Secondary 1 Science vocabulary in Singapore is the language used to ask testable questions, measure fairly, explain matter and life, and connect scientific ideas to everyday events. The 200 defined words and terms in this guide cover experiments, laboratory measurements, particle theory, materials, energy, forces, cells, ecosystems, electricity, and scientific data.
This is an independently curated learning resource, not an MOE-mandated list of 200 words. Singapore’s G1 and G2/G3 lower-secondary Science syllabuses do not all use exactly the same topic sequence or level of detail. Your child’s school outline and teacher are the best guide to what is immediately assessed. This glossary helps students understand the language before they try to remember explanations.
- 200 simple definitions organised into ten searchable themes
- Worked science examples that separate observations, inferences and conclusions
- Four-week learning route, laboratory safety habits, parent checks and official MOE sources
All 200 Secondary 1 Science vocabulary words and meanings
The sections contain exactly 200 distinct entries. Some terms are useful for later secondary learning or extension beyond a particular Secondary 1 class. Learn your current school topics first, then return to the broader glossary when a new context makes a word relevant.
1. Scientific inquiry and lab language — words 1–20
- science — the systematic study of natural phenomena through evidence.
- observation — information noticed or measured directly.
- inference — a reasonable explanation drawn from observations.
- hypothesis — a testable possible explanation for a question.
- prediction — an expected outcome based on an idea or model.
- investigation — a planned process for answering a scientific question.
- experiment — a practical test using a defined method.
- variable — a factor that may change during an investigation.
- independent variable — the factor deliberately changed in a test.
- dependent variable — the result measured in response to a change.
- controlled variable — a factor kept the same for a fair comparison.
- fair test — a comparison where other relevant factors are held constant.
- control — a comparison condition used to judge an effect.
- method — the steps used to carry out an investigation.
- procedure — an ordered sequence of laboratory actions.
- apparatus — the instruments used for practical work.
- equipment — tools and materials needed for a task.
- safety — measures that reduce the chance of injury.
- hazard — a source of possible harm.
- evidence — observations or data that support an explanation.
2. Measurement and trustworthy readings — words 21–40
- SI unit — an internationally agreed measurement unit.
- measurement — a value obtained by comparing with a standard.
- accuracy — closeness of a reading to the true value.
- precision — closeness of repeated measurements to one another.
- resolution — the smallest change a device can show.
- repeatability — how consistently the same method gives similar results.
- validity — whether a test or measure answers its intended question.
- error — the difference between a result and an accepted value.
- uncertainty — the range of doubt around a measurement.
- calibration — checking or adjusting an instrument against a standard.
- scale — the marked intervals on a measuring instrument.
- reading — a value taken from an instrument.
- meniscus — the curved surface of a liquid in a narrow container.
- thermometer — an instrument used to measure temperature.
- measuring cylinder — a graduated container used to measure liquid volume.
- balance — an instrument used to determine mass.
- stopwatch — a device used to measure elapsed time.
- length — distance along a single dimension.
- volume — the amount of space occupied.
- mass — the quantity of matter in an object.
3. Particles, matter and changing state — words 41–60
- matter — anything that has mass and occupies space.
- substance — a particular kind of material.
- solid — a state with a fixed shape and volume.
- liquid — a state with fixed volume but changeable shape.
- gas — a state without fixed shape or volume.
- particle — a tiny unit used to model matter.
- atom — the basic chemical unit of an element.
- molecule — a group of atoms chemically bonded together.
- element — a pure substance made of one type of atom.
- compound — a substance containing different elements chemically combined.
- mixture — materials combined without chemical bonding between components.
- pure substance — matter consisting of only one chemical substance.
- density — mass divided by volume.
- compressibility — how much volume decreases under pressure.
- diffusion — spreading caused by random particle movement.
- melting — change from solid to liquid.
- freezing — change from liquid to solid.
- evaporation — escape of liquid particles into gas at the surface.
- boiling — rapid vaporisation occurring throughout a liquid.
- condensation — change from gas to liquid.
