Series route: This guide belongs to the complete PSLE Learner’s Guide volume directory. The original PSLE Learning Guide supplies the wider English, Mathematics and Science route, while PSLE Science provide verified subject-specific continuation.
Find your route through this guide
This volume solves one precise learner problem: the learner sees the water level fall beside a plant and concludes that every missing drop entered the roots, without considering evaporation from the exposed water or another pathway. The aim is not to memorise a slogan. It is to understand the mechanism well enough to recognise the idea when the wording, numbers, diagram or context changes. A Primary 6 learner should be able to explain the decision, perform it under time pressure, and detect a tempting answer that only looks familiar.
- Understand the mechanism before memorising a form.
- Study the worked examples and compare near-misses.
- Repair common misconceptions with targeted tests.
- Complete graded independent practice before reading the answers.
- Use delayed transfer and examination control to make the skill durable.
- Use the parent and tutor notes only after the learner has attempted the work.
The problem beneath the mistake
Observation and explanation are different jobs. “The water level fell” is an observation. “The roots absorbed all the missing water” is a causal explanation that needs a comparison.
Water can leave an open container by evaporation. A plant can also absorb water through its roots, and some absorbed water may later be lost from leaves. The final level alone does not show how much followed each pathway.
A useful control uses the same container and starting water level under the same surroundings but without the plant. Its level change estimates the loss that can occur without root absorption.
The experimental setup may also cover the water surface, for example with an appropriate oil layer in a supervised classroom investigation, to reduce direct evaporation. The conclusion must match the actual design rather than a remembered diagram.
The strongest PSLE explanation names the observation, identifies the alternative cause, describes the comparison and states only the conclusion the evidence supports.
Core decision: A falling water level shows that water left the measured container region; to attribute the change to root absorption, compare with a suitable no-plant control that experiences the same evaporation conditions.
A useful rule has three parts: a trigger, an operation and a check. The trigger tells you when the rule applies. The operation tells you what to do. The check tells you whether the result still matches the meaning of the question. Learners who remember only the operation often apply it in the wrong place; learners who remember only an example often freeze when the surface details change.
Mechanism: why the rule works
1. State the observation
Record the measured change without adding a cause.
Diagnostic question: What was directly seen or measured? Reliable response: Write “water level decreased by…”
2. List plausible pathways
Consider root absorption, evaporation, leakage or measurement error where relevant.
Diagnostic question: Could the change occur without the plant? Reliable response: Name at least one alternative.
3. Choose one tested factor
The investigation should compare presence versus absence of the plant or another single factor.
Diagnostic question: What differs between setups? Reliable response: State the independent variable.
4. Match the control
Keep container, exposed surface, starting level, duration and surroundings comparable.
Diagnostic question: Would evaporation affect both similarly? Reliable response: Align conditions.
5. Compare changes
The difference between plant and control may be associated with the plant under the stated conditions.
Diagnostic question: How much extra decrease occurred? Reliable response: Subtract comparable changes carefully.
6. Limit the conclusion
Evidence may support contribution, not prove that every missing drop was absorbed.
Diagnostic question: Does the wording exceed the design? Reliable response: Use “supports” and name conditions.
Worked examples: make the decision visible
Do not race through these examples. Before reading each explanation, name the evidence that matters and the information that does not. Then compare the correct route with the tempting route. That comparison is where the transferable learning sits.
Worked example 1: No control
Task. A beaker with a plant loses 12 mL in a day.
Reasoning. Evaporation could account for some loss. The controlling idea is whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. The result alone does not determine how much roots absorbed.
Independent check. Ask what happens without plant. A good check approaches the conclusion from a different direction. Repeating the same steps more slowly may repeat the same hidden assumption.
Worked example 2: Matched control
Task. Plant beaker loses 12 mL; no-plant beaker loses 3 mL.
Reasoning. If other conditions are alike, 3 mL represents background loss and the extra 9 mL is associated with the plant setup. The controlling idea is whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. The comparison supports root uptake contributing to the larger decrease.
Independent check. Do not claim perfect measurement. A good check approaches the conclusion from a different direction. Repeating the same steps more slowly may repeat the same hidden assumption.
Worked example 3: Different surface area
Task. Control beaker is wider than plant beaker.
Reasoning. Different exposed surface can change evaporation. The controlling idea is whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. The control is not well matched.
Independent check. Use identical containers. A good check approaches the conclusion from a different direction. Repeating the same steps more slowly may repeat the same hidden assumption.
Worked example 4: Different locations
Task. One setup is in sunlight and one in shade.
