PSLE Science does need precise scientific language—but keywords alone do not earn marks. A correct term must sit inside a correct relationship. Writing “photosynthesis, carbon dioxide, oxygen, energy” without showing the mechanism is not a scientific explanation; it is a vocabulary list.

This page owns one narrow job: helping Primary 6 students use scientific terms accurately in Booklet A reasoning and Booklet B answers. It focuses on command words, cause-and-effect language, comparison wording, evidence phrases, ambiguity control and the difference between vocabulary recall and scientific explanation.

1. Scientific vocabulary is functional

Every important word should do a job: name a concept, describe evidence, express a relationship or answer a command.

2. Vocabulary without relationship is incomplete

Marks usually depend on how terms connect, not how many are present.

3. Keyword dumping is a warning sign

A student may know the chapter but not the mechanism.

4. Start with the command word

Command words determine what kind of language the answer needs.

5. “State” means give the fact

Do not add a long explanation unless needed.

6. “Describe” means report what is observed

Use trend, comparison or sequence language without inventing a cause.

7. “Compare” needs both sides

Use “greater than”, “lower than”, “both”, “whereas”, “while” or equivalent precise relational language.

8. “Explain” needs a mechanism

Cause-and-effect language becomes important.

9. “Predict” needs evidence plus concept

A prediction should not be a guess.

10. “Infer” combines observation and knowledge

State what can reasonably be concluded from the evidence.

11. “Evaluate” requires a judgement with criteria

For investigations, identify a flaw, explain its effect and propose an improvement when asked.

12. Use nouns precisely

Name the plant, force, variable, structure or process instead of relying on vague pronouns.

13. Avoid “it” when two objects are present

Ambiguous reference can destroy an otherwise correct answer.

14. Avoid “thing”

Replace it with the actual scientific entity.

15. Avoid “better” without a criterion

Better at what—faster, stronger, hotter, more suitable, more accurate?

16. Avoid “more” without naming the variable

“More heat energy” and “higher temperature” are not interchangeable statements.

17. Use cause-and-effect language

Useful connectors include “because”, “therefore”, “as a result”, “causes”, “leads to”, “so that” and “hence”—but only when the relationship is scientifically valid.

18. Do not use connectors as decoration

“Therefore” cannot rescue a false mechanism.

19. Evidence language matters

Use “the data show”, “the result indicates”, “compared with”, “the observation was” when the question requires evidence.

20. Evidence comes before mechanism

A strong answer often reads: observed difference → scientific reason.

21. Comparison language should be symmetrical

If A is compared with B, mention both A and B clearly.

22. Sequence language should be explicit

Use “first”, “then”, “next”, “after”, “finally” when order matters.

23. Conditional language prevents overclaiming

Use “under these conditions”, “in this investigation” or “among the tested materials” when the evidence is limited.

24. “Always” needs very strong evidence

Primary Science investigations rarely justify universal claims.

25. “All” may be too broad

Check the tested set before generalising.

26. “Only” can change the meaning completely

Read and use absolute words carefully.

27. Photosynthesis vocabulary

Light energy, water, carbon dioxide, sugar, oxygen, photosynthesis.

28. Photosynthesis mechanism language

“The plant receives less light energy, so the rate/extent of photosynthesis under the setup is reduced” is stronger than “less sunlight, less food”.

29. Avoid “sunlight is food”

Light energy is required for photosynthesis; sugar is produced.

30. Avoid “plants absorb food from soil”

Roots absorb water and mineral salts.

31. Respiration vocabulary

Respiration releases energy from food for life processes.

32. Avoid treating respiration as breathing

Breathing and respiration are related but not identical concepts.

33. Energy vocabulary

Kinetic, potential, light, electrical, sound and heat energy.

34. Energy-conversion language

“Electrical energy is converted into kinetic energy” is clearer than “electricity becomes movement”.

35. Use arrows for energy relationships

Input form → device/process → output form(s).

36. Avoid “energy disappears”

Use transfer or conversion language.

37. Force vocabulary

Frictional force, gravitational force and elastic spring force are key P6 terms.

38. Force-answer language

Name the force, then state the effect on motion or shape.

39. Avoid “force is movement”

A force can change motion; it is not motion itself.

40. Environment vocabulary

Producer, consumer, decomposer, population, community, habitat, adaptation, food chain, food web.

41. Food-chain arrow language

Students should know what the arrows represent in the question’s convention and trace feeding relationships consistently.

42. Avoid loose population language

“More animals” may be too vague; name the population.

43. System vocabulary

Part, function, transport, absorption, digestion, respiration, circulation and electrical circuit should be used at the appropriate primary level.