4. Properties of materials and separation — words 61–80
- physical property — a characteristic observed without changing chemical identity.
- chemical property — a characteristic describing how a substance reacts.
- hardness — resistance to scratching or indentation.
- flexibility — ability to bend without breaking.
- elasticity — ability to return to original form after deformation.
- conductivity — ability to transfer electricity or heat.
- solubility — how much material can dissolve in a solvent.
- solvent — a liquid that dissolves another substance.
- solute — the substance dissolved in a solvent.
- solution — a uniform mixture of solute and solvent.
- saturated solution — a solution unable to dissolve more solute under given conditions.
- filtration — separation using a barrier that traps solid particles.
- residue — material left behind after separation.
- filtrate — liquid that passes through a filter.
- distillation — separation involving vaporisation and condensation.
- chromatography — separation by different movement through a medium.
- magnetism — the force-related property involving magnets or magnetic fields.
- transparency — allowing light to pass so objects are seen clearly.
- opacity — blocking light from passing through.
- viscosity — a fluid’s resistance to flowing.
5. Energy, heat and transfers — words 81–100
- energy — the capacity to cause physical change or do work.
- kinetic energy — energy associated with motion.
- potential energy — stored energy due to position or condition.
- gravitational potential energy — energy associated with position in a gravitational field.
- elastic potential energy — energy stored when an object is stretched or compressed.
- thermal energy — energy associated with microscopic particle motion and arrangement.
- heat — energy transferred because of a temperature difference.
- temperature — a measure related to how hot or cold something is.
- energy transfer — movement of energy between objects or systems.
- conduction — energy transfer through particle interactions within material.
- convection — heat transfer by bulk movement of a fluid.
- radiation — energy transfer through electromagnetic waves.
- energy conversion — changing energy from one form into another.
- conservation of energy — the principle that total energy is not created or destroyed.
- energy efficiency — useful energy output divided by energy input.
- renewable energy — energy from sources naturally replenished on useful timescales.
- non-renewable energy — energy from resources not quickly replaced.
- work — energy transferred when a force acts through a displacement.
- power — the rate of transferring energy or doing work.
- insulation — material or design used to reduce unwanted energy transfer.
6. Forces, speed and movement — words 101–120
- force — a push or pull that can affect motion or shape.
- push — a force tending to move something away.
- pull — a force tending to draw something closer.
- gravity — attraction between objects with mass.
- friction — a contact force opposing relative surface motion.
- air resistance — a drag force from movement through air.
- resultant force — the combined overall force acting on an object.
- balanced forces — forces that together produce zero resultant force.
- unbalanced forces — forces giving a non-zero resultant force.
- acceleration — the rate at which velocity changes.
- deceleration — a reduction in speed over time.
- speed — distance travelled per unit time.
- velocity — speed with a specified direction.
- displacement — change in position including direction.
- distance — the total length of a travelled path.
- motion — change in position over time.
- inertia — an object’s tendency to resist changes in velocity.
- contact force — a force acting through physical interaction.
- non-contact force — a force acting without direct surface contact.
- newton — the SI unit of force.
7. Cells, living systems and life processes — words 121–140
- cell — the smallest structural and functional unit of life.
- nucleus — the cell structure containing genetic material in many cells.
- cytoplasm — the material inside a cell where processes occur.
- cell membrane — the boundary controlling movement into and out of a cell.
- cell wall — a rigid outer layer supporting some cells.
- chloroplast — a plant-cell structure where photosynthesis occurs.
- vacuole — a membrane-bound compartment storing substances.
- tissue — a group of similar cells performing related functions.
- organ — a body structure containing tissues for a particular task.
- organ system — a group of organs working together.
- organism — an individual living thing.
- unicellular — made of one cell.
- multicellular — made of many cells.
- specialised cell — a cell adapted for a particular function.
- photosynthesis — the process using light to make food in plants.
- respiration — chemical processes releasing usable energy in cells.
- reproduction — the production of new organisms.
- nutrient — a substance required for growth or normal function.
- digestion — breaking food into substances the body can absorb.