Reasoning. Temperature and light can change water loss. The controlling idea is whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. The plant effect is confounded.
Independent check. Place together under comparable conditions. A good check approaches the conclusion from a different direction. Repeating the same steps more slowly may repeat the same hidden assumption.
Worked example 5: Covered surface
Task. Both water surfaces are similarly covered while stems pass through appropriate openings.
Reasoning. Direct evaporation is reduced in both setups. The controlling idea is whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. A difference more specifically reflects the plant pathway, within limits.
Independent check. Check seals are comparable. A good check approaches the conclusion from a different direction. Repeating the same steps more slowly may repeat the same hidden assumption.
Worked example 6: Leak
Task. A container has a crack.
Reasoning. Water can leave without evaporation or absorption. The controlling idea is whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. Repair or replace the apparatus before interpreting.
Independent check. Inspect setup. A good check approaches the conclusion from a different direction. Repeating the same steps more slowly may repeat the same hidden assumption.
Worked example 7: Marks not volume
Task. Water level falls in two differently shaped containers.
Reasoning. Equal height changes need not equal equal volumes. The controlling idea is whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. Use identical containers or measure volume directly.
Independent check. Check geometry. A good check approaches the conclusion from a different direction. Repeating the same steps more slowly may repeat the same hidden assumption.
Worked example 8: Repeated trials
Task. Several matched pairs show similar differences.
Reasoning. Replication tests whether the pattern is dependable. The controlling idea is whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. Confidence increases, but the design limits remain.
Independent check. Look for outliers and consistency. A good check approaches the conclusion from a different direction. Repeating the same steps more slowly may repeat the same hidden assumption.
Deepening lab: compare cases, conditions and limits
A method becomes independent when you can say where it applies, where it stops and which change would alter the conclusion. The cases below deliberately vary one structural feature at a time. For each case, pause before the analysis and predict whether the core rule remains available. Then name the exact condition that controls the decision. This is harder than repeating a worked solution, but it is also closer to what an unfamiliar examination item demands.
Deepening case 1: Large leaf area
Case. A plant has more leaves.
Analysis. It may lose more water through transpiration, but root uptake and leaf loss form a chain. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Keep species and size controlled when testing another factor. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 2: Wilted plant
Case. A damaged plant may absorb or lose water differently.
Analysis. Health is a relevant condition. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use comparable specimens. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 3: Airflow
Case. A fan affects one setup.
Analysis. Moving air can alter evaporation and transpiration. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Keep airflow alike. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 4: Temperature
Case. One container is warmer.
Analysis. Temperature changes evaporation rate. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Measure or control it. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 5: Humidity
Case. Surrounding moisture differs.
Analysis. Humidity can affect water loss. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use the same location. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 6: Starting level
Case. Setups begin with different volumes.
Analysis. Absolute change may not be comparable. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Standardise starting conditions. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 7: Duration
Case. One is measured after six hours and another after twelve.
Analysis. Time exposure differs. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use equal intervals. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 8: Root size
Case. Plants have very different root systems.
Analysis. Capacity for uptake may differ. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Match size or record it. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 9: Oil layer
Case. A thin layer can reduce evaporation from water surface in a supervised setup.
Analysis. It must be applied consistently and safely. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Explain its experimental job. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 10: Plastic cover
Case. A cover changes humidity around leaves as well as water surface.
Analysis. A control feature can introduce another change. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Define the boundary carefully. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 11: Condensation
Case. Droplets form inside a cover.
Analysis. Water may have changed location rather than left the whole system. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Track all reservoirs. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 12: Mass measurement
Case. Weighing the whole setup can complement level readings.
Analysis. Mass tracks total loss from the system more directly. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Keep instruments calibrated. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 13: Dye
Case. Coloured water appears in a stem.
Analysis. It traces movement but may not represent every natural condition. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use as qualitative evidence. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 14: Cut stem
Case. A shoot without roots changes the tested pathway.
Analysis. It is not a direct root-absorption comparison. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. State what is actually present. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 15: Two species
Case. Different species lose different amounts.
Analysis. Species becomes another variable. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Do not attribute difference only to light. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 16: Measurement reading
Case. Eye position differs at each reading.
Analysis. Parallax can create apparent level change. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Read at eye level. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 17: Meniscus
Case. The curved water surface is read inconsistently.
Analysis. Reference point must be fixed. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use the same meniscus rule. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 18: Negative control
Case. No plant shows background loss.
Analysis. It does not prove zero evaporation in the plant setup, but estimates it under matched conditions. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use cautious subtraction. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 19: Positive comparison
Case. A known active plant setup can test whether apparatus detects change.
