Cambridge IGCSE Combined Science (0653) Past Papers & Examiner Tips (2026 Updated)
- William Cartwright
- Feb 23
- 24 min read
Updated: Mar 1
Here you will find the complete and latest Cambridge IGCSE Combined Science (0653) past papers, carefully organised to support focused and effective revision. Before downloading the papers papers, make sure you know whether you are entered for the Core or Extended tier, as this determines which exams you should practise. Most students take the Extended tier and will sit Papers 2, 4 and 6, while Core students will sit Papers 1, 3 and 5. If you are unsure, ask your teacher first.
We also strongly encourage you to read the examiner and teacher advice below first for Biology, Chemistry and Physics. Drawing on years of experience marking this subject, it explains how top students achieve the highest grades and the common errors that cause others to lose marks.
Cambridge IGCSE Combined Science (0653) March 2025 Past Papers – Question Papers & Mark Schemes
2025 Cambridge IGCSE Combined Science | Downloads | |
|---|---|---|
Cambridge IGCSE Combined Science (0653/12) March 2025 Paper 1 | ||
Cambridge IGCSE Combined Science (0653/22) March 2025 Paper 2 | ||
Cambridge IGCSE Combined Science (0653/32) March 2025 Paper 3 | ||
Cambridge IGCSE Combined Science (0653/42) March 2025 Paper 4 | ||
Cambridge IGCSE Combined Science (0653/52) March 2025 Paper 5 | ||
Cambridge IGCSE Combined Science (0653/62) March 2025 Paper 6 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) Extended March 2025?
For the Cambridge IGCSE Combined Science (0653) March 2025 Extended tier, the grade boundaries were the same across both Extended variants. For Variant 2 (Options BY and CY: Papers 22, 42 and 52 or 62), you needed 154 out of 200 for an A*, 129 for an A, 104 for a B, and 80 for a C. This means students generally needed around 77% for an A*, 65% for an A, just over 50% for a B, and around 40% for a C in this exam session.
Cambridge IGCSE Combined Science (0653) June 2025 Past Papers – Question Papers & Mark Schemes
2025 Cambridge IGCSE Combined Science | Downloads | |
Cambridge IGCSE Combined Science (0653/11) May June 2025 Paper 1 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/12) May June 2025 Paper 1 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/13) May June 2025 Paper 1 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/21) May June 2025 Paper 2 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/22) May June 2025 Paper 2 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/23) May June 2025 Paper 2 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/31) May June 2025 Paper 3 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/32) May June 2025 Paper 3 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/33) May June 2025 Paper 3 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/41) May June 2025 Paper 4 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/42) May June 2025 Paper 4 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/43) May June 2025 Paper 4 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/51) May June 2025 Paper 5 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/52) May June 2025 Paper 5 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/61) May June 2025 Paper 6 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/62) May June 2025 Paper 6 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/63) May June 2025 Paper 6 Variant 3 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) Extended June 2025?
For the Cambridge IGCSE Combined Science (0653) June 2025 Extended tier, the grade boundaries were slightly different depending on the variant. For Variant 1 (Option BX: Papers 21, 41 and 51), you needed 144 out of 200 for an A*, 121 for an A, 98 for a B, and 76 for a C. For Variant 2 (Option BY: Papers 22, 42 and 52), the requirements were slightly higher for the top grades, with 146 for an A*, 122 for an A, 98 for a B, and 75 for a C. For Variant 3 (Option CZ: Papers 23, 43 and 63), you needed 145 for an A*, 121 for an A, 97 for a B, and 74 for a C. Overall, this means that across all Extended variants, students typically needed around 145 marks for an A*, about 121–122 for an A, around 97–98 for a B, and mid-70s for a C.
Cambridge IGCSE Combined Science (0653) November 2025 Past Papers – Papers & Answers
2025 Cambridge IGCSE Combined Science | Downloads | |
Cambridge IGCSE Combined Science (0653/11) October November 2025 Paper 1 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/12) October November 2025 Paper 1 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/13) October November 2025 Paper 1 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/21) October November 2025 Paper 2 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/22) October November 2025 Paper 2 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/23) October November 2025 Paper 2 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/31) October November 2025 Paper 3 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/32) October November 2025 Paper 3 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/33) October November 2025 Paper 3 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/41) October November 2025 Paper 4 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/42) October November 2025 Paper 4 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/43) October November 2025 Paper 4 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/51) October November 2025 Paper 5 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/52) October November 2025 Paper 5 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/61) October November 2025 Paper 6 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/62) October November 2025 Paper 6 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/63) October November 2025 Paper 6 Variant 3 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) Extended November 2025?
