Question 1

Study the flowchart below. Which one of the following best represents a mosquito?

Accepted Answer

D. D. A mosquito lays eggs (Yes), lays its eggs in water (Yes), and has 4 stages in its life cycle — egg, larva, pupa, adult (Yes). Following all 'Yes' branches leads to box D.

Question 2

The graph below shows the change in the mass of the seed leaves of a young plant over a period of 5 days. Sarah, Johan, Keith and Diana wrote the following statements based on the graph above.
Sarah: The mass of the seed leaves will increase after Day 5.
Johan: The leaves will make food for the young plant after Day 4.
Keith: The young plant will die as the mass of the seed leaves decreases.
Diana: The seed leaves provide food for the young plant from Day 1 to Day 4.
Whose statements are correct?

Accepted Answer

C. Johan and Diana. The seed leaves store food and supply it to the young plant; their mass decreases as the food is used up (Days 1–4), so Diana is correct. After the seed leaves are used up, the young plant's true (foliage) leaves take over to make food by photosynthesis, so Johan is correct. The seed leaf mass will not increase again (Sarah wrong) and the plant does not die — it switches to making its own food (Keith wrong).

Question 3

Which one of the following shows the correct sequence of processes in the sexual reproduction of flowering plants?

Accepted Answer

B. pollination → fertilisation → seed dispersal → germination. The correct cycle of sexual reproduction in flowering plants is pollination → fertilisation → seed dispersal → germination, then the new plant grows and the cycle repeats.

Question 4

Salina placed the same type of seeds in four identical containers as shown below. She covered set-ups A and B with an airtight lid, and placed the four set-ups next to the window at room temperature. In which set-up(s) would the seeds most likely start to germinate?

Accepted Answer

B. A and C only. Seeds need water and air (oxygen) to germinate. Set-up A is airtight with damp cotton wool and a liquid that absorbs carbon dioxide (oxygen still present) — germinates. Set-up B is airtight with a liquid that absorbs oxygen — no oxygen, will not germinate. Set-up C is open with damp cotton wool (water + air) — germinates. Set-up D has dry cotton wool (no water) — will not germinate. So A and C only.

Question 5

The table below describes the differences in sexual reproduction between a flowering plant and a human. The table shows: Female reproductive cell — Plant: ovule, Human: S; Male reproductive cell — Plant: pollen grain, Human: P; Formed after fertilisation — Plant: seed, Human: Q. Which one of the following correctly identifies S, P and Q?

Accepted Answer

B. S: egg, P: sperm, Q: foetus. In humans, the female reproductive cell is the egg (S), the male reproductive cell is the sperm (P), and the structure formed after fertilisation that develops is the foetus (Q).

Question 6

Zul has an aquarium filled with water plants and fishes. He connected a datalogger to his aquarium to measure the amount of oxygen in the aquarium over a 24 hr period. The graph from the datalogger shows the following information. At which part of the graph was the plant unable to make food?

Accepted Answer

B. From B to C only. When there is no light, the plant cannot photosynthesise (make food), so it only respires, using up oxygen. The amount of oxygen falls only during the B to C section of the graph, indicating the plant was unable to make food then.

Question 7

Three test tubes were set up as shown below. At the start of the experiment, the indicator in each test tube is blue. In the presence of an increased amount of carbon dioxide, the indicator changes from blue to red. What will be the colour of the indicator in each test tube after two hours?

Accepted Answer

D. W: blue, X: blue, Y: red. Tube W contains only stones (non-living), so no carbon dioxide is produced — stays blue. Tube X contains a green leaf in light, which photosynthesises and takes in carbon dioxide — stays blue. Tube Y contains insects which respire and give out carbon dioxide — turns red. So W blue, X blue, Y red.