Analysis. Controls answer different questions. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Name the control purpose. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 20: Full explanation
Case. Observation, alternative, control, comparison and limitation form one chain.
Analysis. Leaving out the alternative weakens causal reasoning. Notice that the answer depends on whether the comparison isolates the presence of the plant while keeping container, water surface, time, temperature, airflow and other relevant conditions alike; changing a decorative detail would not be enough to change the reasoning.
Challenge. Write the chain in five sentences. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Finish the lab with a blank-page recall. Write the rule, its conditions, one confirming example, one near-miss and one independent check from memory. Compare that page with the article only after finishing. If the rule is correct but the condition is missing, the learning is not yet safe: an overgeneralised rule can produce confident errors. If the condition is correct but no example can be generated, practise construction rather than rereading.
Common misconceptions and targeted repairs
Misconception 1: All missing water entered roots
What the learner may think. A lower level is complete proof of absorption.
Why it fails. Open water can evaporate and apparatus can leak. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Use a matched no-plant control. Use this short test immediately: Could the level fall without roots?
Misconception 2: Control means no change
What the learner may think. The control water level must stay fixed.
Why it fails. A control records background change. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Compare its decrease with the plant setup. Use this short test immediately: What process still operates?
Misconception 3: Any empty beaker works
What the learner may think. Container shape and location do not matter.
Why it fails. They affect evaporation and measurement. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Match relevant conditions. Use this short test immediately: What else differs?
Misconception 4: Difference equals exact absorption
What the learner may think. Subtracting control loss gives a perfect value.
Why it fails. Natural variability and measurement limits remain. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Report the supported estimate under conditions. Use this short test immediately: How precise is the method?
Misconception 5: More water loss means healthier plant
What the learner may think. A larger decrease always proves better growth.
Why it fails. Loss can reflect heat, damage or high transpiration. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Measure growth separately. Use this short test immediately: What was actually measured?
Misconception 6: Repeated readings fix bad design
What the learner may think. Many trials remove confounding variables.
Why it fails. Replication cannot repair a systematic mismatch. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Correct design first, then repeat. Use this short test immediately: Is the comparison fair?
Graded independent practice
Attempt each item without looking ahead. Write one line that identifies the controlling evidence before writing the final answer. Items 1–3 check recognition, 4–7 require explanation, and the later items change the surface form so that memory alone is insufficient.
Practice 1: Observation
Question. Rewrite “The plant drank 10 mL” as an observation.
Explained answer. The measured water volume decreased by 10 mL.
Why this answer earns trust. Cause is removed from the direct record. Transfer variation: Add a separate hypothesis.
Practice 2: Alternative
Question. Name one non-root cause of falling level.
Explained answer. Evaporation from the water surface.
Why this answer earns trust. It can occur without a plant. Transfer variation: Name another possible apparatus cause.
Practice 3: Control
Question. Describe a basic control.
Explained answer. An identical container with the same starting water and conditions but no plant.
Why this answer earns trust. Only plant presence differs. Transfer variation: State matched variables.
Practice 4: Comparison
Question. Plant loses 15 mL; control loses 4 mL. What can be said?
Explained answer. The extra 11 mL decrease is associated with the plant setup if conditions are matched.
Why this answer earns trust. Background loss is considered. Transfer variation: Use cautious language.
Practice 5: Faulty design
Question. Why is a wide control beaker unsuitable beside a narrow plant tube?
Explained answer. Different exposed surface areas can change evaporation.
Why this answer earns trust. More than one factor differs. Transfer variation: Repair with identical containers.
Practice 6: Cover
Question. Why cover both water surfaces similarly?
Explained answer. To reduce and equalise direct evaporation while keeping treatment fair.
Why this answer earns trust. The control feature has a stated job. Transfer variation: Check leaf environment is not changed unintentionally.
Practice 7: Reading error
Question. How can parallax be reduced?
Explained answer. Read the same scale at eye level from the same reference point.
Why this answer earns trust. Measurement procedure is standardised. Transfer variation: Repeat readings.
Practice 8: Conclusion
Question. Can the experiment prove every absorbed drop later left through leaves?
Explained answer. No; that requires additional evidence about the later pathway.
Why this answer earns trust. Conclusion stays within design. Transfer variation: Propose a new measurement.
Practice 9: Rule recall
Question. State the causal rule.
Explained answer. A falling level alone does not prove root absorption; compare with a matched no-plant control for background loss.
