Science vocabulary is not a list of difficult words sitting beside the real subject. It is part of the thinking system of Science. The core aim of Science mastery is for students to understand scientific terms precisely enough to notice differences, interpret evidence, connect cause and effect, explain mechanisms and avoid replacing one vague word with another.
For students and parents searching for science vocabulary, scientific vocabulary, science terms, science definitions, science keywords, PSLE Science vocabulary or Secondary Science vocabulary, the most useful shift is to move beyond “word = definition”. Real vocabulary mastery means the learner can recognise the word, explain it, distinguish it from similar words, use it in a scientific relationship and retrieve it when the question does not announce the term.
A student can memorise “evaporation = change from liquid to gas” and still fail to recognise evaporation in a new context. Vocabulary becomes powerful only when it connects to phenomena, models and evidence.
The 60-Second Science Vocabulary Method
For every important term, learn six things:
- Meaning: what the term means.
- Example: a clear case.
- Non-example: a tempting case that does not fit.
- Relationship: what causes it, affects it or follows from it.
- Representation: how it appears in a diagram, equation, graph or experiment.
- Use: how the term belongs in a scientific sentence.
This turns vocabulary from memorised labels into a usable network.
Wait, What? Knowing the Definition Is Not the Same as Knowing the Word?
Correct.
Suppose Clara can recite:
“Condensation is the change of state from gas to liquid.”
Then she sees water droplets forming on a cold surface and says the water “came through the bottle”.
The definition is stored, but the concept is not yet available for recognition and explanation.
Vocabulary mastery therefore needs transfer.
The learner must be able to move:
word → meaning → example → evidence → mechanism → new context.
Why Science Vocabulary Matters So Much
Science uses ordinary-looking words with technical meanings.
Examples include:
- work;
- power;
- force;
- energy;
- mass;
- weight;
- theory;
- model;
- solution;
- concentration;
- current;
- resistance;
- adaptation;
- response;
- reliability; and
- validity.
If a learner imports the everyday meaning into a technical question, reasoning can drift immediately.
Vocabulary precision protects concept precision.
Science Vocabulary Has Different Jobs
Object words
cell, nucleus, conductor, molecule, lens, circuit.
Process words
diffuse, evaporate, condense, react, respire, absorb, transfer.
Quantity words
mass, temperature, speed, concentration, current, voltage.
Relationship words
increase, decrease, proportional, inversely related, equal, greater than, limiting.
Evidence words
observation, inference, anomaly, trend, reliability, uncertainty.
Instruction words
state, describe, explain, compare, calculate, predict, evaluate.
Students need all of them.
Many “Science problems” are actually failures in one vocabulary category.
Instruction Words Can Change the Entire Answer
Consider:
- State: give the requested fact or result directly.
- Describe: say what is observed or what pattern appears.
- Explain: give the scientific reason or mechanism.
- Compare: identify relevant similarities or differences.
- Predict: state an expected outcome based on evidence or a model.
- Evaluate: judge quality, strength or limitations using criteria and evidence.
A student who answers an “explain” question with only a description may know the Science but still miss the task.
Vocabulary includes the language of the question itself.
Near-Synonyms Are Dangerous in Science
Scientific terms can sound similar while doing different jobs.
Examples:
- mass vs weight;
- heat vs temperature;
- speed vs velocity;
- evaporation vs boiling;
- melting vs dissolving;
- breathing vs respiration;
- observation vs inference;
- accuracy vs precision;
- reliability vs validity;
- hypothesis vs prediction;
- correlation vs causation.
Contrast pairs are one of the fastest ways to sharpen vocabulary.
Do not ask only, “What does X mean?”
Also ask, “How is X different from Y?”
Relationships Matter More Than Noun Collections
Students often study Science by memorising nouns.
But explanations need relationships.
Consider the difference between these two lists.
Nouns: light, plant, chlorophyll, carbon dioxide, glucose.
Relationships: absorbs, enters, reacts, produces, increases, limits, depends on.
The second list is what turns vocabulary into mechanism.
This is why Scientific Explanation and vocabulary mastery are inseparable.
How to Learn a Science Term Properly
Take diffusion.
Meaning
Learn the precise syllabus-appropriate definition.
Example
Choose a familiar case where diffusion occurs.
Non-example
Choose a process that may look similar but is driven differently.
Conditions
What factors affect the process?
Representation
How would particles or concentration be shown?
Evidence
What observation would be consistent with diffusion?
Use
Write one sentence that explains a real scenario using the term accurately.
That is much stronger than copying the definition repeatedly.
Use Diagrams to Build Vocabulary Networks
Some Science words are easiest to understand spatially.
For example, a labelled cell diagram connects:
- structure names;
- locations;
- functions;
- relationships between parts; and
- differences between cell types.
Students should not only label the diagram. They should explain what each label does and how the parts work together.
The diagram turns a vocabulary list into a system.
Use Graphs to Learn Relationship Vocabulary
Graphs teach words such as:
- increase;
- decrease;
- constant;
- rate;
- gradient;
- maximum;
- minimum;
- plateau;
- direct relationship;
- inverse relationship; and
- anomaly.
These words should be tied to actual patterns, not memorised abstractly.
Use Data Interpretation for the dedicated owner.
Use Experiments to Learn Method Vocabulary
Terms such as:
- independent variable;
- dependent variable;
- controlled variable;
- fair test;
- repeat;
- reliability;
- validity;
- accuracy; and
- anomaly
become much easier when attached to a real investigation.
