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.
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This volume solves one precise learner problem: the learner observes dye spreading faster in warm water and explains it vaguely as heat pushing the colour, or confuses diffusion with currents caused by pouring and uneven heating. 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
A drop of food colouring placed gently into warm water often loses its concentrated boundary sooner than an equal drop in cooler water. The observation is a difference in spreading time, not proof that heat creates more dye.
Temperature describes the thermal condition of the water. In the particle model, warmer water has particles with greater average kinetic motion than cooler water.
Diffusion is the net spreading of particles from a region of higher concentration to regions of lower concentration because particles are moving randomly.
The dye does not decide to move toward empty spaces. Countless random motions and collisions produce an overall spreading pattern from concentrated to less concentrated regions.
Stirring also mixes dye, but by bulk movement caused by a spoon or shaking. A fair diffusion comparison must avoid stirring one beaker more than the other.
Pouring the dye from different heights can create different currents. Equal drop size is not enough if one drop enters with greater speed or at a different depth.
Warm water can also develop convection currents, especially if heating is uneven. Those bulk flows can carry dye and complicate a claim about diffusion alone.
For a classroom comparison, use equal containers, equal water volumes, equal dye drops, matching placement, no stirring and simultaneous timing. Change only the intended temperature.
The relevant measurement should be defined before starting. Time until colour reaches a marked boundary is more precise than saying one beaker “looks mixed.”
Faster spreading does not mean the dye particles become larger, multiply or disappear. The same amount becomes distributed over a larger region.
Given enough time in stable conditions, both beakers may become evenly coloured. Temperature can affect rate without changing the final idea of a uniform mixture.
The reliable routine is identify the observation, distinguish diffusion from bulk flow, compare particle motion, inspect control variables, use a defined timing measure, then state a rate conclusion no stronger than the evidence.
Core decision: At a higher temperature, particles have greater average motion. Dye particles and water particles move and collide more rapidly, so random spreading by diffusion can occur faster, provided the comparison controls stirring, volume, container, dye amount and placement.
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. Describe the observation
State which dye front moved farther or which sample reached uniform colour sooner.
Diagnostic question: What was actually seen or measured? Reliable response: Avoid starting with an invisible-particle claim.
2. Link temperature to motion
Warmer particles have greater average motion than cooler particles.
Diagnostic question: Which setup has higher temperature? Reliable response: State faster average particle motion, not larger particles.
3. Explain net spreading
Random movements carry dye away from the high-concentration drop into less concentrated water.
Diagnostic question: Where is concentration initially highest? Reliable response: Trace spreading without suggesting purposeful motion.
4. Exclude forced mixing
Stirring, shaking, pouring and squeezing can produce bulk motion.
Diagnostic question: Were both samples handled identically? Reliable response: Do not attribute forced movement to diffusion.
5. Inspect convection
Temperature gradients can create circulating water that carries dye.
Diagnostic question: Was each sample at a uniform stable temperature? Reliable response: Acknowledge currents if the pattern shows rising or sinking plumes.
6. Make a rate claim
Shorter time for the same endpoint supports faster spreading under the tested conditions.
Diagnostic question: Was the endpoint defined identically? Reliable response: Do not claim a new substance or more dye.
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: Equal drops
Task. Equal dye drops enter equal volumes of 20°C and 50°C water without stirring. The warm sample becomes uniform sooner.
Reasoning. Temperature is the intended difference, and warmer particles move more rapidly on average. The controlling idea is water temperature while all mixing and observation conditions remain comparable. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. Dye spreads faster in the warmer water under these conditions.
Independent check. Repeat with containers swapped to reduce location effects. 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: Different drop size
Task. Two drops enter warm water while one drop enters cool water.
Reasoning. Dye amount is confounded with temperature. The controlling idea is water temperature while all mixing and observation conditions remain comparable. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. The setup cannot isolate temperature.
Independent check. Use equal measured drops. 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: Stirred warm sample
Task. The warm beaker is stirred but the cool one is not.
Reasoning. Bulk mixing provides an extra cause. The controlling idea is water temperature while all mixing and observation conditions remain comparable. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. No valid diffusion-rate conclusion can be made.
Independent check. Either stir both identically or stir neither. 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: Unequal volumes
Task. The warm beaker contains half as much water.
Reasoning. Distance and dilution conditions differ. The controlling idea is water temperature while all mixing and observation conditions remain comparable. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. The comparison is unfair.
Independent check. Use equal volume and matching container 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 5: Convection plume
Task. Dye rises in looping streams above a heater.
Reasoning. The visible current shows bulk water motion as well as particle diffusion. The controlling idea is water temperature while all mixing and observation conditions remain comparable. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. Describe convection as a possible transport process.
Independent check. Allow water to reach a uniform temperature before adding dye. 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: Same final colour
Task. Both samples eventually become evenly coloured.
Reasoning. Rate can differ even when the eventual distribution is similar. The controlling idea is water temperature while all mixing and observation conditions remain comparable. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. Warm water reached the endpoint sooner; both later became uniform.
