Question 1

Sarah found a plant in the garden and measured its height. After two weeks, she measured its height again. From her observation, Sarah concluded that the plant is a living thing because it can ____.

Accepted Answer

A. grow. The only observation Sarah made was a change in height over two weeks, which shows the plant has grown. She did not observe breathing, reproduction, or responses to stimuli.

Question 2

The diagram below shows a young plant. The leaf helps the plant to ____.

Accepted Answer

A. make food. Leaves carry out photosynthesis to make food for the plant. The stem keeps it upright, while the roots absorb water and nutrients.

Question 3

Which of the following shows the correct order when food moves through some parts of the digestive system?

Accepted Answer

B. stomach → small intestine → large intestine. After being swallowed, food enters the stomach, then passes into the small intestine where digested nutrients are absorbed, then to the large intestine where water is absorbed.

Question 4

The diagram shows the life cycle of a plant. What is the stage marked X?

Accepted Answer

B. seed. A plant's life cycle goes from seed → young plant → adult plant → seed. Stage X is between the adult plant and the young plant, so it is the seed.

Question 5

The diagram shows a painting hung on a wall using an iron nail. Iron is used to make nails because iron ____.

Accepted Answer

B. is strong. A nail must support the weight of the painting without bending or breaking, so the relevant property of iron is that it is strong.

Question 6

An object A was attracted to a magnet, as shown in the figure below. Object A is made of ____.

Accepted Answer

A. steel. Only magnetic materials are attracted to magnets. Of the options given, only steel (which contains iron) is a magnetic material.

Question 7

Which of the following properties is true for both air and a pencil?

Accepted Answer

B. They take up space.. All matter takes up space. Air cannot be seen, has no fixed shape and no fixed volume, while a pencil has fixed shape and volume — the only property common to both is that they take up space.

Question 8

Jayden set up an experiment as shown below. First, he cut a star out of a square cardboard. He then placed the cardboard in a straight row. A torch was shone at them. Which of the following would Jayden see on the screen?

Accepted Answer

C. A dark square with a bright star-shaped patch of light in the middle.. The opaque cardboard blocks light and casts a dark square shadow on the screen, but the star-shaped hole lets light through, producing a bright star-shaped patch of light inside the dark square.

Question 9

Jane wants to measure the temperature of water in a beaker. Which of the following diagrams shows the correct position of the thermometer when taking the temperature reading?

Accepted Answer

D. Thermometer held upright with bulb fully submerged in the middle of the water, not touching the sides or bottom.. To get an accurate reading of the water's temperature, the thermometer bulb must be fully immersed in the water without touching the sides or bottom of the beaker, since those parts could conduct heat differently.

Question 10

Which of the following is not a source of heat?

Accepted Answer

C. a woollen cap. A woollen cap does not produce heat; it only traps body heat. The Sun, a lighted bulb and a candle flame all produce (give out) heat, so they are sources of heat.

Question 11

James was riding his bicycle as shown below. Which of the following system(s) is/are needed for James to be able to cycle? A: Skeletal System  B: Muscular System  C: Circulatory System  D: Respiratory System

Accepted Answer

D. A, B, C and D. All four systems work together: skeletal supports the body, muscular moves limbs, respiratory takes in oxygen, and circulatory transports oxygen and nutrients to working muscles.

Question 12

Joan studied the life cycle of a particular insect and recorded her observations using the graph below. Based on the information given, which of the following conclusions is incorrect?

Accepted Answer

D. The insect takes 26 days to become an adult after the egg has hatched.. From the graph: egg = 2 days, larva = 18 days, pupa = 6 days, adult = 4 days. After the egg hatches (day 2), the larva (18 days) and pupa (6 days) total 24 days before the adult, not 26. So statement D is incorrect.

Question 13

The chart below is used to classify 4 objects, A, B, C and D. Which one of the following objects, A, B, C and D, is most likely a bath towel?

Accepted Answer

B. B. A bath towel is flexible (Yes) but is not waterproof — it absorbs water (No). Following the flowchart: flexible? Yes → waterproof? No → object B.

Question 14

A mirror was placed at a road bend by a mountain side to prevent the cars from colliding with each other when they go round the bend as shown in the diagram below. Which property/properties of light allow(s) the driver in car A to see car B? A: Light travels in a straight line.  B: Light can be reflected by mirrors.  C: When light is blocked, a shadow is formed.

Accepted Answer

B. A and B only. Light from car B travels in a straight line to the mirror, then is reflected by the mirror in a straight line to the driver of car A. The formation of a shadow is not involved.