For the Cambridge IGCSE Combined Science (0653) November 2025 Extended tier, the grade boundaries varied slightly depending on the variant. For Variant 1 (Option BX: Papers 21, 41 and 51), you needed 151 out of 200 for an A*, 127 for an A, 103 for a B, and 80 for a C. For Variant 2 (Option BY: Papers 22, 42 and 52), the thresholds were lower, with 151 for an A*, 125 for an A, 99 for a B, and 74 for a C. For Variant 3 (Option CZ: Papers 23, 43 and 63), you needed 150 for an A*, 126 for an A, 102 for a B, and 78 for a C. Overall, this means students typically needed around 150–152 marks for an A*, 125–128 for an A, 99–104 for a B, and mid-to-high 70s for a C.
Cambridge IGCSE Combined Science (0653) March 2024 Past Papers – Question Papers & Mark Schemes
2024 Cambridge IGCSE Combined Science | Downloads | |
Cambridge IGCSE Combined Science (0653/12) March 2024 Paper 1 | ||
Cambridge IGCSE Combined Science (0653/22) March 2024 Paper 2 | ||
Cambridge IGCSE Combined Science (0653/32) March 2024 Paper 3 | ||
Cambridge IGCSE Combined Science (0653/42) March 2024 Paper 4 | ||
Cambridge IGCSE Combined Science (0653/52) March 2024 Paper 5 | ||
Cambridge IGCSE Combined Science (0653/62) March 2024 Paper 6 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) Extended March 2024?”
For the Cambridge IGCSE Combined Science (0653) March 2024 Extended tier, the grade boundaries were the same for both Extended variants. For Variant 2 (Options BY and CY: Papers 22, 42 and 52 or 62), you needed 156 out of 200 for an A*, 131 for an A, 106 for a B, and 82 for a C. This means students generally needed around 78% for an A*, 65% for an A, just over 50% for a B, and about 40% for a C.
Cambridge IGCSE Combined Science (0653) June 2024 Past Papers – Question Papers & Mark Schemes
2024 Cambridge IGCSE Combined Science | Downloads | |
Cambridge IGCSE Combined Science (0653/11) May June 2024 Paper 1 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/12) May June 2024 Paper 1 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/13) May June 2024 Paper 1 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/21) May June 2024 Paper 2 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/22) May June 2024 Paper 2 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/23) May June 2024 Paper 2 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/31) May June 2024 Paper 3 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/32) May June 2024 Paper 3 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/33) May June 2024 Paper 3 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/41) May June 2024 Paper 4 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/42) May June 2024 Paper 4 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/43) May June 2024 Paper 4 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/51) May June 2024 Paper 5 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/52) May June 2024 Paper 5 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/61) May June 2024 Paper 6 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/62) May June 2024 Paper 6 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/63) May June 2024 Paper 6 Variant 3 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) Extended June 2024?
For the Cambridge IGCSE Combined Science (0653) June 2024 Extended tier, the grade boundaries varied slightly across the different variants. For Variant 1 (Option BX: Papers 21, 41 and 51), you needed 149 out of 200 for an A*, 125 for an A, 101 for a B, and 77 for a C. For Variant 2 (Option BY: Papers 22, 42 and 52), the thresholds were 148 for an A*, 124 for an A, 100 for a B, and 77 for a C. For Variant 3 (Option CZ: Papers 23, 43 and 63), the marks were slightly higher, with 150 needed for an A*, 126 for an A, 102 for a B, and 79 for a C. Overall, this means students typically needed around 148–150 marks for an A*, 124–126 for an A, 100–102 for a B, and high-70s for a C.
