Question 1

The structures below are grouped according to the body systems that they belong to. Which one has been placed incorrectly?

Accepted Answer

B. Lungs. Lungs is placed under the Digestive system in the table, but lungs belong to the Respiratory system. The gullet, skull, backbone, heart and blood in blood vessels are correctly grouped.

Question 2

Which of the following systems work together to help Fiona run?
A. Respiratory system
B. Circulatory system
C. Muscular system
D. Skeletal system

Accepted Answer

D. A, B, C and D. Running requires the muscular and skeletal systems for movement, the respiratory system to take in oxygen, and the circulatory system to deliver oxygen and digested food to the muscles. All four systems work together.

Question 3

Which one of the following systems delivers digested food and oxygen to all parts of the body?

Accepted Answer

C. Circulatory System. The circulatory system uses blood pumped by the heart through blood vessels to transport digested food (absorbed from the small intestine) and oxygen (absorbed in the lungs) to every part of the body.

Question 4

Digestion takes place at the ____.
A: Mouth
B: Gullet
C: Stomach
D: Small intestine
E: Large intestine

Accepted Answer

B. A, C and D only. Digestion occurs in the mouth (chewing and saliva break down food), the stomach (churning and gastric juice) and the small intestine (digestive juices complete digestion). The gullet only transports food, and the large intestine only absorbs water from undigested food.

Question 5

Which of the following functions does not match with the human body system?

Accepted Answer

B. Muscular — protects our vital organs. The muscular system enables movement, not the protection of vital organs. It is the skeletal system that protects vital organs such as the brain, heart and lungs. (The respiratory option is also imperfectly worded, but the muscular row is the canonical mismatch.)

Question 6

Study the diagram below. Which of the following is correct?

Accepted Answer

A. A: Small intestine, B: Large intestine, C: Digested food, D: Water. Food travels Mouth → Gullet → Stomach → Small intestine (A), which absorbs digested food (C) into the blood. The remaining undigested food passes into the Large intestine (B), which absorbs water (D). What is left exits through the rectum.

Question 7

A syringe is filled with an equal volume of air and water. The nozzle of the syringe is covered tightly by a finger as shown below. Which of the following is true when the plunger is pushed in?

Accepted Answer

B. Volume of Air: Decrease; Volume of Water: No Change. Air (a gas) can be compressed, so its volume decreases when the plunger is pushed in. Water (a liquid) cannot be compressed, so its volume stays the same.

Question 8

Study the table below. Which object is not ticked correctly?
√ means 'has that property', X means 'does not have that property'.

Accepted Answer

C. Oxygen. Oxygen is a gas and has neither a definite shape nor a definite volume. The table ticks 'Definite Shape' for Oxygen, which is wrong; it should be a cross.

Question 9

Karen placed Object A into a beaker of 150 cm³ of water. The water level then rose to 300 cm³. She removed Object A and cut it into two separate pieces. The diagram below shows the water level when she placed the two cut pieces of Object A back into the beaker. From the above observation, what can Karen conclude about the properties of Object A?
A) Has mass
B) Can be compressed
C) Has definite volume
D) Has no definite volume

Accepted Answer

A. C only. Object A displaced 150 cm³ of water both as a whole piece and after being cut, so its volume stayed the same despite a change in shape. This shows Object A has a definite (fixed) volume. The experiment does not give information about mass or compressibility.

Question 10

Study the diagram shown below. What is the volume of the liquid shown above?

Accepted Answer

C. 36 cm³. The zoomed-in view of the measuring cylinder shows the meniscus sitting between the 30 cm³ and 40 cm³ markings, six small divisions above 30 cm³. The correct reading is 36 cm³.

Question 11

When more air is pumped into a volley ball as shown in the diagram below, it does not get any bigger. Which one of the following property of air does the above diagram show?
This shows that air ____.

Accepted Answer

C. can be compressed. More air can be forced into the volleyball without changing its size, which means the air inside is being squeezed into the same space. This shows that air can be compressed.

Question 12

Which one of the following diagrams shows the correct water level in the container when the container is placed on the table after awhile?

Accepted Answer

A. Diagram (1). Water is a liquid with no definite shape. Regardless of how the container is tilted, the water surface always settles horizontally (parallel to the table). Only diagram (1) shows the water surface horizontal relative to the table.

Question 13

Which one of the following is a source of light?

Accepted Answer

C. lit candle flame. A source of light produces its own light. A lit candle flame produces its own light. Hot tea gives off heat, not light; the moon only reflects sunlight; a book does not produce light on its own.

Question 14

Judy wanted to find out if the distance between the torch and the shoe affects the size of the shadow formed on the screen. Which of the following setups would result in the smallest shadow formed on the screen?

