The Cycles Idea | Do Not Memorise the Circle—Understand the Transition

Students often recognise a familiar cycle diagram yet become uncertain when the picture changes. That happens when the labels were learned but the transitions were not. A stronger learner can explain why a seed reaches the next stage, what causes liquid water to become water vapour, or which condition must be present for a particular change to happen.

The core question is therefore not only “What comes next?” It is “What changed, under what condition, and what evidence tells us the system has entered the next stage?”

Top 100 Cycles Keywords | Core First, Enrichment Later

Terms 1–40 form the strongest Primary Science core/bridge set for life cycles, reproduction, matter and water. Terms 41–60 extend the same reasoning. Terms 61–100 preserve useful vocabulary from the older 2024 page for wider Science enrichment and later study.

1–20 | Life Cycles and Reproduction

1. Cycle — a sequence of stages or changes that repeats.
2. Life cycle — the stages through which a living thing develops and reproduces.
3. Stage — one distinguishable part of a cycle.
4. Egg — an early reproductive stage in the life cycles of many animals.
5. Young — a developing organism that has not reached the adult stage.
6. Adult — mature stage capable of reproduction in many life cycles.
7. Growth — increase in size and development of an organism.
8. Development — changes in structure or function as an organism matures.
9. Reproduction — process by which living things produce new individuals of their kind.
10. Parent — organism that produces offspring.
11. Offspring — new organism produced by one or more parents.
12. Seed — plant reproductive structure containing an embryo and stored material.
13. Germination — beginning of seed growth under suitable conditions.
14. Seedling — young plant after germination.
15. Mature plant — developed plant capable of reproduction.
16. Flower — reproductive structure of a flowering plant.
17. Pollination — transfer of pollen from anther to stigma.
18. Fertilisation — joining of male and female reproductive cells.
19. Fruit — plant structure that develops after fertilisation and may contain seeds.
20. Seed dispersal — movement of seeds away from the parent plant.

21–40 | Matter, Changes of State and Water

21. Matter — anything that has mass and occupies space.
22. Solid — matter with fixed shape and fixed volume under ordinary conditions.
23. Liquid — matter with fixed volume but no fixed shape.
24. Gas — matter with no fixed shape and no fixed volume.
25. State of matter — physical form in which matter exists.
26. Melting — change from solid to liquid.
27. Freezing — change from liquid to solid.
28. Evaporation — change from liquid to gas at the surface of a liquid.
29. Condensation — change from gas to liquid.
30. Water cycle — continuous movement and change of water in the environment.
31. Water vapour — gaseous form of water.
32. Cloud — visible collection of tiny water droplets or ice crystals in the atmosphere.
33. Precipitation — water falling from clouds, such as rain.
34. Collection — accumulation of water in bodies or surfaces after movement through the cycle.
35. Heating — transfer of energy that can raise temperature or cause change of state.
36. Cooling — loss of thermal energy that can lower temperature or cause change of state.
37. Temperature — measure describing how hot or cold something is.
38. Change of state — physical change from one state of matter to another.
39. Repeated pattern — sequence or relationship that occurs again.
40. Sequence — ordered arrangement of stages or events.

41–60 | Cycle Reasoning and Water Enrichment

41. Metamorphosis — major change in body form during development in some animals.
42. Larva — immature stage in the life cycle of some animals.
43. Pupa — developmental stage between larva and adult in complete metamorphosis.
44. Butterfly — familiar example used to study complete metamorphosis.
45. Frog — familiar example used to compare changing animal life stages.
46. Transpiration — loss of water vapour from plant surfaces; enrichment bridge to later plant Science.
47. Runoff — water flowing over land into waterways.
48. Groundwater — water stored beneath Earth’s surface.
49. Infiltration — movement of water into soil or porous ground.
50. Aquifer — underground layer that stores and transmits groundwater.
51. Surface water — water found on Earth’s surface.
52. Rainfall — precipitation in liquid form.
53. Humidity — amount of water vapour in the air.
54. Water storage — temporary holding of water in part of a larger water system.
55. Water movement — transfer of water between locations or states.
56. Prediction — statement about what is likely to happen based on a pattern or evidence.
57. Observation — information noticed or measured directly.
58. Process — connected series of changes or actions.
59. Condition — circumstance that affects whether or how a process occurs.
60. Rate — how quickly a change occurs.

