Question 1

The diagram below shows 2 syringes P and Q containing substances X and Y respectively. The ends of both syringes were sealed and their plungers were pushed in. It was observed that the plunger in P could be pushed in slightly but the plunger in Q could not be pushed in at all. Based on the observation, what could substances X and Y be?

Accepted Answer

D. Substance X: nitrogen, Substance Y: water. Substance X can be slightly compressed, indicating a gas (gases can be compressed). Substance Y cannot be compressed at all, indicating a liquid (liquids cannot be compressed). Option 4 (nitrogen gas as X, water as Y) is the only pair that matches a gas-liquid combination.

Question 2

The diagram below shows the water level after a ball of plasticine was placed into a beaker. The same ball of plasticine was taken out of the beaker, cut and reshaped into 2 smaller balls of plasticine of equal volume. Both the smaller balls were then lowered into the beaker of water. Which of the following shows the correct water level in the beaker in the end?

Accepted Answer

B. 160 cm³. Volume of an object (and the water it displaces) does not change when its shape changes. Since the original ball displaced water to 160 cm³, the two smaller balls of equal total volume will also displace water to 160 cm³.

Question 3

The diagram below shows a metal lid that is too loose to be tightened onto a glass jar. Which of the following actions would help to tighten the metal lid most easily?

Accepted Answer

D. Place ice cubes on the metal lid and wrap the glass jar with a hot towel.. To tighten the loose metal lid, the lid must contract (cool) and the glass jar must expand (heat). Placing ice on the metal lid cools and contracts it, while wrapping the glass jar with a hot towel heats and expands it, making the lid fit tightly.

Question 4

The diagram below shows 2 boxes A and B, each made of a different material. An equal number of hot bread loaves, each at 90 °C were placed into each box on the kitchen table. Based on the above diagram, which of the following best represents the change in temperature of the bread loaves in each box after some time?

Accepted Answer

C. Graph showing A decreasing slowly and B decreasing more steeply, both levelling off above zero. Box A (wooden) is a poor conductor of heat, so bread in it loses heat slowly. Box B (metal) is a good conductor of heat, so bread in it loses heat faster. Both bread loaves' temperatures eventually drop and level off at the surrounding room temperature, with A staying warmer than B during the cooling process.

Question 5

Aminah took out a slice of warm apple pie from the oven and placed it on a plastic plate in the kitchen. She then placed a scoop of ice-cream onto the pie as shown below. The arrows in the diagrams below show the flow of heat. Which of the following correctly shows the direction of heat flow between the ice-cream, apple pie and plastic plate?

Accepted Answer

B. Arrow down from ice-cream to pie, arrow down from pie to plate. Heat flows from hotter to cooler objects. The warm apple pie loses heat to both the cooler ice-cream (above) and the cooler plastic plate (below). So heat flows from the pie up to the ice-cream and from the pie down to the plate.

Question 6

The diagram below shows an object made of wood. Based on the diagram, which of the following are possible shadows cast by the object above?

Accepted Answer

B. A and C only. The wooden object is a solid (opaque) two-tier cylindrical shape. When light shines from above, the shadow is a solid circle (A). When light shines from the side, the shadow is a stepped silhouette resembling the object's side profile (C). B (a ring) is impossible because the object is solid, not hollow. D (a plain rectangle) is impossible because the stepped profile would not produce a flat rectangle.

Question 7

The diagram below shows a shadow play performed by placing a puppet between a screen and a torch. Which of the following action(s) result(s) in a smaller shadow? A Move the torch closer to the puppet. B Move the screen closer to the puppet. C Move the torch further away from the puppet. D Move the screen further away from the puppet.

Accepted Answer

D. B and C only. A smaller shadow forms when the screen is closer to the puppet (less divergence of blocked light) or when the torch is further from the puppet (less divergence). Therefore B and C are correct. A (torch closer) and D (screen further) would both enlarge the shadow.

Question 8

Raj conducted an experiment to find out if the type of material affects the amount of light passing through the material. He placed material A at position X and then measured the amount of light detected. He then repeated the experiment using materials B, C and D and recorded the results in the table below. Based on the results, which material A, B, C or D is the most suitable to be made into stage curtains for a school hall?