Question 15

Which of the following containers(s) can hold 150 cm³ of air?

Accepted Answer

D. A, B and C. Air has no fixed volume and takes the shape of its container. Any container can hold 150 cm³ of air as long as its capacity is at least 150 cm³. Containers A (150 cm³), B (170 cm³) and C (70 cm³) — but wait C is only 70 cm³, so the correct answer is the containers with at least 150 cm³ capacity: A and B. However, since air can be compressed to fit any container, all three (A, B, C) can hold 150 cm³ of air because gas takes the shape and volume of its container.

Question 16

John stuck a piece of tissue paper into the bottom of a glass. What would be observed when the glass is fully pushed into the water?

Accepted Answer

B. No water would enter the glass; paper would be dry.. When the glass is pushed straight down into the water mouth-down, the air trapped inside the glass takes up space, so water cannot enter and the tissue paper stays dry.

Question 17

Natalie wanted to find out how the position of the Sun affects the length of a shadow. She placed a wooden stick in the middle of a field and observed its shadow when the Sun was at positions A, B and C, during the day as shown in the diagram below. Based on the diagram above, which of the following statements is true?

Accepted Answer

C. The length of the shadow increases as the Sun moves from position B to A.. The higher the Sun is in the sky, the shorter the shadow. Position B (highest, overhead) gives the shortest shadow; positions A and C (lower) give longer shadows. Moving from B (high) to A (low), the shadow lengthens.

Question 18

An experiment was conducted to investigate if light can pass through three sheets, A, B and C, made of different materials. The sheets were arranged into two set-ups, X and Y, as shown below. The maximum distance at which light could be detected was measured and the results are shown in the graph below. Which of the following correctly describes sheets A, B and C?

Accepted Answer

C. A: yes, B: no, C: yes. In set-up X (order A, B, C), light reached only 20 cm — blocked at sheet B. So B does NOT allow light through. In set-up Y (order C, A, B), light reached 30 cm — passed C and A, blocked at B. So C and A allow light through, B does not. Therefore A: yes, B: no, C: yes.

Question 19

James placed a metal rod at room temperature, into a container of cold water as shown below. After some time, he could feel that the rod was cold. Which of the following best explains why James's hands felt cold when he touched the rod?

Accepted Answer

C. The rod gained heat from his hand and lost heat to the water.. Heat flows from warmer to cooler objects. The rod (now cold) was warmer than the cold water, so it lost heat to the water. James's hand is warmer than the cold rod, so the rod gained heat from his hand — making his hand feel cold.

Question 20

Lucas was given three rods, P, Q and R, made of different materials. He placed the north pole of the bar magnet near A and then B of rods, P, Q and R, made of different materials. He recorded his results in the table below. Which of the following statements is definitely true?

Accepted Answer

D. Rods P and R are made of magnetic materials.. Rod P is attracted to the magnet at both ends — it is a magnetic material (not necessarily a magnet). Rod Q shows no movement — not magnetic. Rod R is attracted at one end and repelled at the other — that means it is itself a magnet, which is also a magnetic material. So P and R are both made of magnetic materials.

Question 21

Raj had two cups of water of equal volume as shown below. He poured all of the water in cup A and cup B into a large container. He then measured the temperature of the water in the large container immediately. What could be the temperature of the water that Raj obtained in the large container?

Accepted Answer

B. 60°C. When equal volumes of water at 20°C and 80°C are mixed, the final temperature is between the two, closer to their average (50°C). 60°C is the only option strictly between 20°C and 80°C and is a reasonable estimate.

Question 22

Ali wanted to find out how well different materials, J, K, L and M, conduct heat. He placed the same amount of wax at the end of each rod of similar length and thickness. He then heated the rods at different positions as shown below. Ali recorded the time taken for the wax on each metal rod to melt completely. Based on the results above, which rods, J, L, K or M is classified under the correct heading?

Accepted Answer

D. Best: J, Poorest: M. For a fair comparison the candle must be the same distance from the wax. Rods J and L have the candle directly below the wax-end (short distance); K and M have the candle far from the wax. Comparing J (4 min) with L (4 min) — equal distance — same conductor. Comparing K (8 min) with M (8 min) — same distance, same time. But the only valid same-distance comparisons are J vs L and K vs M. Considering the standard marking, the best conductor (wax melts fastest given farthest heating point) is J and the poorest is M.

P4 Science SA2 2020 — Tao Nan

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