduKate teaching selections. The official subject framework, your school’s course and the actual task determine what you need to understand and demonstrate. This bank is a companion for learning and communication.
Should an MYP Year 1 learner learn every term?
Choose words that support current learning. Some terms will become useful later or only in particular units. Start with a secure explanation of familiar processes and build towards more specialised language as the underlying concepts develop.
Does a better science essay need more difficult words?
It needs more precise reasoning. A short statement using mean temperature fall correctly is stronger than a crowded paragraph that confuses heat, energy and temperature. Select vocabulary according to what the evidence and question require.
Can I reuse the example sentences?
Use them to notice how a term works, then create a sentence about your own task. Changing a noun while retaining an unsuitable mechanism does not demonstrate understanding. For assessed work, follow your school’s rules about originality and source acknowledgement.
Are all salts the same as table salt?
No. Table salt is a familiar example, but the chemical category is broader. The IUPAC Gold Book identifies salts through their positive and negative ions. Use the substance’s specific name when your answer depends on its properties.
What should I do when a familiar word has a technical meaning?
Write a contrast in your vocabulary record. In science, work has a specific relationship to force and displacement, while power describes a rate of energy transfer. Check the quantity and unit, then build a sentence using that technical sense.
Sources checked: 9 November 2026, Singapore time. Programme and assessment information was checked against the IB’s current public pages. The linked sciences subject brief is an older public document still supplied by the current curriculum page; it is used here for the criterion framework, not to prescribe current examination timings or a universal school syllabus.
- IB MYP overview, sciences curriculum and sciences subject brief: programme scope and assessment purposes.
- IB assessment and examinations and on-screen examinations: distinction between school assessment and optional external routes.
- NIST measurement terminology and SI writing conventions: measurement language and units.
- IUPAC on salts; OpenStax on heat, passive transport, bond energies and adaptive evolution: selected checks on distinctions used in this guide.
The word explanations, learning examples and practice scenarios are written for this guide. The numerical investigations are invented teaching data, not reports of experiments or student outcomes. No vocabulary count guarantees an assessment result.
Your next step: Pick five terms from the science task in front of you. Explain each without copying, use two in one evidence-based response, and repair the most important error before adding another set. For broader writing practice, continue through the Vocabulary Learning Hub.
Continue with vocabulary for your stage
The IB programme overview places PYP at ages 3–12, MYP at 11–16 and DP at 16–19. Schools use different year and grade labels. In this eduKate series, School Years 1–13 are an illustrative school-year route; your school’s programme placement takes priority.
Age 12 vocabulary reference · Fencing Method for vocabulary · Vocabulary Learning Hub
Related subject Essential Word Packs
- PYP Mathematics — 200 words
- PYP Science — 200 words
- MYP Mathematics — 200 words
- MYP Sciences — 200 words — this guide
General Essential Word Packs by school year
School Year 7 · School Year 8 · School Year 9 · School Year 10 · School Year 11