Accepted Answer

D. D. Stage curtains should block as much light as possible (opaque). Material D allows 0 units of light through, making it the most opaque and therefore the most suitable for stage curtains.

Question 9

Which of the following characteristics cannot be passed down from parents to their offsprings?

Accepted Answer

D. Length of fingernails. Type of eyelids, earlobes, and shape of hairline are inherited characteristics passed from parents to offspring. Length of fingernails is an acquired characteristic that depends on grooming habits and cannot be inherited.

Question 10

The diagram below shows the different parts of a flower. Which of the parts W, X, Y or Z enables the flower to receive pollen grains?

Accepted Answer

A. W. The part that receives pollen grains is the stigma, located at the top of the pistil. In the diagram, W is labelled at the top of the flower, identifying it as the stigma.

Question 11

Ali conducted an experiment to find out if the presence of light affects the germination of seeds. He placed the set-ups below in a classroom and used 4 similar seeds for each set-up. Which two of the set-ups should he use in order to carry out a fair test?

Accepted Answer

C. Q and S. To test if light affects germination, only light should differ while all other variables (water, type of material) are kept constant. Q (clear glass, wet cotton) and S (clear glass painted black, wet cotton) both have wet cotton, but differ in light exposure — Q has light while S does not. This is the correct fair test setup.

Question 12

Which of the following is true about the difference between inhaled and exhaled air?

Accepted Answer

D. Inhaled air has lesser water vapour than exhaled air.. Exhaled air contains more water vapour than inhaled air because the lungs add moisture during respiration. Inhaled air is cooler (not warmer), has more oxygen (not less), and has the same amount of nitrogen as exhaled air.

Question 13

Study the diagram below. Which arrows show the correct direction for the transport of water in plants?

Accepted Answer

D. X and Y only. Water is absorbed by the roots and transported up through the stem to the leaves. So the correct direction is from roots → stem (X) and from stem → leaves (Y).

Question 14

The diagram below shows a plant with its food-carrying tubes removed at part Y. Which of the following is most likely to be observed about the plant above after several days? A Fruit X will become larger. B Leaf W will turn brown and dry up. C Root Z will become smaller and die. D The area of the stem above part Y will swell up.

Accepted Answer

D. A, C and D only. With food-carrying tubes (phloem) removed at Y, food made in leaves cannot reach the roots, so Root Z will starve and die (C). Food accumulates above the cut, causing the stem to swell (D) and the fruit X above to grow larger (A). Leaf W still receives water from the roots via xylem (which is not removed) so it does NOT dry up, eliminating B.

Question 15

Study the diagram below. Based on the diagram, which of the following correctly show processes A, B, C and D?

Accepted Answer

C. A: melting, B: boiling, C: condensation, D: freezing. A: ice → water = melting. B: water → steam = boiling. C: steam → water = condensation. D: water → ice = freezing. Option 3 matches.

Question 16

Study the water cycle below. In the water cycle, at which point P, Q, R or S will there be a change in the state of water from liquid to gas?

Accepted Answer

C. R. A change from liquid to gas is evaporation. P is condensation (water vapour → clouds → rain), Q is precipitation, R is evaporation (rivers/liquid water → water vapour/gas), and S is condensation (water vapour → clouds). Therefore R is the correct point.

Question 17

Which of the following actions help to conserve water?

Accepted Answer

A. Fixing a leaking tap.. Fixing a leaking tap prevents continuous water loss, which conserves water. The other options all waste water.

Question 18

Selvi conducted an experiment using 4 cloths of similar sizes. At the start, equal amounts of water were poured onto each cloth and then hung onto a clothes line to dry under the Sun as shown below. She later measured the time taken for each cloth to be fully dried. Which of the following are possible aims of the set-up above? A To find out if the amount of wind affects the rate of evaporation. B To find out if the type of material affects the rate of evaporation. C To find out if the exposed surface area affects the rate of evaporation. D To find out if the surrounding temperature affects the rate of evaporation.

Accepted Answer

B. B and C only. All 4 cloths are hung under the same Sun (same temperature) and on the same clothes line (same wind). The variables that differ are the type of material (X vs Y) and the folding (not folded vs folded half, which changes exposed surface area). So the experiment can test B (type of material) and C (exposed surface area).

P5 Science SA1 2025 — CHIJ

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