Primary 3 Science Materials Quiz

Primary 3 Science Quiz - Materials: Answer Key

Total Marks: 40

Teaching note for students: Materials have properties such as strength, flexibility, ability to float or sink, whether they absorb water (waterproof or not), and how much light they let pass through. We choose a material for a job by matching its properties to what the object must do.

Answer 1.

(2) Plastic sheet — 1 mark. An umbrella cover must be waterproof: it must not let rainwater soak through. Plastic does not absorb water. Newspaper, cotton towel, and cardboard all soak up water, so the rain would come through. Common mistake: choosing cotton because it feels "cloth-like" — cloth towels absorb water, which is why we use them to dry things.

Answer 2.

(3) Glass — 1 mark. A window must let most light pass through so Mei can see her toys inside. Wood, metal, and ceramic do not allow light to pass through, so she could not see anything.

Answer 3.

(2) Rubber band — 1 mark. Flexible means a material can bend or stretch without breaking. A rubber band stretches and springs back. Ceramic, glass, and wood are stiff — they hold their shape and may crack or snap if bent.

Answer 4.

(4) Wooden block — 1 mark. Some materials float (stay on or near the water surface) and some sink. The wooden block floated; the metal spoon, glass marble, and coin sank to the bottom. Teaching note: "Float" means the object stays on top of the water, not just touching the water.

Answer 5.

(2) Plastic and wood do not get hot as quickly as metal — 1 mark. Metal lets heat travel through it quickly, so a metal handle would become too hot to hold. Plastic and wood slow heat down, keeping the handle cooler and safer. Common mistake: choosing (3) — the reason is about heat, not weight.

Answer 6.

(3) Rubber — 1 mark. Check each clue: it lets NO light pass (so not glass), it bends easily (so not ceramic, which is stiff), and it does not absorb water (so not wood, which soaks up water). Only rubber matches all three clues. Marking tip: students should eliminate options clue by clue.

Answer 7.

**(1) It is strong and does not break easily under heavy loads — 1 mark.

<stage5_quiz_answers_md>

Primary 3 Science Quiz - Materials: Answer Key

Total Marks: 40

Teaching note: Materials have properties such as strength, flexibility, floating or sinking, absorbing water (waterproof or not), and how much light they let pass through. We choose a material by matching its properties to what the object must do.

Answer 1.

(2) Plastic sheet — 1 mark. An umbrella cover must be waterproof. Plastic does not absorb water. Newspaper, cotton towel, and cardboard soak up water, so rain would come through. Common mistake: choosing cotton because it feels cloth-like — cloth absorbs water, which is why we use towels to dry things.

Answer 2.

(3) Glass — 1 mark. A window must let light pass through so Mei can see her toys inside. Wood, metal, and ceramic do not allow light through.

Answer 3.

(2) Rubber band — 1 mark. Flexible means a material can bend or stretch without breaking. Ceramic, glass, and wood are stiff and may crack if bent.

Answer 4.

(4) Wooden block — 1 mark. The wooden block floated; the metal spoon, glass marble, and coin sank. Teaching note: "Float" means staying on top of the water surface.

Answer 5.

(2) Plastic and wood do not get hot as quickly as metal — 1 mark. Metal lets heat travel through it quickly, so a metal handle would become too hot to hold. Common mistake: choosing (3) — the reason is about heat, not weight.

Answer 6.

(3) Rubber — 1 mark. Check each clue: no light passes (not glass), bends easily (not ceramic), does not absorb water (not wood). Only rubber matches all three clues. Marking tip: eliminate options clue by clue.

Answer 7.

(1) It is strong and does not break easily under heavy loads — 1 mark. Bridges carry heavy cars and people, so the material must be strong. Metal being "soft," absorbing water, or bending very easily would make bridges unsafe.

Answer 8.

(2) Plastic — 1 mark. Plastic is waterproof (water stays on top) and light, so it carries the wet costume without soaking or tearing. Paper and cardboard absorb water; wood is heavy.

Answer 9.

(2) glass, plastic, ceramic — 1 mark. These are made in factories by people. Wood, cotton, wool, rubber, leather, silk, and sand come from plants, animals, or the ground (natural).

Answer 10.

(1) To make the test fair — 1 mark. Equal-sized pieces mean each material gets the same chance to absorb water, so only the material's property changes the result.

Answer 11.

(a) Glass allows light to pass through, so we can see out of the window. (1 mark) (b) Glass is waterproof — it does not absorb water, so rain cannot come in. (Also accept: it is stiff/hard and keeps its shape.) (1 mark)

Answer 12.

Corrected table (the given example tick was wrong — plastic is man-made):

(1 mark per correct row; 2 marks total.) Wood and cotton come from plants; plastic and glass are made in factories.

Answer 13.

(a) Flexible (elastic) — rubber stretches when pulled and returns to its original shape. (1 mark) (b) Any one: hair tie/elastic band, trouser waistband, bungee cord, slingshot, elastic strap of a bag. (1 mark)

Answer 14.

Disagree. Some materials are strong but light. Example: plastic — a plastic bag or bottle is light but strong and does not tear/break easily. (Also accept aluminium foil: thin and light but strong.) (2 marks: opinion + supporting example)

Answer 15.

(a) A (paper towel) and C (cotton cloth) — water soaked into them. (1 mark) (b) Choose B or D (either accepted). Reason: the drop stayed on top, so the material does not absorb water (is waterproof) and will keep the lunch box dry. (1 mark)

Answer 16.

(a) He should count the number of coins added until the strip breaks or bends down a lot. The strip that holds the most coins is the strongest. (1 mark) (b) Any TWO kept the same: distance between the supports (10 cm); size and thickness of each strip; same paper cup; same type of coins; cup hung at the middle of the strip. (2 marks) (c) Thin metal is the strongest because it held 50 coins before breaking, more than plastic (20 coins) and paper (5 coins). (1 mark)

Answer 17.

Choice: Rubber tiles. (1 mark) Reason 1: Rubber is flexible and soft, so it cushions falls and children get hurt less if they trip. (1–2 marks) Reason 2: Rubber does not break easily under impact; ceramic is hard and brittle — it cracks or shatters, and sharp pieces can cut children. (1–2 marks) Total: 4 marks (choice + two reasons using properties).

Answer 18.

(a) Sheet A (clear plastic) — the apple was seen completely and clearly, so it lets the most light pass through. (1 mark) (b) Sheet B (frosted plastic). It still lets some light through (so the bathroom is not dark), but the image seen through it is blurry, so people outside cannot see clearly inside. (2 marks) (c) Sheet C (brown cardboard) — no light passed through, so it protects the book from light best. (1 mark)

Answer 19.

(a) Wood. (1 mark) (b) Reason 1: Wood floats on water, but metal sinks, so a wooden boat stays on the surface. (1–2 marks) Reason 2: Wood is light and easy to shape into a boat; (also accept: metal may rust after time in water). (1–2 marks) Total: 3 marks.

Answer 20.

Recommendation: Reusable containers that customers bring back and wash. (1 mark) Reasons (any two, using properties):

• Reusable containers are strong and durable, so they can be washed and used many times instead of being thrown away after one use.
• This creates much less rubbish/waste than plastic takeaway containers or paper boxes, which are used once and discarded.
• Over time it also saves money because Uncle Tan does not keep buying new containers. (3 marks for comparison/reasons.)

END OF ANSWER KEY