Primary 6 Science Learning Guide | Question Deconstruction, Conditions & Constraints for PSLE

Many Primary 6 Science questions are lost before the Science even begins. The pupil reads quickly, notices a familiar keyword, retrieves a memorised answer and starts writing before identifying what changed, what is measured, which object is being asked about or which condition limits the conclusion.

This guide develops question deconstruction, condition tracking, constraint reading and answer targeting for PSLE Science. It is designed to help pupils rebuild the question before solving it.

Return to the Primary 6 Science Learning Hub.

The deconstruction rule

COMMAND → TARGET → GIVEN FACTS → CHANGED CONDITION → MEASURED OUTCOME → CONSTRAINTS → REQUIRED SCIENCE → ANSWER.

This is an eduKate reasoning routine, not an official SEAB marking formula.

Part I — Read the command before the story

A long setup may contain plants, lamps, wires, containers, temperatures and graphs. The final command may ask for only one variable or one explanation.

Before interpreting the story, identify the job:

• state;
• describe;
• compare;
• explain;
• predict;
• infer;
• suggest;
• evaluate;
• identify a variable;
• justify a conclusion.

The command determines the answer architecture.

Part II — Identify the target object

Many questions contain several objects. A force acts on one object, a substance moves through another and a measurement is taken from a third.

Ask: Which exact object, organism, setup, interval or graph region is the question about?

If the question asks about the car, do not explain the spring unless the spring is needed to explain the car’s motion. If it asks about the leaf, do not answer about the whole plant unless the relationship requires it.

Part III — Separate given facts from inferred facts

Given fact: “Plant A was placed 10 cm from a lamp.”

Given fact: “Plant A produced 42 bubbles in five minutes.”

Inference: “Plant A had a higher measured photosynthesis-related output than Plant B.”

Do not convert an inference into a given fact while reading.

Part IV — Mark the changed condition

Ask what was deliberately changed or what changed naturally in the scenario.

Examples:

• surface type;
• lamp distance;
• number of cells;
• water availability;
• population size;
• load on a spring;
• time interval;
• temperature.

The changed condition is often the centre of the causal explanation.

Part V — Identify the measured outcome

Do not confuse the changed variable with what is measured.

Changed: number of cells.

Measured: fan rotations in ten seconds.

Changed: lamp distance.

Measured: bubble count in five minutes.

Changed: surface type.

Measured: travel distance.

Part VI — Constraints are instructions hidden inside the setup

Common constraints include:

• “all other conditions were kept the same”;
• “during the same time interval”;
• “within the tested range”;
• “assuming no other change”;
• “based only on the graph”;
• “using evidence from the table”;
• “without repeating the experiment”;
• “one difference only”.

These phrases limit what may be claimed.

Part VII — Negative conditions matter

Words such as not, except, least, unchanged, without can reverse the question.

Underline them.

“Which setup does not provide evidence…” is a different job from “Which setup provides evidence…”.

Part VIII — Comparative conditions

When two setups are compared, make a small mental table:

Feature	Setup A	Setup B
Changed condition	10 cm from lamp	30 cm from lamp
Water	same	same
Plant type	same	same
Measured outcome	42 bubbles	20 bubbles

This makes the causal structure visible before explanation begins.

Part IX — Question nesting

One multi-part question may reuse the same setup for different jobs.

Part (a): identify the changed variable.

Part (b): describe the graph trend.

Part (c): explain the trend.

Part (d): suggest one improvement.

Do not repeat the same answer four times. Each part asks for a different operation on the same world.

Part X — Diagram deconstruction

For a diagram:

1. read labels;
2. find arrows;
3. identify what arrows mean;
4. mark open/closed paths;
5. identify measurements;
6. find which part changed;
7. read the command again.

Do not assume every arrow means force or flow.

Part XI — Graph deconstruction

For a graph:

1. read horizontal axis;
2. read vertical axis;
3. check units;
4. identify range;
5. locate the specific region asked;
6. describe pattern before explaining;
7. check whether the question asks interpolation or extrapolation.

Part XII — Table deconstruction

Read row and column headings before numbers.