Question 8

Stanley carried out an experiment on photosynthesis. He set up the apparatus as shown below. When the lamp was switched on, he observed bubbles in the water. Which of these variables can affect the number of bubbles produced by the water plant?
A: Size of the test-tube
B: Distance from the lamp
C: Brightness of the lamp
D: Amount of oxygen dissolved in the water

Accepted Answer

C. B and C only. The bubbles are oxygen produced by photosynthesis, which depends on the amount of light reaching the plant. The distance from the lamp (B) and the brightness of the lamp (C) both change the light intensity, affecting the rate of photosynthesis and number of bubbles. Test-tube size and dissolved oxygen do not affect how much the plant photosynthesises.

Question 9

Emma set up an experiment as shown below. She wrapped three similar leaves in different types of plastic bags of the same size. She placed the potted plant under the sun for several hours. Which of the following graphs represents the amount of carbon dioxide in the plastic bags at the end of her experiment?

Accepted Answer

C. Graph 3: A low, B high, C medium. Leaf A (clear bag) gets full light, photosynthesises actively and uses up carbon dioxide — lowest carbon dioxide. Leaf B (black bag) gets no light, cannot photosynthesise but still respires, releasing carbon dioxide — highest carbon dioxide. Leaf C (clear bag with tiny holes) gets light and photosynthesises, but gas exchanges through the holes — carbon dioxide is in between. So A low, B high, C medium (Graph 3).

Question 10

Which one of the following properties can differentiate a liquid from a gas?

Accepted Answer

D. Has a definite volume. Both liquids and gases have mass and occupy space, and neither has a definite shape. However, a liquid has a definite volume while a gas does not, so this property differentiates them.

Question 11

Ali has a football which can hold 350cm³ of air. He used a syringe and removed 80cm³ of air from the football as shown in the diagram below. How did the volume of the air in the football and the mass of the football change?

Accepted Answer

D. Volume of air: remained the same, Mass: decreased. The football keeps its shape, so the air inside still fills the whole football — the volume of air remains the same (350cm³). However, removing 80cm³ of air removes some mass of air, so the mass of the football decreases.

Question 12

An experiment was conducted on 3 different objects (R, S and T). Each object was placed into measuring cylinders A, B and C respectively, filled with 80ml of water at the start. Which of the following can be concluded about objects R, S and T?
A: Object T has the largest volume.
B: Object T has a greater mass than Object R.
C: Object S has a greater volume than Object R.
D: Objects S and T have the same mass and volume.

Accepted Answer

B. A and C only. Object R is fully submerged and raises the water from 80ml to 85ml (displaces 5ml). Object S is fully submerged and raises the water to 90ml (displaces 10ml), so S has greater volume than R (statement C correct). Object T floats (it leans/tilts at the surface), so although it raises the water to 90ml, its actual volume is larger than its displacement — T has the largest volume (statement A correct). Floating only tells us about density, not mass, so we cannot conclude B or D. So A and C only.

Question 13

Mrs Tan took a piece of frozen meat covered with ice and placed it on a tray as shown in the diagram below. After some time, water appeared on the tray and the meat was not frozen. Based on the above observations, which one of the following is NOT correct?

Accepted Answer

D. water vapour in the air — gained heat. The ice melted, so it gained heat (correct). The frozen meat thawed, so it gained heat (correct). The tray's surface became cold and water droplets formed on it, so the tray lost heat (correct). The water droplets on the tray formed because water vapour in the air condensed — to condense, water vapour must LOSE heat, not gain it. So 'water vapour gained heat' is NOT correct.

Question 14

Andy poured equal volumes of water at room temperature into three cups of different material. He placed the cups in a tub of hot water as shown below and covered each cup with a wooden lid. He measured the temperature of water in each cup after some time. Andy concluded that the material of cup B was the best conductor of heat. What was the most likely observation for Andy to make such a conclusion?

Accepted Answer

D. The increase in the temperature of water in cup B was the highest.. A better conductor lets heat from the hot water in the tub pass into the room-temperature water faster, so its temperature rises more in the same time. If cup B is the best conductor, the increase in temperature of the water in cup B would be the highest.

Question 15

The diagram below shows the change of state for water. ICE ⇌ WATER ⇌ STEAM, where Process 1 is ICE→WATER, Process 2 is WATER→STEAM, Process 3 is WATER→ICE, and Process 4 is STEAM→WATER. What are the names of the processes?