Independent check. Compare times, not only final appearance. 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: No extra dye
Task. The warm sample colours a larger region after one minute.
Reasoning. The existing dye is more widely distributed; its amount was not increased. The controlling idea is water temperature while all mixing and observation conditions remain comparable. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. Faster spreading does not create dye.
Independent check. Mass of dye added was equal. 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: Defined endpoint
Task. A grid behind each beaker shows when colour reaches 8 cm from the drop.
Reasoning. The same distance provides an operational measure. The controlling idea is water temperature while all mixing and observation conditions remain comparable. This prevents a learner from choosing an answer merely because one word, number or observation resembles a remembered example.
Answer. Record time to the 8 cm mark for each temperature.
Independent check. Repeat and average comparable trials if taught to do so. 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: Ink on paper
Case. Spreading through paper also depends on absorption and pore structure.
Analysis. Do not transfer a water-only explanation without checking the medium. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Name the additional variable. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 2: Sugar dissolving
Case. Dissolving rate and diffusion are related but not identical questions.
Analysis. Crystal size and stirring can affect dissolving. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Separate the processes. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 3: Perfume in air
Case. Gas particles diffuse through air.
Analysis. Air currents can also carry scent. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Distinguish diffusion from a fan. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 4: Cold sample
Case. Slower spreading does not mean particles stop moving.
Analysis. Cooler particles still move randomly. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. State a rate difference. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 5: Boiling water
Case. Vigorous currents dominate visible mixing.
Analysis. A diffusion-only comparison becomes difficult. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Choose stable non-boiling temperatures. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 6: Uneven heating
Case. A hot bottom and cool top create gradients.
Analysis. Convection may transport dye. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Pre-equilibrate the water. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 7: Different vessels
Case. A tall narrow jar changes travel distances compared with a shallow dish.
Analysis. Container shape is a control variable. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use identical containers. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 8: Different dye concentration
Case. A concentrated drop can appear darker and travel differently.
Analysis. Starting concentration must match. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use one prepared dye solution. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 9: Different placement
Case. A surface drop and a bottom drop face different paths and flows.
Analysis. Position changes the setup. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use a guide for placement. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 10: Delayed timing
Case. Starting one clock late biases the result.
Analysis. Both samples require the same start definition. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Add drops simultaneously or time separately with the same rule. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 11: Visual judgement
Case. “Looks mixed” can vary between observers.
Analysis. A marked endpoint improves repeatability. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Define a colour or distance criterion. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 12: Repeated trials
Case. Variation between drops can occur.
Analysis. Repeats test reliability after fairness is secured. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Record each time, not only the best. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 13: Mass conservation
Case. Spreading changes position, not the amount of dye in a closed beaker.
Analysis. Distribution and quantity are different. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Track where matter goes. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 14: Particle size claim
Case. Heating does not make each dye particle larger in the school particle model.
Analysis. Spacing and motion explain the observation. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Repair the statement. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 15: Purposeful motion
Case. Particles do not seek empty regions.
Analysis. Random motion yields net spreading from high concentration. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Use probability language carefully. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 16: Final equilibrium
Case. Uniform colour means no visible concentration difference, not that particles stop moving.
Analysis. Dynamic motion continues. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Explain the hidden motion. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 17: Cooling after mixing
Case. Cooling can slow further diffusion but does not unmix the colour automatically.
Analysis. Reversing temperature does not reverse distribution. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Predict the observation. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 18: Salt water medium
Case. Different dissolved substances can change density and movement.
Analysis. Medium composition becomes another variable. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Keep water composition equal. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 19: Observation versus explanation
Case. The coloured front is observed; particle motion is the model explaining it.
Analysis. Do not claim particles were individually seen. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Write two separate sentences. State the conclusion in one precise sentence, then add one sentence that names the evidence or relationship that makes it valid.
Deepening case 20: Final audit
Case. Temperature, particle motion, concentration gradient, no forced mixing, fair controls and defined endpoint complete the explanation.
Analysis. Each step blocks a distinct overclaim. Notice that the answer depends on water temperature while all mixing and observation conditions remain comparable; changing a decorative detail would not be enough to change the reasoning.
Challenge. Audit six experimental plans. 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: Heat pushes the dye
What the learner may think. Warmth acts like a hand forcing colour outward.
Why it fails. The particle model explains faster random motion and collisions. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Link temperature to average motion. Use this short test immediately: What moves and how?
Misconception 2: Cold particles do not move
What the learner may think. Only warm-water particles move.
Why it fails. Particles in cool liquid still move, usually more slowly on average. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Compare rates, not motion versus no motion. Use this short test immediately: Does the cool dye eventually spread?
Misconception 3: Spreading creates more dye
What the learner may think. A larger coloured region means greater amount.
Why it fails. The same amount can be distributed more widely. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Separate quantity from concentration. Use this short test immediately: How much dye was added?