Ask:

• what quantity does each column contain?
• are units the same?
• are these individual trials or averages?
• are times comparable?
• is there a missing value?
• which rows should actually be compared?

Part XIII — Hidden reference words

Words such as “this”, “it”, “they”, “the result” and “the change” must be resolved.

If the question says “Explain why this happened,” point to the exact preceding result before writing.

Many incomplete answers explain the wrong “this”.

Part XIV — Multi-concept questions

Do not decide the concept from the first keyword.

Example: a question contains a spring, car and rough surface.

Possible Science:

• elastic spring force;
• energy conversion;
• friction;
• fair-test control;
• distance measurement.

The command chooses which one belongs in the answer.

Original case study: spring car

A spring is compressed by the same amount for two trials. The same car is released onto Surface P and Surface Q. The car travels 80 cm on P and 42 cm on Q.

Question: Why does the car travel a shorter distance on Q?

Deconstruction: target = car; changed condition = surface; controlled = spring compression, car; measured outcome = distance; required Science = frictional effect.

Answer: Surface Q produces a greater frictional effect on the car, causing it to slow more quickly and travel a shorter distance before stopping.

Original case study: aquatic plant

A plant is tested at three lamp distances. Bubble counts are measured for five minutes.

Question: State the measured variable.

Do not explain photosynthesis. The answer is simply the number of bubbles produced in five minutes, or the exact measured quantity stated by the setup.

Original case study: food web

A food web shows Bird A eating insects X and Y. X decreases.

Question: Explain why Bird A may not decrease immediately.

Target = Bird A. Changed condition = X decreases. Constraint = food web shows alternative prey Y. Required Science = alternative food source.

Answer: Bird A can still obtain food from Y, so the decrease in X does not necessarily cause an immediate decrease in Bird A.

Part XV — Conditions that cancel out

If a factor is the same in both setups, it usually does not explain the difference.

Gravity acts on both identical cars in the same location. If surface type changes and travel distance changes, gravity is not the factor that explains the difference between the trials.

Part XVI — Question compression

Translate a long question into one short private sentence.

Long story: two cups, different covers, same water volume, same starting temperature, readings after ten minutes.

Private compression: Which cover reduces cooling most?

This reduces working-memory load.

Part XVII — The CONDITIONS checklist

1. C — Command
2. O — Object/target
3. N — Numbers and units
4. D — Difference changed
5. I — Information given
6. T — Time basis
7. I — Intended measurement
8. O — Other controlled conditions
9. N — Negative words / limits
10. S — Science required

This is an eduKate teaching mnemonic.

Part XVIII — Common deconstruction errors

• Answering the topic instead of the command.
• Explaining the wrong object.
• Missing a negative word.
• Ignoring units.
• Comparing different time intervals.
• Using a factor that did not change.
• Assuming a graph shows cause when it shows only relationship.
• Writing beyond the stated range.
• Forgetting an alternative food source or branch.
• Using prior knowledge to override explicit question conditions.

Part XIX — Ten-second exam routine

Before writing:

1. Circle command.
2. Underline target.
3. Box changed condition.
4. Mark measured outcome.
5. Notice same-time / same-start / no-other-change constraints.
6. Choose one primary Science relationship.

Then answer.

Where to connect

• Integrated Multi-Concept Reasoning & Unfamiliar PSLE Setups
• Scientific Vocabulary, Precision & Answer Language
• Primary 5 Question Deconstruction, Conditions & Constraints

Retrieval checklist

• I identify the command before the topic.
• I identify the exact target object or setup.
• I separate given facts from inferences.
• I identify changed and measured variables.
• I notice constraints such as same time and tested range.
• I resolve pronouns such as “this” and “it”.
• I compare only the relevant rows or setups.
• I choose Science after reconstructing the question.
• I can compress a long setup into one private sentence.
• I answer the requested job and stop.

The quiet return

Question reading is not separate from Science. It is the doorway into the scientific model. When the pupil reconstructs the command, target, changed condition, measurement and constraints correctly, the correct concept becomes easier to retrieve.

Read the job. Find the target. Mark the change. Respect the conditions. Then choose the Science.

Return to the Primary 6 Science Learning Hub.