Why this answer earns trust. Observation and cause are separated. Transfer variation: Recall later.
Practice 10: Transfer
Question. Design three matched pairs testing plant presence, leaf area and airflow separately.
Explained answer. Each pair changes one factor and names its control.
Why this answer earns trust. Fair-test reasoning transfers. Transfer variation: Predict and then measure.
Delayed transfer: prove that the learning lasts
Transfer test 1: Control audit
Inspect ten plant-water diagrams and list every uncontrolled difference. Do this after a delay, without rereading the worked examples. The purpose is to test retrieval and decision-making, not immediate imitation.
Success criterion. Each criticism names how it could affect water loss. If the criterion is not met, return to the smallest missing decision rather than repeating the entire chapter.
Transfer test 2: Evidence ladder
Sort claims into observation, supported inference and unsupported certainty. Do this after a delay, without rereading the worked examples. The purpose is to test retrieval and decision-making, not immediate imitation.
Success criterion. Wording matches evidence strength. If the criterion is not met, return to the smallest missing decision rather than repeating the entire chapter.
Transfer test 3: Delayed design
After a week, design a fair comparison without a model diagram. Do this after a delay, without rereading the worked examples. The purpose is to test retrieval and decision-making, not immediate imitation.
Success criterion. The control estimates background evaporation and the conclusion is limited. If the criterion is not met, return to the smallest missing decision rather than repeating the entire chapter.
Examination control
1. Read the job before the story. Underline the command and the noun it governs. “Explain the change,” “state the word,” “find the fraction” and “identify the evidence” are different jobs even when the surrounding context is similar.
2. Separate given information from remembered information. Use only the facts supplied for the current task plus secure subject knowledge. Do not let a previous question, a familiar worksheet or an expected pattern silently become new evidence.
3. Write enough working to expose the decision. A marker or teacher should be able to see the relationship that justifies the answer. Extra sentences are not automatically stronger; the strongest working is concise, relevant and checkable.
4. Reserve a different-route check. For language, read the sentence for meaning and grammar. For mathematics, estimate or reverse the operation. For science, check the claim against the stated observation and a conservation or fair-test principle.
5. Stop when the requested job is complete. Unrequested speculation can contradict a correct answer. Add detail only when it explains the mechanism or satisfies another explicit part of the question.
Under time pressure, use a compact four-part margin routine: trigger → evidence → operation → check. Trigger names the feature that activates the method. Evidence identifies the exact words, values or observations allowed. Operation performs the language, mathematical or scientific step. Check asks whether the final statement answers the requested job, preserves units or referents, and avoids a stronger claim than the evidence supports.
A compact error log
After practice, do not record only “careless mistake.” Name the broken decision. Useful labels include trigger missed, evidence imported, relationship reversed, referent lost, unit dropped, operation correct but job wrong, and check repeated the same route. Add one prevention cue beside the label. A short accurate log is more useful than a long emotional account because it tells the learner what to do on the next item.
Review the log after two days and again after a week. Reattempt only one or two representative items first. If the method transfers, move to a mixed set. If it fails, repair the exact link between trigger and operation. This spacing matters because a solution can feel obvious while it is still visible and disappear when the page is closed.
Notes for parents and tutors
Begin with “What did you directly observe?” before asking why the change occurred.
Use safe, teacher-supervised classroom investigations; do not ask children to handle oils, glassware or damaged equipment alone.
Reward cautious causal language when the design supports contribution but not complete proof.
The adult’s most useful question is not “Why were you careless?” but “Which decision did the evidence require?” Ask the learner to point to the controlling word, value, relationship or observation. If the learner can explain that link, reduce support. If the learner cannot, model one example and then change the surface details for the next attempt.
Frequently asked questions
Does a falling water level prove roots absorbed water?
Not by itself, because evaporation or another pathway may also lower the level.
What is the basic control?
A matched no-plant setup under the same relevant conditions.
Why might the control level also fall?
Water can evaporate even without a plant.
Can I subtract the control loss?
It can give an estimate of the extra decrease associated with the plant if the setups are well matched.
What must stay the same?
Container, starting level, exposed surface, duration, temperature, airflow and other relevant conditions.
What is the best exam sentence?
The no-plant control estimates water loss by evaporation, so the extra decrease in the plant setup supports root absorption contributing to the change.
Next routes
Return to the complete volume directory to locate the series, use the original PSLE Learning Guide for the foundation route, and continue through PSLE Science for verified subject guidance. The next useful task is a mixed set in which this idea is sometimes relevant and sometimes irrelevant; that is the point at which a learner must choose, not merely copy.