- circulation — movement of materials around a body.
8. Habitats, ecology and human impact — words 141–160
- environment — the surroundings and conditions affecting living things.
- habitat — the place where an organism naturally lives.
- ecosystem — living organisms and their non-living environment interacting.
- population — members of one species living in a defined area.
- community — populations of different species living together.
- biodiversity — the variety of living organisms in an area.
- producer — an organism that makes its own food.
- consumer — an organism obtaining food from other organisms.
- decomposer — an organism breaking down dead organic material.
- food chain — a sequence showing feeding relationships.
- food web — connected food chains in an ecosystem.
- predator — an animal that hunts other organisms for food.
- prey — an organism eaten by a predator.
- adaptation — a characteristic helping survival or reproduction.
- competition — organisms seeking the same limited resource.
- pollution — harmful introduction of substances or effects into an environment.
- contamination — presence of unwanted material in a sample or place.
- conservation — protection and careful management of natural resources.
- sustainability — using resources in ways that can continue long term.
- climate change — lasting shifts in patterns of climate.
9. Electricity, light and sound — words 161–180
- electric current — the rate of flow of electric charge.
- electrical circuit — a connected path allowing current to flow.
- conductor — a material allowing charge or heat to pass readily.
- insulator — a material resisting charge or heat transfer.
- battery — a source that supplies electrical energy from chemical reactions.
- dry cell — a common portable electrochemical source of electrical energy.
- switch — a device used to open or close a circuit.
- bulb — a device that changes electrical energy into light.
- series circuit — a circuit whose components share one current path.
- parallel circuit — a circuit with more than one branch.
- voltage — potential difference between two points in a circuit.
- resistance — opposition to the flow of electric current.
- circuit diagram — a drawing using standard symbols for components.
- sound wave — a travelling disturbance that transfers sound energy.
- vibration — repeated back-and-forth movement.
- pitch — how high or low a sound is perceived.
- loudness — how strong a sound is perceived.
- reflection — a wave changing direction at a boundary.
- refraction — a wave changing direction when its speed changes.
- shadow — a region where light is blocked by an object.
10. Data, explanations and scientific judgement — words 181–200
- source — where a scientific statement or measurement comes from.
- claim — a statement that can be supported or tested.
- correlation — a statistical association between two variables.
- causation — a relationship where one factor produces an effect.
- anomaly — an observation differing from the expected pattern.
- outlier — a measurement unusually distant from others.
- trend — the general direction shown by data.
- pattern — a repeated or regular feature in observations.
- data — recorded measurements or observations.
- table — information organised into rows and columns.
- graph — a visual display of relationships between values.
- qualitative — describing properties rather than numerical amounts.
- quantitative — expressed in measured or counted numbers.
- conclusion — an answer drawn from findings and evidence.
- evaluation — judging the strengths and weaknesses of a method.
- limitation — a restriction affecting what results can establish.
- repeat trial — another run of the same procedure.
- replication — a separate attempt to reproduce a finding.
- peer review — evaluation of research by other knowledgeable people.
- model — a simplified representation used to explain or predict.
Why scientific vocabulary matters more than memorising labels
Science language carries distinctions that ordinary conversation often blurs. A child might say that a table is ‘cold’. Science asks whether the student means low temperature, rapid heat transfer, or the feeling of touching a material that conducts energy effectively. These are related but different ideas. Exact vocabulary makes it possible to explain why an observation occurs instead of only describing how it feels.
For example, heat is energy transferred because of a temperature difference. Temperature is a measure of the thermal state of a system. A steel spoon and a plastic spoon can be left in the same room and have similar temperatures, yet the steel may feel cooler to the hand because energy transfers through it more rapidly. The everyday sensation is useful evidence, but the scientific explanation requires the right terms.
Worked example 1: a fair test about dissolving
Question: Does water temperature affect how quickly a fixed quantity of sugar dissolves? Independent variable: water temperature. Dependent variable: time taken for the sugar to dissolve, under a clearly specified procedure. Controlled variables: amount of sugar, volume of water, type of sugar, container and stirring conditions. Repeat trials and compare measurements. A warm-water result may suggest a pattern, but one trial is not enough to claim a universal rule.