61–80 | Carbon, Nitrogen and Wider Earth-Cycle Enrichment

61. Carbon dioxide — gas used by plants in photosynthesis.
62. Photosynthesis — process by which green plants use light energy to make food.
63. Respiration — life process involving release of usable energy from food; later-study bridge.
64. Decomposition — breakdown of dead organic matter.
65. Fossil fuel — fuel formed from ancient organic material over geological time.
66. Greenhouse gas — gas that contributes to heat retention in the atmosphere.
67. Combustion — burning reaction that releases energy.
68. Carbon sink — reservoir that stores more carbon than it releases over a period.
69. Carbon storage — retention of carbon in organisms, soil, water or other reservoirs.
70. Global warming — long-term rise in average surface temperature.
71. Nitrogen fixation — conversion of atmospheric nitrogen into forms usable in biological systems.
72. Nitrification — microbial conversion between nitrogen-containing compounds.
73. Denitrification — microbial process returning nitrogen to the atmosphere.
74. Ammonia — nitrogen-containing compound used in later nitrogen-cycle study.
75. Nitrite — nitrogen-containing ion in the nitrogen cycle.
76. Nitrate — nitrogen-containing ion that plants can absorb.
77. Bacteria — microorganisms involved in many decomposition and nutrient-cycle processes.
78. Legume — plant group associated with nitrogen-fixing bacteria in later Science.
79. Atmosphere — layer of gases surrounding Earth.
80. Nutrient cycle — movement and reuse of nutrients through organisms and the environment.

81–100 | Rock, Seasonal and Ecological Enrichment

81. Igneous — rock formed from cooled molten material.
82. Sedimentary — rock formed from accumulated and compacted sediments.
83. Metamorphic — rock changed by heat and pressure.
84. Weathering — breakdown of rock at or near Earth’s surface.
85. Erosion — movement of weathered material by agents such as water or wind.
86. Compaction — pressing together of sediments.
87. Cementation — binding of sediments by minerals.
88. Crystallisation — formation of crystals as material solidifies or comes out of solution.
89. Winter — one season in temperate seasonal cycles.
90. Spring — one season in temperate seasonal cycles.
91. Summer — one season in temperate seasonal cycles.
92. Autumn — one season in temperate seasonal cycles.
93. Equinox — astronomical event when day and night are approximately equal in length.
94. Solstice — astronomical event marking extreme seasonal daylight lengths.
95. Migration — regular movement of animals, sometimes linked to seasonal conditions.
96. Hibernation — extended state of reduced activity in some animals.
97. Food chain — feeding sequence that links organisms and energy transfer.
98. Food web — network of interconnected food chains.
99. Conservation — protection and careful management of organisms and resources.
100. Sustainability — use of resources in ways that preserve future capacity.

Common Cycles Failure Modes

• Diagram dependence: the learner can reproduce one familiar cycle but cannot rebuild it from a new representation.
• Stage/process confusion: a stage such as “pupa” is treated like a process, or a process such as “evaporation” is treated like an object.
• Wrong direction: evaporation and condensation, melting and freezing, or pollination and fertilisation are reversed.
• Missing condition: the answer names a change but not the condition that makes it happen.
• Enrichment overload: carbon or nitrogen cycles are memorised before the Primary life-cycle and water-cycle reasoning is secure.

How to Study Cycles Properly

1. Hide the labels. Ask the student to reconstruct them from the picture.
2. Hide the picture. Ask the student to describe the sequence verbally.
3. Explain every transition. Require a cause, condition or process for each arrow.
4. Change the starting point. A true cycle can be followed from more than one entry point.
5. Change the representation. Move from diagram to table to paragraph and back.
6. Predict a disruption. Ask what happens if one condition or stage is removed.

Where the Other Theme Vocabulary Goes

• Diversity — classification and materials.
• Systems — plant, human and electrical systems.
• Energy — light, heat, photosynthesis and energy conversion.
• Interactions — magnets, forces and environmental relationships.

Science Estate Handoff

Stay here for Cycles vocabulary and reasoning. For the developmental P3–P6 subject map, use How Primary Science Changes from P3 to P6. For tuition/service intent, use Science Tuition at eduKatePunggol.

A cycle is understood when the student can explain the transitions, not merely recite the labels.