P6 Science CA1 2025 — Raffles Girls

The table shows the composition of some gases found in both the inhaled and exhaled air of Ali. (a) Based on the information found in the table above, fill in the blanks, (a)(i) and (a)(ii), with the correct words, 'inhaled' or 'exhaled'. [2] (b) Name another gas that is found in higher percentage in the exhaled air than the inhaled air. [1]

George placed a potted plant shown in diagram X in a dark room for two days. [Diagram X: a potted plant with several leaves]. After two days, leaf C was covered completely with black cardboard and leaf D was placed in a transparent plastic bag which contained a substance that removed carbon dioxide as shown in diagram Y. The potted plant was then placed in the garden. [Diagram Y: same potted plant labelled with leaf B (uncovered), leaf C covered by black cardboard, and leaf D enclosed in a plastic bag containing a substance that removes carbon dioxide]. (a) Which two leaves, B, C and/or D, should George compare to find out if carbon dioxide is needed for photosynthesis? [1] (b) How would the amount of oxygen in the plastic bag change over time? Give a reason for your answer. [1] (c) George conducted a starch test on leaf C using iodine solution. Iodine is a brown solution that turns blue-black in the presence of starch. What would the colour of iodine be when it is placed on the leaf? Explain your answer. [2]

Nina wanted to find out if the intensity of light would affect the rate of photosynthesis. She conducted an experiment using the set-up shown in the diagram. . (a) State a reason why Nina should conduct the experiment in a dark room. [1] (b) In the table below, put a tick (✓) in the correct boxes to identify the dependent and constant variables for Nina's experiment. [Table with columns 'Variables', 'Dependent / Measured Variable(s)', 'Constant Variable / Variable to keep the same'; rows: Amount of water; Type of water plant; Height (h) in boiling tube after five minutes; Distance (d) between the lamp and the beaker; Amount of carbon dioxide in the water at the start of the experiment] [3] (c) After a few minutes into the experiment, Nina observed bubbles appearing from the leaves of the plant. Name the gas produced by the leaves. [1]

Sally heated a beaker of ice over a period of time and recorded the change in temperature in the graph below. [Graph: Temperature (°C) vs Time (min). The line starts at 0°C at about t=5 min, rises steadily to 100°C at about t=20 min, stays flat at 100°C until about t=40 min, then falls steadily to 20°C at about t=60 min and remains at 20°C until t=80 min.] Based on the information above, answer the following questions: (a) When did boiling start? [1] (b) State the room temperature. [1] (c) State a difference between the process of boiling and evaporation. [1]

Ellen placed the following set-up in a room with a constant temperature of 25°C. She heated the water until it started to boil. Ellen observed water droplets forming on identical trays, P and Q, and water was collected in both beakers, S and T. . (a) Describe how water was collected in both beakers, S and T. [2] Ellen measured the amount of water collected in beakers S and T over a few minutes and recorded it in the graph shown. [Graph: Amount of water collected (ml) vs Time (min); line A rises faster and higher than line B, both starting from origin and curving upward then levelling off, with line A above line B]. (b) Which line, A or B, shows the amount of water collected in beaker S? Explain your answer. [2]

(a) Mahit bought a new torch. The torch has a removable plastic strip inserted as shown in the diagram. . (i) Nelly suggested to Mahit that the plastic strip needs to be removed so that the torch will light up when the switch was pressed down in the direction as shown in the diagram. Do you agree with Nelly? Why? [1] The following diagram shows part of the circuit of the torch. [Diagram: a rectangular outline containing two batteries (drawn as vertical cell pairs) and a bulb on the right, with the rest of the circuit incomplete]. (ii) Complete the circuit diagram above by using one switch and some wires so that the torch will light up. [1] (b) Study the circuit shown in the diagram below. Three identical batteries and two identical bulbs, L and M, were used. [Diagram: a circuit with three batteries; a metal lever resting on a support, with a metal spring under a button at the left end of the lever; when the button is pushed down the lever lifts off contact, and when released the spring pushes it back; bulb L is connected such that the circuit through it closes when the lever is in one position, and bulb M is connected via a separate path that closes in the other position]. (i) Put a tick (✓) in the correct boxes, to indicate if the bulb will light up when the button is pushed downwards or released. [Table: Action | Bulb L lights up | Bulb M lights up; rows: Button pushed downwards; Button is released] [1] (ii) Explain why the spring and the lever need to be made of metal. [1]

The diagram shows three identical kettles, A, B and C. The heating elements used to heat up the water, are made of the same material but are of different shapes. . Layla poured the same amount of water into each kettle and measured the time taken for the water in each kettle to boil. The results are as shown in the result table below. [Table: Time taken for water to boil (minutes) — (a)(i) Kettle ___ : 10; (a)(ii) Kettle ___ : 6; Kettle A : 3]. (a) Based on the information above, write down kettle 'B' or 'C' in the correct boxes (a)(i) or (a)(ii), in the result table. [1] (b) Explain why the water in kettle A took the shortest time to boil. [2]

Annie conducted an experiment using set-ups P and Q. She wrapped identical beakers with materials R and S, in set-ups P and Q as shown in the diagram. Then, she filled both beakers with the same volume of hot water at the same temperature, T. . The diagram below shows the temperature, T, of the hot water in both set-ups. [Diagram: a thermometer with a zoomed view showing the mercury level between 80 and 90, at the third mark above 80, i.e. 83°C]. (a) What is the reading shown on the thermometer? [1] Annie recorded the change in temperatures of the water in both beakers in the graph shown. [Graph: Temperature (°C) vs Time (min); both lines start at T and slope downwards; set-up Q's line decreases more gradually (less steep) while set-up P's line decreases more steeply, ending lower]. (b) Based on the graph, state the change in temperature of water in the beakers over time. [1] (c) Which material, R or S, should Annie use to make an ice-cream box to store ice-cream? Explain your answer. [2]