Here fair test is not just a phrase to memorise. If you stir one cup but not the other, the investigation can no longer cleanly separate water-temperature effects from stirring effects. If the thermometer is read incorrectly, the experiment may be repeatable without being accurate. If you never define what ‘fully dissolved’ means, another student cannot reproduce the method reliably.
Worked example 2: observation, inference and explanation
Observation: droplets appear on the outside of a cold glass. Inference: some water vapour in the surrounding air has changed to liquid on the cold surface. Explanation: the surface cools the nearby air and makes condensation possible. The droplets are not usually evidence that the glass is leaking. The word condensation names the change of state, while the reasoning explains why the observation is expected.
The same thinking helps with science news. If a headline says that two events are correlated, it does not automatically show causation. Ask whether a plausible mechanism, fair comparison and sufficiently strong evidence connect the variables. A sound conclusion can be cautious and still be scientifically useful.
Worked example 3: cells and function
A cell is the basic unit of life, while a tissue is a group of cells working in a related way and an organ combines tissues to perform larger tasks. When comparing plant and animal cells, identify structures and their functions rather than relying on a single diagram from memory. For example, plant cells commonly have a cell wall, while animal cells lack one. Plant cells capable of photosynthesis contain chloroplasts, but it is incorrect to say that every plant cell contains chloroplasts. A root cell is a useful counter-example.
If a question asks what a specialised cell is adapted to do, connect the feature to the function: a root hair cell has an extended surface for absorption. Naming the organelle without explaining the job is incomplete reasoning. The word adaptation is valuable because it forces the student to explain a relationship rather than list isolated facts.
Worked example 4: materials, filtration and solutions
A mixture of sand and water may be separated by filtration: the sand is retained as the residue and the water that passes through is the filtrate. However, ordinary filtration does not remove dissolved salt from water. A solution contains a solute dissolved in a solvent; its tiny dissolved particles can pass through many filter papers. Recognising the difference between dissolved and undissolved substances helps students choose a meaningful separation method.
This is not only a test question. Understanding dissolved substances matters when reading about drinking-water treatment, cleaning products, cooking and pollution. A student can ask, ‘What material are we trying to separate, and what property is different?’ That question gives purpose to every named method.
Worked example 5: forces, motion and energy
Imagine pushing a small trolley on a level floor. Friction opposes its sliding or rolling motion. If forward and backward forces are balanced, the resultant force is zero. That does not necessarily mean the trolley must be at rest: it can continue at constant velocity. If the resultant force is non-zero, its velocity changes. Treating balanced forces as a synonym for ‘not moving’ is a common conceptual error.
In a moving trolley, kinetic energy is associated with motion. If it slows, energy is transferred to the surroundings through interactions such as friction. Energy has not simply vanished. Scientific descriptions become more accurate when students track the system and the energy pathway instead of saying only that energy is ‘used up’.
Worked example 6: an ecosystem is a set of relationships
In a simplified food chain, grass → grasshopper → frog → snake, the arrows represent transfer of energy through feeding. Grass is a producer, the grasshopper a consumer, and the frog both a predator of the grasshopper and prey for a snake. A food web connects many such relationships and is a more realistic representation of an ecosystem. Removing a species can affect other populations, but the direction and size of the effect depend on the specific system.
Singapore contexts make ecology tangible. A student observing a park pond can notice shade, plants, insects and human activity. Not every observation is safe or ethical to investigate by collecting specimens. Useful science can begin with photographs, carefully recorded counts, environmental care and questions that do not disturb habitats.
G1, G2 and G3 Science: choose vocabulary by actual lesson
MOE’s G1 lower-secondary Science syllabus includes practical laboratory skills and modules such as our environment, machines around us, and our body and health. The G2/G3 lower-secondary Science syllabus is organised through broader ideas such as scientific endeavour, diversity, models, interactions and systems. Some terms in this glossary are used as preparation for future content. A parent should check the child’s current chapter rather than assuming a single Secondary 1 national test covers every entry.