Accepted Answer

D. Process 1: melting, Process 2: boiling, Process 3: freezing, Process 4: condensation. Ice → water is melting (Process 1). Water → steam is boiling/evaporation (Process 2). Water → ice is freezing (Process 3). Steam → water is condensation (Process 4).

Question 16

The diagram below shows the number of animals A, B and C found in a stream at locations 1, 2 and 3 after the factory was built. Waste is released into the water by the factory. Mr Tan wants to conclude that the animals B and C are most affected by the factory waste. Which one of the following information does he need?

Accepted Answer

C. The number of animals A, B and C at the three locations before the factory was built.. To know whether the factory waste affected the animals, Mr Tan must compare the numbers before and after the factory was built. Without the 'before' numbers he cannot tell if the change was caused by the waste, so he needs the number of animals A, B and C at the three locations before the factory was built.

Question 17

Which of the following best matches the main form of energy present in the diagram shown? The pictures are Running water, Food, Lightning strikes a tree, and Boy on diving board.

Accepted Answer

C. Running water: Kinetic energy, Food: Potential energy, Lightning strikes a tree: Heat energy, Boy on diving board: Potential energy. Running water is moving, so it has kinetic energy. Food stores chemical/potential energy. Lightning striking a tree releases heat energy (the main form that affects the tree). A boy standing on a high diving board has potential energy due to his height. So the matches are kinetic, potential, heat, potential.

Question 18

The diagram show 4 objects which are hung from the ceiling. Which of the following statement(s) is/are correct?
A: Object X has more potential energy than object Z.
B: Object Z has more potential energy than object Y.
C: Objects W and Y have the same amount of potential energy.

Accepted Answer

B. A and B only. Potential energy depends on both mass and height. X (90g) hangs higher than Z (90g), so X has more potential energy (A correct). Z (90g) and Y (80g) hang at the same lower height, so heavier Z has more potential energy than Y (B correct). W (80g) hangs higher than Y (80g), so although same mass, they are at different heights and do NOT have the same potential energy (C wrong). So A and B only.

Question 19

John conducted an experiment to find out if the speed of a car affects the amount of kinetic energy it has. He plotted his results as shown below. Based on the graph, what conclusion(s) can be drawn?
A: The car has no kinetic energy when it is at rest.
B: The faster the car moves, the more kinetic energy it has.
C: The mass of the car does not affect the amount of kinetic energy it has.

Accepted Answer

B. A and B only. The straight line passes through the origin, so at zero speed (at rest) kinetic energy is zero (A correct). The line rises as speed increases, so faster speed gives more kinetic energy (B correct). The experiment only changed speed, not mass, so nothing can be concluded about the effect of mass (C wrong). So A and B only.

Question 20

Xavier carried out an experiment with a pendulum as shown in the diagram below. He released the metal ball at position A and let it swing to position C and then back to position D. Which one of the following graphs shows the change in kinetic energy of the metal ball as it swung from A to C and then back to D passing through position B at both times?

Accepted Answer

C. Graph 3. B is the lowest point of the swing (maximum kinetic energy) and A and C are the highest points (zero kinetic energy). As the ball swings A→B→C→B→D, kinetic energy starts at 0 at A, rises to maximum at B, falls to 0 at C, rises to maximum at B again, then drops toward D. Graph 3 shows the two equal maximum peaks at the B positions and zeros at A and C.

Question 21

A rubber ball was dropped onto the floor as shown in the diagram below. The ball bounced several times making a sound each time it hit the floor. Which one of the following statements is true about the energy in the ball as it moved from position X to position Y?

Accepted Answer

B. The ball has more kinetic energy at position X than at position Y.. Each bounce loses some energy as sound and heat, so the ball bounces lower and moves slower each time. Position X is an earlier bounce than position Y, so the ball has more kinetic energy at X than at Y. (It is not zero, and at X energy is also lost to sound, not only kinetic.)

