Cambridge IGCSE Co-ordinated Sciences 0654/52 is the May/June 2026 Paper 5 (Practical Test), variant 2. It lasts 2 hours, is worth 60 marks and is sat by Core and Extended candidates whose school enters them for the practical test rather than Paper 6. It had six compulsory questions, two each in biology, chemistry and physics, and the biggest was Question 3, a 15-mark chemistry experiment to find the water of crystallisation in washing soda. This guide goes through the paper question by question and shows what the official mark scheme gave marks for. The paper and its mark scheme are free on the Tutopiya Learning Portal.

For an overview of all six 0654 papers from this series, see IGCSE Co-ordinated Sciences 0654 May/June 2026 past papers: what came up and how it was marked.

Paper 5 and Paper 6 used the same six investigations in the same order. The 0654 Paper 62 guide shows the same experiments with fixed readings, so you can check your working against definite answers.

0654/52 at a glance

Question	Topic	Marks	Main command word
1	Biology: catalase in celery puree, foam height with 2 cm³ and 1 cm³ of puree	13	Record, state, suggest
2	Biology: planning, height and recovery time after exercise	7	Plan
3	Chemistry: finding x in washing soda, Na₂CO₃·xH₂O, by heating	15	Record, calculate
4	Chemistry: tests to identify the ions in aqueous L	5	Record observations, state
5	Physics: spring constant from the time for 10 oscillations	13	Record, calculate, plot
6	Physics: temperature changes when hot and cold water are mixed	7	Record, calculate, suggest
	Total	60

How your own readings were marked: for every table you fill in from the experiment (1(a)(i), 3(a), 4(a), 5(a)(i) and 6(a)), the mark scheme says to compare against the supervisor’s results from your centre. It does not give fixed values, but it does build in checks that your numbers make sense, listed under each question below.

Question-by-question walkthrough

Question 1: catalase in celery puree, biology (13 marks)

Catalase in celery breaks down hydrogen peroxide into water and oxygen, and detergent turns the oxygen into foam. You measured the total height of the mixture and foam at 90 seconds, twice with 2 cm³ of puree and twice with 1 cm³ of puree plus 1 cm³ of water.

• Recording the heights (5 marks): one mark each for the 2 cm³ trial 1 result, the 2 cm³ trial 2 result and both 1 cm³ results; one for every height in mm, as the table heading asked; and one for all the 2 cm³ heights being greater than the 1 cm³ heights.
• Averages (1 mark): both correct, and the two averages had to be given to the same number of decimal places.
• Enzyme volume and height (1 mark): as the volume increases, the height increases. Both variables had to be comparative. “Positive correlation” was ignored, and “proportional” was not allowed unless your own results actually showed it.
• Enzyme volume and rate (1 mark): as the volume increases, the rate increases. “Proportional” was ignored here.
• Results at 4 °C (1 mark): lower heights. “Slower”, “smaller results” and “no increase in height” were ignored, because the answer had to describe the heights themselves.
• Why stir the puree (1 mark): so the celery cells (or the enzyme) are evenly spread, or so all the hydrogen peroxide meets the enzyme. “Evenly mix” was ignored because it just repeats the question, and so were “speeds up the reaction” and “stops the cells settling”.
• Why liquidise the celery (1 mark): to increase the surface area, or to break open the cells and release the enzyme. “Mixing” and “increases the rate” were ignored.
• Source of error and improvement (2 marks): a matched pair. The main routes were: the top of the foam is not level or the bubbles burst (1), so measure the volume of gas with a syringe and no detergent, or measure to the topmost part of the foam each time, or film it (1); the ruler’s zero is not at its end (1), so measure the foam only (1); the bottom of the boiling tube is curved (1), so use a measuring cylinder, beaker or conical flask, or measure the foam only (1). If neither mark was earned, one mark was available for parallax with a description of reading at eye level to the reading. “Eye level to the scale” and “levelling the foam with a ruler” were ignored.

Question 2: planning a recovery-time investigation, biology (7 marks)

You planned an investigation into whether a person’s height affects how long their pulse rate takes to return to resting after exercise. The mark scheme splits the 7 marks into five sections: one mark from each section, then any two more.

• Apparatus: a stop-watch or timer, a pulse meter (heart rate monitor, smart watch or ECG were accepted) or a tape measure or ruler, each with its use described in the method. “Counting manually” did not count as apparatus.
• Method: measure the resting pulse rate, exercise, then time how long the pulse takes to return to resting, for at least two heights.
• Measurements: the pulse before (and just after) exercise; the height of each person; the time to return to resting pulse; repeats at the same height to spot anomalies; at least five different heights.
• Control variables: the same sex, age or fitness for the people; the same time spent exercising, or the same named type of exercise. Weight was ignored, and so was “exercise to the same bpm”.
• Processing: plot recovery time against height; say how to read the graph (for example, a straight line through the origin means proportional); look at whether recovery time goes up, down or stays the same as height increases. A stated conclusion was ignored.

