P4 Science SA1 2025 — Nan Chiau

Q: The diagram below shows a floating water plant in a tank. Which one of the following is correct?

A. Part X — leaf — makes food. Part X is the leafy part above the water, which makes food through photosynthesis. Part Y is the root, which absorbs water and mineral salts (not 'only nutrients').

Q: The diagram below shows a tree being blown by strong wind. The ____ of the tree prevented it from being blown away by the strong wind.

B. roots. Roots anchor a plant firmly into the ground, preventing it from being blown away. The stem holds the plant upright but does not anchor it; leaves and branches do not anchor the plant.

Q: Caius prepared two similar setups A and B and placed them under the Sun for two days as shown below. Which of the following shows the amount of water left in each setup after two days?

C. A = 75 ml, B = 100 ml. In setup A, the plant's roots are in the water and the leaves are exposed, so the plant can absorb water and lose it through transpiration — water level decreases (75 ml). In setup B, the roots are wrapped in a plastic bag, so the plant cannot absorb water from the flask; the water remains unchanged at 100 ml.

Q: The diagram below shows part of a human skeleton. Part X protects the ____. A: brain B: heart C: lungs

D. B and C only. Part X points to the rib cage. The rib cage protects the heart and the lungs, but not the brain (which is protected by the skull).

Q: The diagram below shows parts of the human digestive system. Which of the following letters are correctly matched to its function?

D. Digested food absorbed into bloodstream: H; Water absorbed from undigested food: G. F is the stomach, G is the large intestine, H is the small intestine. Digested food is absorbed into the bloodstream in the small intestine (H), and water is absorbed from undigested food in the large intestine (G).

Q: The diagram below shows a syringe that is connected to a container. When the plunger is pushed in completely, 50 cm³ of air is pushed into the container. What would be the volume of air in the container after fully pushing the plunger twice?

C. 250 cm³. The 300 cm³ container already holds 150 cm³ of water, leaving 150 cm³ of space initially occupied by air. Pushing the plunger twice adds 50 + 50 = 100 cm³ of air. Total air in the container = 150 + 100 = 250 cm³.

Q: Mary bought a cup of juice as shown in diagram 1. While drinking the juice through a straw, she observed some juice inside the straw as shown in diagram 2. From her observation only, Mary concluded that the juice ____.

C. has no definite shape. The juice took the shape of the cup in diagram 1 and the shape of the straw in diagram 2. This shows that the juice has no definite shape — it takes the shape of its container.

Q: Study the flowchart below. Which of the following items correctly represent X, Y and Z?

C. X = air, Y = milk, Z = rock. Flowchart asks 'Does it have a definite volume?' — No → X (gas). Air has no definite volume, so X = air. Yes → 'Does it have a definite shape?' — No → Y (liquid). Milk has no definite shape, so Y = milk. Yes → Z (solid). Rock has both definite volume and definite shape, so Z = rock.

P4 Science 2025 SA1 13 questions 22 marks

Source: Nan Chiau, 2025

This P4 Science SA1 paper from Nan Chiau (2025) contains 13 questions worth 22 marks. Use it as a study reference for Science topics typically tested at P4 level in Singapore schools.

Q1 MCQ 1 mark 🖼 Visual

The diagram below shows a floating water plant in a tank. Which one of the following is correct?

Q2 MCQ 1 mark 🖼 Visual

The diagram below shows a tree being blown by strong wind. The ____ of the tree prevented it from being blown away by the strong wind.

Q3 MCQ 1 mark 🖼 Visual

Caius prepared two similar setups A and B and placed them under the Sun for two days as shown below. Which of the following shows the amount of water left in each setup after two days?

Q4 MCQ 1 mark 🖼 Visual

The diagram below shows part of a human skeleton. Part X protects the ____. A: brain B: heart C: lungs

Q5 MCQ 1 mark 🖼 Visual

The diagram below shows parts of the human digestive system. Which of the following letters are correctly matched to its function?

Q6 MCQ 1 mark 🖼 Visual

The diagram below shows a syringe that is connected to a container. When the plunger is pushed in completely, 50 cm³ of air is pushed into the container. What would be the volume of air in the container after fully pushing the plunger twice?

Q7 MCQ 1 mark 🖼 Visual

Mary bought a cup of juice as shown in diagram 1. While drinking the juice through a straw, she observed some juice inside the straw as shown in diagram 2. From her observation only, Mary concluded that the juice ____.

Q8 MCQ 1 mark 🖼 Visual

Study the flowchart below. Which of the following items correctly represent X, Y and Z?

Q9 Structured 4 marks 🖼 Visual

Peter placed two similar potted plants A and B in a field. He only watered plant A. A few days later, he observed that plant A continued to grow healthily while plant B had withered. (a) What type of stem do both plants A and B have? [1] (b) Explain how the poles help both plants when making food. [2] (c) Explain why plant B withered. [1]

Q10 Structured 2 marks 🖼 Visual

The diagrams below show two different types of flowering plants E and F. (a) What is the function of part X? [1] (b) The roots of plant E are more widely spread than the roots of plant F. Give one advantage of having more widely spread roots. [1]

Q11 Structured 2 marks 🖼 Visual

The graph below shows the amount of undigested food as it leaves each part of the human digestive system. (a) Identify part G and part H of the human digestive system. Part G: ____ Part H: ____ [1] (b) Explain why the amount of undigested food that leaves both the large intestine and small intestine is the same. [1]

Q12 Structured 3 marks 🖼 Visual

Jenny attached a balloon to the mouth of a plastic bottle with its bottom cut off as shown in the diagram. (a) When she pushed the bottle into the water, the balloon became inflated. Explain why this happened. [1] Jenny removed the balloon and sealed the mouth of the opening. She repeated the experiment and pushed the bottle into the water. (b) Draw the water level in the bottle. [1] (c) Explain your answer in (b). [1]

Q13 Structured 3 marks 🖼 Visual

Lucas pumped air into a travel pillow as shown in the diagram. (a) Which physical property of air does this show? [1] (b) Did the mass of the travel pillow increase, decrease or remain the same after Lucas pumped air into it? Give a reason for your answer. [1] The pillow is sealed and can be pressed down a little when someone is lying on it. (c) Which physical property of air allowed the pillow to be pressed down? [1]

P4 Science SA1 2025 — Nan Chiau

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