44. Function language

“The roots absorb water” is more precise than “roots help the plant”.

45. Circuit vocabulary

Closed circuit, conductor, insulator, electrical component, battery/cell and wire should be used clearly.

46. Avoid “electricity flows out” when energy is the tested idea

Read whether the question asks about circuit function or energy conversion.

47. Heat vocabulary

Heat energy, temperature, gain, lose, warmer, cooler, expansion and contraction should not be casually substituted for one another.

48. Light vocabulary

Light source, reflection, shadow and path of light need precise reference.

49. Matter vocabulary

Solid, liquid, gas, melting, freezing, evaporation and condensation should be tied to observable changes.

50. Water-cycle language

Use evaporation and condensation accurately rather than “water disappears” or “clouds make water”.

51. Inquiry vocabulary — changed variable

Call it the factor deliberately changed if formal variable terminology is not required in the question.

52. Inquiry vocabulary — measured outcome

Name exactly what was measured or observed.

53. Inquiry vocabulary — control

State what must remain the same and why it matters.

54. Inquiry vocabulary — fair test

Explain fairness through controlled conditions, not the phrase “it is fair”.

55. Inquiry vocabulary — reliability

Repeated trials can help when the method itself is sound.

56. Inquiry vocabulary — anomaly

An unusual result should be investigated rather than automatically removed.

57. Inquiry vocabulary — conclusion

A conclusion should answer the test question using the data.

58. Inquiry vocabulary — improvement

State the flaw, why it affects the test, and the repair.

59. Graph vocabulary

Increase, decrease, remain constant, peak, lowest, highest, directly compared, trend.

60. Table vocabulary

Use exact row/column labels in the answer when necessary.

61. Avoid “goes up” in formal answers when “increases” is clearer

Conversational language can be replaced with precise scientific wording.

62. Avoid “a lot”

Use the actual comparative relationship or numerical evidence.

63. Avoid “same” without naming what is the same

Same temperature? Same mass? Same number? Same duration?

64. Vocabulary learning should use retrieval

Cover the definition and reconstruct it from memory.

65. Vocabulary learning should use examples

A term is stronger when the student can recognise it in context.

66. Vocabulary learning should use counterexamples

Knowing what a term does not mean strengthens boundaries.

67. Vocabulary learning should use sentence completion carefully

Do not reduce Science to memorised phrases; change the context afterward.

68. Vocabulary learning should use diagrams

Labeling and explaining a diagram links words to structures and processes.

69. Vocabulary learning should use oral explanation

If the child can say it accurately, the next step is precise writing.

70. Vocabulary learning should use written reconstruction

Close the glossary and write the term inside a mechanism.

71. Build a personal confusion list

Examples: heat/temperature, food/energy, force/motion, observation/inference, adaptation/habitat.

72. Compare confusing pairs explicitly

Write what each term means, how they differ and one example.

73. Keep command words separate from topic vocabulary

“Explain” is a task word; “photosynthesis” is a concept word.

74. Keep evidence words separate from mechanism words

“The data show” introduces evidence; “because” introduces causal reasoning.

75. Use a three-layer answer check

Term: correct vocabulary? Relationship: correct mechanism? Evidence: tied to the question?

76. Use a pronoun check

Could the marker misunderstand what “it” refers to?

77. Use a boundary check

Did the answer claim more than the evidence?

78. Use a command check

Did the response do the job requested?

79. Use an answer-compression check

Can irrelevant words be removed without losing the mechanism?

80. Use a transfer check

Can the same vocabulary be used correctly in a new context?

81. Parent support — ask for meaning, not spelling only

“What does this term explain?” is more useful than “Can you spell it?”

82. Parent support — ask for a contrasting term

This helps expose confusion.

83. Tutor support — correct language after diagnosing concept

Do not polish a sentence that contains wrong Science.

84. Tutor support — preserve the student’s own wording where accurate

There is rarely only one acceptable sentence.

85. Tutor support — avoid teaching magical keywords

Students should understand why each term belongs.

86. Tutor support — model multiple correct phrasings

This teaches the invariant mechanism beneath the wording.

87. Tutor support — retest without the word bank

Independent retrieval is the goal.

88. Where vocabulary fits in the P6 system

Use Punggol Science Tutor Primary 6 for the broader diagnostic tutorial operating system.

89. Where vocabulary fits in Booklet B repair

Use PSLE Science Small-Group Paper Clinic for answer surgery and reconstruction.

90. Final principle

Scientific vocabulary earns its value when it makes reasoning more precise. Learn the term, understand its boundary, place it inside a correct relationship, connect it to evidence and remove it when it does not belong.

Do not collect keywords. Build explanations.