Primary 5 Science Materials Quiz

Primary 5 Science Quiz - Materials - Answer Key

Section A: Multiple Choice (1 mark each)

1) B A solid has a fixed volume. It does not take the shape of its container (A), cannot be easily compressed (C), and its particles vibrate in fixed positions rather than moving freely (D).

2) C Thermal conductivity is the property that allows heat to pass through a material easily. Metal is a good thermal conductor, while plastic is a poor thermal conductor (insulator).

3) B Glass is transparent, which allows light to pass through, making it suitable for a window pane. Wood, rubber, and ceramic are opaque.

4) C Evaporation is the process by which water changes from a liquid to a gas at temperatures below boiling point. The water in the puddle evaporated into the atmosphere.

5) D An iron nail is made of metal, which is a good conductor of electricity. Rubber, wood, and plastic are insulators (poor conductors of electricity).

Section B: Short Answer (2 marks each)

6)

• In a solid, particles are closely packed in a fixed, regular arrangement, while in a liquid, particles are slightly further apart in a random arrangement. [1]
• In a solid, particles can only vibrate in their fixed positions, while in a liquid, particles can slide past one another and move freely within the liquid. [1]

Common mistake: Students may say "solids have more particles than liquids" — this is incorrect; the number of particles depends on mass, not state of matter.

7) Cotton fabric is more suitable for making a bath towel. [1] Cotton is more absorbent (allows water to pass through and be trapped within its fibres) compared to polyester, which repels water. A bath towel needs to absorb water from the body to dry a person effectively. [1]

8) The temperature of the ice cube remains constant at 0°C while it is melting. [1] The heat energy absorbed is used to overcome the forces of attraction between the particles, causing them to break out of their fixed arrangement and move further apart, changing from a solid to a liquid. [1]

9) The metal loses its property of being resistant to corrosion / its appearance changes (it becomes rusty and loses its shine / it becomes weaker). [1] To prevent rusting, paint the metal gate / apply a coat of oil or grease / galvanise the metal with a layer of zinc. [1]

10) She should use a cardboard box filled with styrofoam pieces. [1] Styrofoam is a poor conductor of heat and is soft/cushioning, which absorbs impact and protects the fragile glass vase from breaking during delivery. A thin plastic bag does not provide cushioning or protection from impact. [1]

11) A ceramic mug is a poor conductor of heat (heat insulator), so it does not transfer heat quickly to the hand holding it, making it safe to hold hot drinks. [1] A metal cup is a good conductor of heat, so it would become too hot to hold if a hot drink is poured into it. [1]

12) Any one difference for [1], explanation for [1]. Examples:

• Evaporation occurs at any temperature, while boiling occurs only at a specific temperature (boiling point).
• Evaporation occurs only at the surface of the liquid, while boiling occurs throughout the liquid.
• Evaporation is a slow process, while boiling is a rapid process.

13) The property is brittleness (or toughness/hardness). [1] Glass is brittle, meaning it breaks or shatters easily upon impact. Gold is tough/malleable, meaning it can be dented or deformed without breaking. [1]

14) The volume of the gas increases when it is transferred to a larger container. [1] This is because gas particles are far apart and move freely in all directions; they will spread out to fill the entire space of the larger container, taking the shape and volume of the new container. [1]

15) Material X. [1] A rigid, waterproof water bottle needs to be strong (not flexible, so it holds its shape), waterproof (so it does not leak), and strong (so it does not break easily). Material X is not flexible (rigid), waterproof, and strong. [1]

Section C: Open-Ended / Application (3 marks each)

16) (a) The open beaker will have less water (or no water), while the closed beaker will still have 200 ml of water. [1] (b) In the open beaker, the water evaporates into the surrounding air as water vapour. Since the beaker is open, the water vapour escapes and the water level decreases. Over a week, most or all of the water evaporates. [1] In the closed beaker, evaporation still occurs, but the water vapour cannot escape. It condenses on the lid and drips back into the beaker, so the total amount of water remains the same. [1]

17) (a) Advantage of Material A (wood): Wood is a poor conductor of heat, so it will not get too hot under the sun and will be comfortable to touch. / Wood does not rust. [1] (b) Advantage of Material B (stainless steel): Stainless steel is strong and durable, so it will not break or rot easily. / Stainless steel is smooth, allowing children to slide down easily. [1] (c) Recommend Material B (stainless steel) because it is waterproof, strong, and does not rot or rust when left outdoors in the rain, whereas wood may rot or warp when exposed to rain and sun over time. [1] (Also accept Material A with valid reasoning about heat safety).

18) (a) The wet cloth will become dry. [1] (b) The hot water in the basin heats the air inside the glass bottle. The air inside the bottle expands and moves out of the bottle, carrying water vapour from the wet cloth away with it. [1] The increased temperature also speeds up the rate of evaporation of the water from the wet cloth into the surrounding air, causing the cloth to dry. [1]

19) (a) Ravi should attach a wax ball to one end of each rod. He should place the other end of each rod into the pot of boiling water at the same time, ensuring the rods are made of the same material and only differ in thickness. [1] (b) He should measure the time taken for the wax ball on each rod to melt and drop off. [1] (c) If the thicker rod conducts heat better, the wax ball on the thicker rod will melt and drop off faster than the wax ball on the thinner rod. [1]

20) (a) The volume of the gas decreases. [1] (b) The distance between the gas particles decreases (they are pushed closer together). [1] (c) Gas particles are far apart and can be compressed, allowing the piston to be pushed inwards. In a solid or liquid, the particles are already closely packed together with very little space between them, so they cannot be compressed. [1]