Question 3: finding x in washing soda, chemistry (15 marks)

You weighed an empty evaporating basin (M1), the basin with washing soda crystals (M2) and the basin with the dry powder after heating and cooling (M3). The paper told you to work on Question 4 while the basin cooled.

• Recording the masses (4 marks): the empty basin mass (1), all three masses (1), all to the same number of decimal places (1), and M3 between M1 and M2 (1).
• Mass of water (1 mark): M2 − M3, with significant figures matching your balance readings.
• Moles of water (1 mark): your mass of water ÷ 18.
• Mass of sodium carbonate (1 mark): M3 − M1, again matching your balance readings.
• Moles of sodium carbonate (1 mark): your mass ÷ 106.
• x (2 marks): moles of water ÷ moles of sodium carbonate (1), then rounded correctly to one significant figure (1). Each step allowed rounding or truncating and carried your own earlier answers forward.
• Mass of powder larger than expected (1 mark): water is still left in it, so heat to constant mass (heating again or for longer also scored). Both halves were needed.
• Making crystals from the solution (1 mark): heat to evaporate some of the water, or until the solution is saturated, and leave it to cool and crystallise. Heating or leaving to dryness was not allowed, and the word “crystallisation” alone was not enough.
• Chemical test for water (2 marks): anhydrous copper(II) sulfate, white to blue, or anhydrous cobalt(II) chloride, blue to pink. The colour mark depended on naming the right reagent.
• Why this method fails for JCO₃·yH₂O (1 mark): carbon dioxide is also given off, and it has mass, so the mass lost is not all water. “Carbon monoxide” was rejected and “CO₂ evaporates” was ignored.

Question 4: identifying the ions in L, chemistry (5 marks)

You did three tests on solution L and recorded what you saw.

• Observations (4 marks): with a few drops of sodium hydroxide, a white precipitate (1), which dissolved in excess to give a colourless solution (1); with nitric acid then silver nitrate, a yellow precipitate (1); with nitric acid then barium nitrate, a white precipitate (1).
• The ions (1 mark): zinc, iodide and sulfate (Zn²⁺, I⁻ and SO₄²⁻), carried forward from your observations. If you gave names and formulae, they had to match. “Iodine” was not allowed.

The qualitative analysis notes at the back of the paper list every one of these results.

Question 5: spring constant from oscillations, physics (13 marks)

You timed 10 oscillations of a mass hanger on a spring for total masses of 100 g to 500 g, worked out the time for one oscillation, T, and its square, and plotted T² against m.

• Recording t (4 marks): the first time present (1), all five present (1), all to 0.1 s (1) and the times increasing as the mass increases (1).
• T for each mass (1 mark): t ÷ 10, all correct, to any number of decimal places.
• T² (1 mark): all correct and to two decimal places, as the question asked.
• Plotting (2 marks): sensible linear scales with the points covering at least half the grid (1), and points plotted to within half a small square, with one error allowed (1).
• Line (1 mark): a straight line of best fit.
• Gradient (2 marks): a triangle using at least half the length of the line (1), and a gradient in the expected range of 0.0013 to 0.0017 (1).
• Spring constant (1 mark): k = 0.039 ÷ gradient, given to at least 2 significant figures in N/m. A gradient of 0.0015, for example, gives k = 26 N/m. Your own gradient was carried forward.
• Why 20 oscillations is better (1 mark): your reaction time is spread over more oscillations, so it has less effect. “Smaller percentage error” was also accepted. The word “accuracy” on its own, “20 takes longer” and “easier to measure” were all ignored.

Question 6: mixing hot and cold water, physics (7 marks)

You measured the temperature of 100 cm³ of cold water and 50 cm³ of hot water, mixed them and measured the temperature of the mixture.

• Recording temperatures (3 marks): the cold water temperature present (1), the mixture between the hot and cold temperatures (1), and all three to the nearest 0.5 °C (1).
• Temperature changes (1 mark): both changes correct, using the two subtractions printed in the question.
• Is the hot change double the cold change? (1 mark): a correct yes or no, backed by a calculation: double the cold water change, or halve the hot water change, and compare.
• Two mistakes with the thermometer (1 mark): the bulb is not fully under the water and the thermometer is touching the beaker. Both were needed for the mark. “It should be in the middle” was ignored.
• Reading straight from a 4 °C fridge sample (1 mark): a value above 4 °C but below the temperature of your cold water, and the reason: the thermometer has not finished falling, or it takes time to reach 4 °C.

Where the marks are on 0654/52

• Recording your own results carried 20 marks: the tables in 1(a)(i) (5), 3(a) (4), 4(a) (4), 5(a)(i) (4) and 6(a) (3). Units, decimal places and readings that make sense are all marked here.
• “Calculate” parts carried 13 marks: the averages in 1(a)(ii), the five washing soda steps in 3(b) (6), T, T², the gradient and k in Question 5 (5) and the temperature changes in 6(b).
• The plan carried 7 marks, all in Question 2.
• “Suggest” and “identify” parts carried 8 marks: 1(a)(v), 1(b)(i), 1(b)(ii), 1(b)(iii) (2), 3(c), 6(d) and 6(e).
• “State” parts carried 4 marks: 1(a)(iii), 1(a)(iv), 4(b) and 6(c).
• Plotting and drawing the graph carried 3 marks in 5(b)(i) and (ii).
• “Describe” parts carried 3 marks: making crystals in 3(d) and the test for water in 3(e) (2).
• “Explain” parts carried 2 marks: 3(f) and 5(c).