Do not learn “controlled variable” as a definition only. Ask what factor could otherwise create an alternative explanation for the result.
See Science Experiments.
Primary Science Vocabulary
At Primary level, students benefit from:
- precise everyday-to-scientific distinctions;
- picture–word connections;
- sentence use;
- cause-and-effect vocabulary;
- comparison words;
- process words; and
- frequent retrieval in new examples.
A word learned only for Friday’s spelling test is not yet a scientific tool.
Lower Secondary Science Vocabulary
Secondary students encounter more abstraction.
Words increasingly refer to:
- unseen particles;
- models;
- quantitative relationships;
- energy systems;
- cell processes;
- chemical change;
- forces;
- experimental quality; and
- formal representations.
Students should learn how technical terms connect across chapters.
For example, “rate” appears in reactions, motion, biological processes and data interpretation. The contexts differ, but the relational idea remains useful.
Upper Secondary Vocabulary: Precision Becomes More Important
Biology, Chemistry and Physics develop specialised languages.
Precision matters because small word differences can signal different concepts.
A useful routine is:
define → distinguish → represent → apply → explain.
Students who do this consistently build vocabulary and conceptual structure together.
Flashcards That Actually Help
Weak flashcard:
Front: Diffusion
Back: copied textbook definition.
Better flashcard set:
- What is diffusion?
- Which diagram shows diffusion and why?
- How is diffusion different from bulk flow?
- What happens to diffusion rate when a relevant gradient changes?
- Which observation would support diffusion in this scenario?
One term becomes several retrieval routes.
Vocabulary Retrieval Should Be Bidirectional
Do not practise only:
word → definition.
Also practise:
definition → word.
diagram → word.
example → word.
word → example.
misconception → correction.
question context → relevant term.
This makes retrieval more flexible.
Science Vocabulary and English Language
Science is taught through language, so general English proficiency matters.
But scientific vocabulary has additional demands:
- technical meanings;
- precise relationships;
- discipline-specific command words;
- symbolic notation; and
- careful distinctions between certainty levels.
A learner may understand everyday English well and still need explicit instruction in scientific language.
Sentence Frames: Useful Scaffolds, Not Permanent Crutches
Frames can help younger or developing learners:
“As ___ increases, ___ decreases.”
“The results show ___ because ___.”
“This is a fairer comparison because ___ is kept constant.”
“The observation suggests ___, but does not show ___.”
Use the frame to reveal structure, then gradually remove it.
The aim is flexible language, not dependence on one memorised sentence.
Common Science Vocabulary Mistakes
Memorising definitions without examples
The student recognises the word but cannot apply it.
Using everyday meanings
Technical terms such as work, power or theory are interpreted casually.
Learning nouns but not relationships
The answer contains many terms but no mechanism.
Confusing near-synonyms
Related but distinct concepts become interchangeable.
Using keywords as decoration
The word is correct but does not connect to the evidence.
Copying definitions that are too advanced
The learner can recite the wording but cannot explain it in simpler language.
Ignoring command words
The student knows the Science but performs the wrong task.
A Better Science Vocabulary Notebook
Use five columns:
- Term
- Meaning in my own words
- Example or diagram
- Common confusion
- One sentence using the term scientifically
Add a sixth column for older students:
Related quantities, equations or evidence patterns.
This creates a working glossary rather than a dictionary copy.
How to Revise Science Vocabulary
Use short, frequent retrieval:
- five terms from yesterday;
- five from last week;
- five mixed from older topics;
- two contrast pairs;
- one diagram labelling task;
- one explanation using three target terms.
Then apply the terms in questions.
Vocabulary that never enters problem solving remains fragile.
For the broader revision owner, see Science Revision.
Frequently Asked Questions
Why is Science vocabulary important?
Scientific terms let students represent concepts and relationships precisely. Weak vocabulary can cause reading, reasoning and explanation errors even when general understanding is developing.
How can I learn Science vocabulary quickly?
Use retrieval, examples, contrast pairs, diagrams and sentence application. Avoid relying only on repeated copying.
Should I memorise definitions word for word?
Some school contexts require precise wording, but understanding should come first. The learner should also be able to explain the term, identify examples and use it correctly in context.
What are Science keywords?
They are important technical terms and relationship words used to represent scientific concepts accurately. Keywords are useful, but they do not replace complete reasoning.
Why do I know the keyword but still lose marks?
The answer may be missing the relationship or mechanism that connects the keyword to the given evidence.
How do I remember similar Science terms?
Study them as contrast pairs. Write the exact difference, one example of each and one common confusion.
Are command words part of Science vocabulary?
Yes. Words such as describe, explain, compare, predict and evaluate specify the kind of thinking and response required.
Useful eduKateSG Routes
- Science Learning Hub
- How Science Works
- Scientific Explanation
- Data Interpretation
- Science Experiments
- Science Revision
- How to Improve Science Skills Faster
The Core Aim
Science vocabulary mastery is not winning a spelling contest with difficult words.
It is being able to use precise language to think precisely.
Know the term.
Know what it is not.
See it in a diagram.
Recognise it in evidence.
Connect it to relationships.
Use it in an explanation.
Retrieve it when the question changes.
That is the core aim: words become scientific tools rather than decorations.
Properly taught kids shine a bright light into the future.