Primary 3 Science Oral Viva | Materials, Properties & Fair Tests

A child may know the word “waterproof” but still be unable to say which test proves it, which object needs it, or what the same test cannot tell us.

This Primary 3 Science Oral Viva checks whether material-property knowledge is connected rather than memorised. The conversation moves through object, material, property, test, evidence, function and fair comparison. The aim is to hear whether the child can reason without answer choices or a results table doing the thinking for them.

Use the viva after the main materials guides, practicals, Exam Question Map and answer clinics. Ask one question, then one probe. Stop as soon as you find the first weak link and repair that link before continuing.

Wait, What? Knowing the Material Name Is Not the Same as Understanding Suitability

Ask, “Why is this material suitable?” A pupil says “because it is plastic.” That names the material but does not explain the job.

A stronger answer moves through the relationship:

Job → required property → test evidence → suitable material.

Viva Set 1: Object, Material, Property or Use?

Ask: “Is ‘cup’ an object, material, property or use?”

Expected answer: Object.

Follow-up: “What about glass? Transparent? Holding water?”

• glass → material;
• transparent → property;
• holding water → function/use.

Misconception if weak: the child is mixing the language categories before reasoning even begins.

Viva Set 2: Strength

Ask: “What kind of evidence would show that one sample is stronger than another?”

Expected reasoning: Compare how much load similar samples can support before breaking under the test.

Probe: “If a sample feels hard, does that prove it is strongest?”

Strong answer: No. Hardness and strength are not the same test in this P3 context.

Viva Set 3: Flexibility

Ask: “What makes a flexibility test different from a strength test?”

Expected reasoning: Flexibility is about bending without breaking, while strength is about withstanding load.

Probe: “Can one material be strong but not very flexible?”

Expected answer: Yes. They are separate properties.

Viva Set 4: Waterproofness

Ask: “How would you test whether two materials are waterproof?”

Strong reasoning: Use comparable samples, the same amount of water and the same waiting time, then observe whether water is absorbed.

Probe: “If a material floats, does that prove it is waterproof?”

Expected answer: No. Float/sink and waterproofness are different properties.

Viva Set 5: Transparency

Ask: “What observation would support that a material is transparent?”

Expected answer: An object or printed word can be seen clearly through it.

Probe: “Does transparent mean waterproof?”

Expected answer: No. Separate evidence is needed.

Viva Set 6: Float or Sink

Ask: “If Sample A floats and Sample B sinks, what can you say confidently?”

Strong answer: A floated and B sank in the test.

Probe: “Can you conclude A is waterproof? Stronger? Less dense using a formula?”

Expected reasoning: Not from this result alone. The core P3 task is observation and comparison; density calculations are unnecessary.

Viva Set 7: Suitable Material

Ask: “A strap must bend around a bottle. Which property matters most?”

Expected answer: Flexibility.

Probe: “What if the strap also has to hold a heavy load?”

Expected reasoning: Now strength also matters. The required function determines which properties are essential.

Viva Set 8: True but Irrelevant Property

Ask: “A material is strong, waterproof and transparent. The question asks why it is suitable for a window that must allow viewing. Which property should you use?”

Expected answer: Transparency.

Probe: “Are strength and waterproofness false?”

Strong reasoning: No. They may be true, but they are not the direct reason for the stated function.

Viva Set 9: Fair Test

Ask: “Two samples receive different amounts of water in a waterproofness test. What is wrong?”

Expected reasoning: More than the material changed. The comparison is weaker because water amount differs.

Probe: “How would you repair it?”

Expected answer: Use the same amount of water under otherwise similar conditions.

Viva Set 10: Different Thickness

Ask: “Why might very different strip thicknesses weaken a flexibility comparison?”

Strong reasoning: Thickness can affect how far a strip bends, so material type is not the only important difference.

Viva Set 11: Repetition

Ask: “If an unfair test is repeated five times, does it become fair?”

Expected answer: No. Repetition repeats the same design problem.

Probe: “When does repetition help?”

Expected reasoning: After the method is sensible, repetition can increase confidence in the result or reveal inconsistency.