That is 20 + 13 + 7 + 8 + 4 + 3 + 3 + 2 = 60. Question 3 (15 marks) and Questions 1 and 5 (13 each) make up over two-thirds of the paper.

How to self-mark 0654/52 with the mark scheme

1. Learn the abbreviations first. A semicolon separates marking points, a slash shows alternatives, ALLOW means accept, IGNORE means the words neither gain nor lose credit, DO NOT ALLOW means reject, ORA means the reverse argument also scores and ecf means error carried forward.
2. Check your tables for internal sense. You can’t see the supervisor’s results, but you can check that the 2 cm³ heights beat the 1 cm³ ones, that M3 lies between M1 and M2, that t rises with m and that the mixture temperature lies between hot and cold.
3. Mark precision as its own point. Heights in mm, masses to the same number of decimal places, times to 0.1 s, T² to 2 decimal places and temperatures to the nearest 0.5 °C each carry a separate mark.
4. Redo the washing soda chain with ecf. If your mass of water was wrong, still give yourself the later marks if you used it correctly, and check x is rounded to one significant figure.
5. Check your gradient triangle. If it covers less than half the line, drop that mark; if your gradient falls outside 0.0013 to 0.0017, drop the second one.
6. Watch for answers on the ignore list. “Slower” in 1(a)(v), “evenly mix” in 1(b)(i), “weight” as a control in Question 2 and “accuracy” in 5(c) all scored nothing.
7. Mark the plan section by section. Tick one point in each of the five sections, then up to two extras, and stop at 7.

Sit 0654/52 as a timed mock

Paper 5 needs laboratory apparatus, so a full mock is best done in school. If you can only practise at home, answer the written parts of each question and use the fixed readings in Paper 62 for the tables. The paper allows 120 minutes for 60 marks. A workable plan:

Block	Marks	Time
Question 1 (catalase)	13	25 minutes
Question 2 (plan)	7	15 minutes
Questions 3 and 4 (start heating in Question 3, do Question 4 while the basin cools, then finish Question 3)	20	35 minutes
Question 5 (spring)	13	30 minutes
Question 6 (hot and cold water)	7	12 minutes
Check units, decimal places and the graph	–	3 minutes

Start the washing soda heating as early in its block as you can, so the cooling time isn’t wasted.

Other May/June 2026 0654 papers

• 0654 Paper 12 (Core Multiple Choice)
• 0654 Paper 22 (Extended Multiple Choice)
• 0654 Paper 32 (Core Theory)
• 0654 Paper 42 (Extended Theory)
• 0654 Paper 62 (Alternative to Practical)

Practise and download

• Download 0654/52 and its mark scheme on the Learning Portal →
• All 0654 May/June 2026 papers: overview and marking patterns
• Try a free IGCSE Co-ordinated Sciences quiz

Need help with a 0654 topic? Book a free trial lesson with an IGCSE Co-ordinated Sciences tutor →

Frequently asked questions

What topics were on 0654 Paper 52 May/June 2026? +

Six questions, two per science. Biology: catalase in celery puree (13 marks) and a plan linking a person's height to their recovery time after exercise (7). Chemistry: finding x in washing soda by heating (15) and identifying the ions in solution L (5). Physics: the spring constant from timed oscillations (13) and mixing hot and cold water (7).

How many marks is 0654/52 and how long is it? +

It is out of 60 marks and lasts 2 hours. Question 3, the washing soda experiment, is the biggest at 15 marks.

How were my own readings marked on 0654/52? +

Against the supervisor's results from your centre, not a fixed answer. The mark scheme also checks internal sense: the 2 cm³ celery heights had to be bigger than the 1 cm³ ones, M3 had to lie between M1 and M2, the oscillation times had to rise with mass and the mixture temperature had to lie between the hot and cold readings.

What ions were in solution L on 0654/52? +

Zinc, iodide and sulfate. The expected observations were a white precipitate with sodium hydroxide that dissolved in excess to give a colourless solution, a yellow precipitate with silver nitrate and a white precipitate with barium nitrate. Writing iodine instead of iodide was not allowed.

Is 0654/52 the same as 0654/62? +

They use the same six investigations, and the plan, the washing soda follow-up questions and the spring explanation are marked in the same way. Paper 6 gives you the readings as diagrams to record instead of asking you to take them, and adds questions on apparatus, balance use, flame tests, proportionality and safety.

Where can I download 0654/52 May/June 2026 and its mark scheme? +

Both are free to download and print on the Tutopiya Learning Portal, on the Cambridge IGCSE Co-ordinated Sciences 0654 past papers page.

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