At any subject level, students benefit from learning what a diagram or model leaves out. A drawing of particles may show them as coloured balls; real particles do not have those colours simply because the diagram uses them. This is the difference between a model and the world being represented. The better the vocabulary, the easier it becomes to discuss the strengths and limitations of a scientific explanation.
Lab safety and measuring with confidence
- Read the teacher’s instructions, identify hazards and wear the protective equipment required for the activity.
- Never taste or smell chemicals directly; follow the teacher’s approved method and handling rules.
- Choose an appropriate measuring instrument and unit; check the scale before recording a value.
- For a liquid in a measuring cylinder, read at eye level using the appropriate part of the meniscus.
- Record observations honestly, including unexpected values; do not delete inconvenient data merely to make a neat graph.
- Make a conclusion that answers the question, refers to evidence and recognises important limitations.
Four-week vocabulary and science-thinking plan
| Week | Learning focus | Evidence of understanding |
|---|---|---|
| 1 | Investigation terms and measurements. | Identify variables and explain a fair comparison. |
| 2 | Particle ideas, changing states and materials. | Distinguish evaporation, boiling and condensation with examples. |
| 3 | Cells, life processes and ecology. | Explain the function of structures and feeding relationships. |
| 4 | Energy, forces, electricity and interpreting data. | Write a conclusion with evidence and one limitation. |
A useful daily routine is ten minutes: select five terms, explain them in your own words, sketch one labelled example, then answer one unseen ‘why’ question. Revisit yesterday’s terms briefly. Do not turn a learning list into a race to finish 200 words. A student who can explain why a test is fair has learned more than one who can recite the phrase but cannot identify the variables.
Common diagnostic mistakes
- Observation becomes opinion: ‘The plant is unhealthy’ may need observable signs such as yellowing leaves or reduced height.
- Hypothesis becomes conclusion: a prediction is made before testing; a conclusion follows examination of results.
- Mass becomes weight: these are related physical quantities but not identical; distinguish the unit and measured property.
- Heat becomes temperature: separate energy transfer from a temperature reading.
- Dissolving becomes melting: sugar dissolving in water is not the same process as ice melting.
- Correlation becomes causation: a data pattern alone may not establish a mechanism.
- Model becomes reality: use diagrams for explanation while recognising their simplifications.
Frequently asked questions
Is this an official list of 200 MOE Secondary 1 Science words?
No. It is an original reference glossary built around science concepts and investigative language, not an MOE or SEAB compulsory word list.
Are all the topics tested in Secondary 1?
No. Content varies by G1, G2 and G3 pathways and individual school schedules. Some terms are introduced as future-learning extensions.
How can students answer science explanation questions?
Name the observation, use the correct scientific concept, connect cause and effect, and refer to evidence where the task requires it.
What is a fair test?
A comparison designed so that the factor of interest is changed while other relevant factors remain controlled.
What is the difference between accuracy and precision?
Accuracy concerns closeness to a true value. Precision concerns closeness among repeated readings.
Should a student memorise all 200 terms?
Prioritise terms in the current school unit, then practise their use and revisit weak words. There is no universal one-month quota.
Does Science matter beyond examinations?
Yes. It helps people interpret health information, electricity use, environmental questions, data, transport and new technology.
When should tuition be considered?
After identifying whether the student’s difficulty is a vocabulary gap, a missing concept, poor method design, inaccurate observation or weak explanation.
Official source documents and next reading
MOE sources: G1 Lower Secondary Science syllabus; G2 and G3 Lower Secondary Science syllabus; MOE secondary school guidance. Ask the school for its particular term sequence and laboratory instructions.
Within eduKate, continue to Vocabulary: Words, Meanings and Mastery, Vocabulary Learning Hub, Science learning guides, Secondary 1 Mathematics vocabulary for graphs and measurement.
Reviewed November 2026. Definitions are simplified teaching descriptions; worked examples are original illustrations rather than official examination questions. Check the current school syllabus for scope.