Viva Set 12: No Perfect Option

Give three samples:

• A: transparent + waterproof + rigid;
• B: flexible + waterproof + opaque;
• C: flexible + transparent + absorbs water.

Ask: “Which is fully suitable for a clear, flexible, waterproof cover?”

Expected answer: None.

Diagnostic value: If the child forces a winner, the learner may believe every science question must have one perfect choice.

Viva Set 13: Essential Versus Helpful

Ask: “What is the difference between an essential property and a helpful property?”

Strong answer: Essential means the object cannot perform its main job without it; helpful improves the design but is not required for the stated function.

Viva Set 14: Untested Property

Ask: “A table gives only flexibility and waterproofness results. Can you say which sample is strongest?”

Expected answer: No. Strength was not tested.

Probe: “What should a strong answer say?”

Expected reasoning: Strength cannot be determined from the given evidence.

Viva Set 15: Same Evidence, Different Command

Evidence: Sample A bends farther than B before breaking.

• Ask “describe”: “A bent farther before breaking.”
• Ask “compare”: “A bent farther than B.”
• Ask “infer”: “A is more flexible under the test.”
• Ask “justify use”: “A is more suitable for a bendable strap because it is more flexible.”

This sequence reveals whether the pupil understands both evidence and command words.

Viva Set 16: Stereotype Versus Result

Ask: “You expected a plastic object to float, but it sank. Which answer should you trust?”

Expected answer: The observed result.

Probe: “Why?”

Strong reasoning: Science records what happened in the test instead of replacing it with a stereotype about the material.

The 30-Second Materials Probe

1. “Which property is being tested?”
2. “What result supports that property?”
3. “Why does that property help the object do its job?”

If the child can answer all three without changing properties midway, the relationship is usually secure.

The One-Minute Viva Ladder

1. Name: Identify the property.
2. Evidence: State the matching test result.
3. Function: Explain why the property matters.
4. Fairness: Identify one condition that should stay similar.
5. Limit: State one property the test did not determine.

How to Score the Materials Viva

• Secure: category, property, evidence and function remain consistent across follow-ups.
• Developing: correct property but weak evidence or weak property-function link.
• Fragile: depends on material stereotypes or memorised object examples.
• Needs repair: confuses strength/flexibility, waterproofness/transparency, or object/material/property.

Teacher Use: Change the Surface, Keep the Job

After a correct answer about a rain cover, switch to a window, strap or floating marker. The purpose is to see whether the pupil transfers the property-function relationship instead of memorising “plastic = waterproof”.

Parent Use: Ask for the Test

When a child says “this one is stronger”, ask, “What result would prove that?” When the child says “this one is waterproof”, ask, “What did the water test show?” These short prompts keep the conversation evidence-led.

Viva Challenge Round

1. What test distinguishes strength from flexibility?
2. Can a material be transparent but not waterproof?
3. Can a material be waterproof but opaque?
4. Does floating prove waterproofness?
5. Why is a true property sometimes irrelevant?
6. How do you repair a waterproofness test that used different water amounts?
7. When is “none fully suitable” the best answer?
8. Which property is still unknown after a bending test?

Primary 3 Oral Viva Mastery Check

• I separate object, material, property and function.
• I distinguish strength from flexibility.
• I distinguish waterproofness from transparency.
• I interpret float/sink without importing density calculations.
• I match each test to the correct property.
• I can explain a fairer comparison.
• I connect property to function.
• I recognise true but irrelevant properties.
• I know when no option is fully suitable.
• I do not claim an untested property.

Continue the Primary 3 Science Oral Viva Series

• Living Things, Classification & Evidence
• Life Cycles, Diagrams & Comparisons
• Magnets, Poles & Evidence

Return to the Primary 3 Science Learning Hub.

Source and Syllabus Alignment

This oral diagnostic guide is aligned to the Singapore Ministry of Education Science Teaching & Learning Syllabus: Primary Three to Six, especially P3 diversity of materials and practices including comparing, investigating, measuring, inferring and communicating.