Question 22

Jason placed two different cubes on two identical springs. As a result, the springs, as shown in set-ups A and B, were compressed as shown below. Based on his observation, Jason can conclude that ____

Accepted Answer

B. The spring in A has less potential energy than in B.. The spring in B is compressed more than the spring in A. The more a spring is compressed, the more elastic potential energy it stores. So the spring in A (less compressed) has less potential energy than the spring in B.

Question 23

When a force is applied to an object, which of the following is not an effect of the force?

Accepted Answer

C. The object increases in mass.. A force can start or stop motion, change speed, change direction, rotate, or change the shape of an object. A force does not change an object's mass, so 'the object increases in mass' is not an effect of force.

Question 24

Ball X is not moving. Ball Y is moving towards ball X. What will happen to Ball X when Ball Y touches it?

Accepted Answer

B. Starts moving. Ball X is at rest. When the moving Ball Y collides with it, Y exerts a force on X, which makes the stationary Ball X start moving.

Question 25

Faith set up an experiment by letting a steel ball swing from point A to point C. It took 15 seconds to come to rest at position B. She repeated the experiment by placing different objects X, Y and Z under position B respectively, using the identical set-up above. The results obtained are shown in the table below: Object X — 3 seconds, Object Y — 10 seconds, Object Z — 15 seconds (time taken for the ball to come to a complete stop at B). Based on the results obtained, which one of the following deductions can be made?

Accepted Answer

C. Object Y is a weaker magnet than object X.. Without any object the steel ball stops in 15 seconds. A magnet under B attracts the steel ball and makes it stop faster. Object X stops it in 3s (strong attraction), Object Y in 10s (weaker attraction), so Y is a weaker magnet than X (correct). Object Z gives 15s, the same as no object, so it has no magnetic effect — but we cannot conclude it is a 'metal' (it could be any non-magnetic material), so D is not a valid deduction.

Question 26

Mr Quek used a large force to push two boxes up a slope as shown in Diagram 1. Then, he moved the same two boxes with a trolley up the same slope using a smaller force as shown in Diagram 2. Which one of the following statements explains why Mr Quek used a smaller force to push the boxes with a trolley?

Accepted Answer

A. Friction is reduced.. The trolley has wheels which roll, reducing the area in contact with the ground and therefore reducing friction. With less friction, a smaller force is needed to move the boxes up the slope. The mass and weight of the boxes are unchanged, and friction is not completely removed.

Question 27

Chloe placed four iron rings A, B, C and D through a smooth plastic rod in three different arrangements as shown below. Based on the observation above, which of the following iron rings are definitely magnets?

Accepted Answer

C. A, B and C only. A ring that floats above another on the rod must be repelling it, and only two magnets repel — so a floating ring and the ring directly below it must both be magnets. Across the three arrangements, rings A, B and C are each seen floating (showing repulsion), so they are definitely magnets. Ring D is never observed floating, so it cannot be confirmed as a magnet (it could be an ordinary iron ring attracted/resting). So A, B and C only.

Question 28

Joshua conducted an experiment with blocks of different masses. He released the blocks from the top of the ramps with different surfaces as shown below. Set-up P: 600g block on a wooden surface ramp (30cm). Set-up Q: 300g block on a carpeted surface ramp (30cm). Set-up R: 150g block on a wooden surface ramp (30cm). Set-up S: 300g block on a wooden surface ramp (30cm). He wanted to investigate how the time taken by the block to slide down the ramp depends on the mass of the block and the surface of the ramp. Which pairs of set-ups should he use in his investigation?

Accepted Answer

B. Mass of the block: R and S; Surface of the ramp: Q and S. To investigate the effect of mass, keep the surface the same and change only the mass: R (150g, wooden) and S (300g, wooden) — same wooden surface, different mass. To investigate the effect of surface, keep the mass the same and change only the surface: Q (300g, carpeted) and S (300g, wooden) — same mass, different surface. So Mass: R and S; Surface: Q and S.

P6 Science CA1 2017 — Rosyth

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P6 Science CA1 2017 — Rosyth

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