Misconception 4: All mixing is diffusion
What the learner may think. Stirring and convection are also called diffusion.
Why it fails. Bulk flows have different mechanisms. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Identify handling and visible currents. Use this short test immediately: Was the water moving as a whole?
Misconception 5: Final colour proves equal rate
What the learner may think. Both beakers end uniform, so rates were equal.
Why it fails. Different paths can reach the same endpoint at different times. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Measure time to a shared endpoint. Use this short test immediately: Which became uniform first?
Misconception 6: One uncontrolled trial proves the rule
What the learner may think. Any warm-cool comparison is enough.
Why it fails. Confounding variables can produce the difference. The error feels efficient because it removes a decision, but it also removes the evidence boundary that makes the answer valid.
Targeted repair. Control volume, vessel, dye and placement. Use this short test immediately: What changed besides temperature?
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. What should be recorded when dye reaches a marked boundary?
Explained answer. The time taken in each sample.
Why this answer earns trust. A shared distance creates a comparable endpoint. Transfer variation: Repeat at another temperature.
Practice 2: Mechanism
Question. Why can dye spread faster at 45°C than 20°C?
Explained answer. Particles have greater average motion at the higher temperature, increasing the rate of random spreading.
Why this answer earns trust. The explanation links temperature to motion and diffusion. Transfer variation: Do not say particles enlarge.
Practice 3: Fair test
Question. Name four controls.
Explained answer. Water volume, container, dye amount and dye placement, with handling and timing also matched.
Why this answer earns trust. These isolate temperature. Transfer variation: Explain one confound.
Practice 4: Stirring
Question. Can a stirred warm beaker be fairly compared with an unstirred cool beaker?
Explained answer. No; the unequal stirring makes the comparison unfair.
Why this answer earns trust. Stirring adds bulk mixing. Transfer variation: Redesign it.
Practice 5: Convection
Question. What do looping dye plumes suggest?
Explained answer. Bulk water currents may be carrying dye.
Why this answer earns trust. The visible pattern is not diffusion alone. Transfer variation: Stabilise temperature.
Practice 6: Quantity
Question. Does faster spreading mean more dye?
Explained answer. No; the same amount can occupy a wider region.
Why this answer earns trust. Distribution changed, not the added amount. Transfer variation: State what became lower locally.
Practice 7: Final state
Question. Both become uniform. Can one still have spread faster?
Explained answer. Yes.
Why this answer earns trust. Rate concerns time to endpoint. Transfer variation: Compare recorded times.
Practice 8: Cold water
Question. Are particles motionless in cool water?
Explained answer. No.
Why this answer earns trust. They still move randomly, generally more slowly on average. Transfer variation: Predict eventual spreading.
Practice 9: Rule recall
Question. State the complete causal chain.
Explained answer. Higher temperature → faster average particle motion → faster diffusion under fair conditions.
Why this answer earns trust. Each arrow names a mechanism. Transfer variation: Recall after two days.
Practice 10: Transfer
Question. Evaluate five experiment diagrams for diffusion and confounds.
Explained answer. Every evaluation separates observation, particle explanation and bulk flow.
Why this answer earns trust. The skill transfers to gases and solutions. Transfer variation: Include one convection case.
Delayed transfer: prove that the learning lasts
Transfer test 1: Fair-test redesign
Repair three flawed warm-cool dye comparisons. 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 revised setup changes only temperature and uses one endpoint. If the criterion is not met, return to the smallest missing decision rather than repeating the entire chapter.
Transfer test 2: Delayed mechanism map
After one week, draw the causal chain from temperature to spreading without notes. 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 map includes particle motion, collisions, concentration and rate. If the criterion is not met, return to the smallest missing decision rather than repeating the entire chapter.
Transfer test 3: Process classification
Sort scenarios into diffusion, stirring, convection or mixed transport. Do this after a delay, without rereading the worked examples. The purpose is to test retrieval and decision-making, not immediate imitation.
Success criterion. Every label cites visible evidence and handling conditions. 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
Use transparent identical cups and one prepared dye mixture. Let the learner define the measurement before adding dye; this makes fair testing more concrete than correcting conclusions afterward.
Ask for two sentences: first the observation, then the particle explanation. Keeping them separate prevents invisible particles from being reported as if directly seen.
If convection appears, treat it as valuable evidence rather than a failed demonstration. Ask how the setup could be changed to isolate diffusion more clearly.
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
Why does dye often spread faster in warm water?
Warmer particles move faster on average, so random spreading can occur more quickly.
Is all visible mixing diffusion?
No. Stirring, pouring and convection can move the water in bulk.
Do particles stop in cold water?
No. They continue moving, generally more slowly on average.
Does a larger coloured region contain more dye?
Not necessarily; the same dye may simply be more widely distributed.
What must be controlled?
Container, water volume, dye amount, placement, handling, timing and endpoint.
Can both samples end the same colour?
Yes. They may reach similar final distribution at different rates.
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.