S1 Integrated Science Practice Paper (Set 2): The Microscope And Cells, Food Energy And Nutrients, Acids And Indicators, Simple Series Circuits, Light And Shadows, Investigation Variables And Data Handling

S1 Integrated Science Practice Paper (Set 2): The Microscope and Cells, Food Energy and Nutrients, Acids and Indicators, Simple Series Circuits, Light and Shadows, Investigation Variables and Data Handling

2026-11-15

Junior Secondary Integrated Science

S1 Integrated Science practice paper, Set 2: six questions in 24 parts, 100 marks, 60 minutes on cells, food energy, acids, circuits and light, with full answers.

Paper details　S1 Integrated Science practice paper with answers: cells, food energy, acids, circuits, light and shadows.

The Microscope and Cells

A student uses a compound microscope with a 10x eyepiece and a 40x objective to observe onion epidermis cells.

#	Question	Answer and marking notes
1	Calculate the total magnification of the microscope.	Total magnification = eyepiece x objective = 10 x 40 = 400 times.
2	A cell measures 2.0 mm on the field of view. Find its actual length in micrometres.	Actual length = 2.0 / 400 = 0.005 mm = 5.0 micrometres.
3	What happens to the brightness of the field and the number of visible cells when switching from low power to high power?	The field becomes darker and fewer cells are visible because the field of view is smaller.
4	Why is methylene blue solution added before observation?	Most cells are transparent; the stain increases contrast so structures such as the nucleus are easier to see.

Food Energy and Nutrients

Energy values: carbohydrate 17 kJ/g, protein 17 kJ/g, fat 38 kJ/g. An oat bar contains 30 g carbohydrate, 10 g protein, 8 g fat and 2 g dietary fibre.

#	Question	Answer and marking notes
5	Calculate the total energy provided by one oat bar in kJ.	Energy = 30 x 17 + 10 x 17 + 8 x 38 = 510 + 170 + 304 = 984 kJ.
6	If the fat is reduced to 4 g, what is the new total energy and how many kJ are cut?	New energy = 510 + 170 + 152 = 832 kJ; cut = 984 – 832 = 152 kJ.
7	Which of the three energy-providing nutrients gives the most energy per gram?	Fat, at 38 kJ per gram, higher than the 17 kJ per gram of carbohydrate and protein.
8	Dietary fibre provides no energy. Why is it still important in a balanced diet?	Fibre adds bulk, stimulates gut movement, helps passing of stool and prevents constipation.

Acids and Indicators

The table shows the pH of four substances: Stomach acid 1.5; Lemon juice 2.0; Distilled water 7.0; Soap solution 10.0.

#	Question	Answer and marking notes
9	Which of the four substances is the most acidic?	Stomach acid, which has the lowest pH (1.5).
10	What is the pH difference between lemon juice and soap solution?	The difference is 10.0 – 2.0 = 8.0.
11	What colour change occurs when blue litmus paper is dipped into soap solution?	Blue litmus stays blue; it is red litmus that turns blue in an alkaline solution.
12	An antacid containing magnesium hydroxide is taken for too much stomach acid. Name the reaction and its two products.	Neutralisation; a salt (magnesium chloride) and water are formed.

Simple Series Circuits

Three 1.5 V cells are connected in series with two resistors (6 ohm and 3 ohm) in a series circuit.

#	Question	Answer and marking notes
13	What is the total voltage of the battery?	Total voltage = 3 x 1.5 = 4.5 V.
14	Find the total resistance and the current.	Total resistance = 6 + 3 = 9 ohm; current = 4.5 / 9 = 0.5 A.
15	Find the voltage across the 6 ohm resistor.	Voltage = 0.5 x 6 = 3.0 V.
16	Find the total power of the circuit.	Power = 4.5 x 0.5 = 2.25 W.

Light and Shadows

A light ray strikes a plane mirror with an angle of incidence of 35 degrees.

#	Question	Answer and marking notes
17	What is the angle of reflection?	Angle of reflection = angle of incidence = 35 degrees.
18	What is the angle between the incident ray and the reflected ray?	Angle = 180 – 2 x 35 = 110 degrees.
19	A person 1.6 m tall casts a 0.8 m shadow. At the same time a flagpole casts a 5.0 m shadow. Find the height of the flagpole.	Height-to-shadow ratio = 1.6 / 0.8 = 2 : 1, so the flagpole is 5.0 x 2 = 10.0 m tall.
20	What two conditions are needed for a shadow to form?	Light travels in straight lines, and an opaque object blocks the light.

Investigation and Data Handling

Five plants of the same species grow for four weeks under the same light. Their heights in cm are: 12, 15, 14, 13, 16.

#	Question	Answer and marking notes
21	Calculate the mean height of the five plants.	Mean = 70 / 5 = 14 cm.
22	Find the range of the heights.	Range = 16 – 12 = 4 cm.
23	In a study of the effect of watering amount on plant growth, what are the independent and dependent variables?	The independent variable is the amount of water; the dependent variable is plant growth (height).
24	Why grow five plants per group instead of one?	To reduce the effect of individual variation and make the result more reliable.

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