Accepted Answer

D. Setup (4). The shadow is smallest when the object is closest to the screen (and therefore furthest from the torch). In setup (4) the shoe is right next to the screen while the torch is far away, so the shoe blocks the smallest area of light and forms the smallest shadow.

Question 15

Sam wanted to find out how the thickness of an object affects the amount of light detected by the light sensor as shown in the experiment below. Which of the following variables should be kept the same to ensure a fair test?
A: The thickness of the object.
B: The amount of light from the torch.
C: The type of material used for the object.
D: The distance between the light sensor and the object.

Accepted Answer

C. B, C and D only. The variable being changed (independent variable) is the thickness of the object, so A must not be kept the same. To make it a fair test, all other variables — the amount of light from the torch (B), the type of material of the object (C) and the distance between the light sensor and the object (D) — must be kept constant.

Question 16

Xue Ling stood under a lamp as shown in the diagram below. She walked from position W to position X and then to position Y in a straight line. Which graph shows how the length of her shadow changes at different positions?

Accepted Answer

D. Graph (4) — small at W, peak at X, low at W, higher peak at Y. Directly under the lamp at W the shadow is very short. Walking outwards to X the shadow lengthens, then shrinks again as she returns to W, then lengthens once more (and even more, since Y is further from W than X) as she walks to Y. Graph (4) shows this rise–fall–larger rise pattern.

Question 17

An experiment was carried out in a dark room as shown below. Sheets A, B and C were arranged in a straight line. When the torch was switched on, a bright triangular patch of light was seen on sheet C only. Which one of the following correctly describes the properties of the sheets?

Accepted Answer

D. Allows most light to pass through: A; Does not allow light to pass through: B and C. For light to reach sheet C, it must first pass through sheet A — so sheet A is transparent. Sheet B blocks light except where the triangular hole is, so sheet B is opaque. The bright patch is seen on sheet C, meaning light is stopped on C — so sheet C is also opaque. Hence A allows light through; B and C do not.

Question 18

Which of the following is not a source of heat?

Accepted Answer

A. gloves. Gloves do not produce heat — they only trap the heat from your hands. The Sun, fire and boiling water in a kettle all give off heat, so they are sources of heat.

Question 19

Devi used an electric iron to iron her clothes as shown below. She is able to hold the electric iron using the plastic handle because plastic is a ____.

Accepted Answer

C. poor conductor of heat. Plastic is a poor conductor of heat (an insulator). Heat from the hot iron does not flow through the plastic handle to Devi's hand, allowing her to hold the iron safely.

Question 20

Fandi has 4 beakers of water, W, X, Y and Z with different volumes and temperatures as shown below. W: 50 ml at 90°C. X: 30 ml at 90°C. Y: 50 ml at 60°C. Z: 10 ml at 60°C. He wants to find out if ice melts faster in water with a higher temperature. Which two beakers should he use in his experiment?

Accepted Answer

B. W and Y. To test whether water temperature affects how fast ice melts, the only variable that should change is temperature; the volume of water must stay the same. W (50 ml at 90°C) and Y (50 ml at 60°C) have the same volume but different temperatures, so they form a fair test.

Question 21

Study set-ups X and Y below. Set-up X has a wet cloth at 80°C wrapped around a round flask connected by a tube to a basin filled with water (the tube end is labelled S). Set-up Y is identical but the wet cloth is at 5°C. Which of the following could be observed two minutes after the cloth was placed on the flask in set-ups X and Y?

Accepted Answer

C. Set-up X: Bubbles escaped from the tube at S; Set-up Y: Water entered the tube and rose up. In Set-up X the 80°C cloth heats the air inside the flask. The air expands and is pushed out through the tube, so bubbles escape at S in the water basin. In Set-up Y the 5°C cloth cools the air inside, so the air contracts and water from the basin is pushed up into the tube.

Question 22

Mr Raju prepared his 'teh tarik' (pulled tea) by pouring the hot tea from a metal container to another metal container repeatedly as shown in the diagram below. He poured the tea back and forth repeatedly between the two metal containers from a height to ensure that the tea is not too hot for the customers to drink. Which of the following correctly explains why the tea was less hot after Mr Raju's action?

Accepted Answer

B. The hot tea will lose heat faster to the surroundings.. Heat flows from a hotter object to a cooler one. Pouring the tea from a height stretches it into a long, thin stream, greatly increasing the surface area of hot tea in contact with the cooler surrounding air. This makes the tea lose heat to the surroundings faster, so it cools down. (Coldness does not travel; heat does.)

P4 Science SA1 2023 — St Hildas

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