Cambridge IGCSE Combined Science (0653) November 2024 Past Papers – Papers & Answers
2024 Cambridge IGCSE Combined Science | Downloads | |
Cambridge IGCSE Combined Science (0653/11) October November 2024 Paper 1 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/12) October November 2024 Paper 1 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/13) October November 2024 Paper 1 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/21) October November 2024 Paper 2 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/22) October November 2024 Paper 2 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/23) October November 2024 Paper 2 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/31) October November 2024 Paper 3 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/32) October November 2024 Paper 3 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/33) October November 2024 Paper 3 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/41) October November 2024 Paper 4 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/42) October November 2024 Paper 4 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/43) October November 2024 Paper 4 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/51) October November 2024 Paper 5 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/52) October November 2024 Paper 5 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/53) October November 2024 Paper 5 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/61) October November 2024 Paper 6 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/62) October November 2024 Paper 6 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/63) October November 2024 Paper 6 Variant 3 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) November 2024 Extended?
For the Cambridge IGCSE Combined Science (0653) November 2024 Extended tier, the grade boundaries varied slightly depending on the variant. For Variant 1 (Option BX: Papers 21, 41 and 51), you needed 152 out of 200 for an A*, 128 for an A, 104 for a B, and 80 for a C. For Variant 2 (Option BY: Papers 22, 42 and 52), the thresholds were higher, with 155 for an A*, 131 for an A, 107 for a B, and 83 for a C. For Variant 3 (Option CZ: Papers 23, 43 and 63), you needed 151 for an A*, 127 for an A, 103 for a B, and 79 for a C. Overall, this means students typically needed around 151–155 marks for an A*, 127–131 for an A, 103–107 for a B, and around 79–83 for a C, depending on the variant taken in this exam session.
Cambridge IGCSE Combined Science (0653) March 2023 Past Papers – Question Papers & Mark Schemes
2023 Cambridge IGCSE Combined Science | Downloads | |
Cambridge IGCSE Combined Science (0653/12) March 2023 Paper 1 | ||
Cambridge IGCSE Combined Science (0653/22) March 2023 Paper 2 | ||
Cambridge IGCSE Combined Science (0653/32) March 2023 Paper 3 | ||
Cambridge IGCSE Combined Science (0653/42) March 2023 Paper 4 | ||
Cambridge IGCSE Combined Science (0653/52) March 2023 Paper 5 | ||
Cambridge IGCSE Combined Science (0653/62) March 2023 Paper 6 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) Extended March 2023?
For the Cambridge IGCSE Combined Science (0653) March 2023 Extended tier, the grade boundaries were the same for both Extended variants. For Variant 2 (Options BY and CY: Papers 22, 42 and 52 or 62), you needed 147 out of 200 for an A*, 124 for an A, 101 for a B, and 79 for a C. This means students generally needed around 74% for an A*, 62% for an A, just over 50% for a B, and around 40% for a C.
Cambridge IGCSE Combined Science (0653) May/June 2023 Past Papers – Papers & Answers
2023 Cambridge IGCSE Combined Science | Downloads | |
Cambridge IGCSE Combined Science (0653/11) May June 2023 Paper 1 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/12) May June 2023 Paper 1 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/13) May June 2023 Paper 1 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/21) May June 2023 Paper 2 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/22) May June 2023 Paper 2 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/23) May June 2023 Paper 2 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/31) May June 2023 Paper 3 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/32) May June 2023 Paper 3 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/33) May June 2023 Paper 3 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/41) May June 2023 Paper 4 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/42) May June 2023 Paper 4 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/43) May June 2023 Paper 4 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/51) May June 2023 Paper 5 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/52) May June 2023 Paper 5 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/61) May June 2023 Paper 6 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/62) May June 2023 Paper 6 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/63) May June 2023 Paper 6 Variant 3 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) Extended June 2023?
For the Cambridge IGCSE Combined Science (0653) June 2023 Extended tier, the grade boundaries varied slightly across the different variants. For Variant 1 (Option BX: Papers 21, 41 and 51), you needed 144 out of 200 for an A*, 120 for an A, 96 for a B, and 73 for a C. For Variant 2 (Option BY: Papers 22, 42 and 52), the thresholds were slightly higher, with 147 for an A*, 123 for an A, 99 for a B, and 75 for a C. For Variant 3 (Option CZ: Papers 23, 43 and 63), you needed 144 for an A*, 120 for an A, 96 for a B, and 73 for a C. Overall, this means students typically needed around 144–147 marks for an A*, 120–124 for an A, 96–99 for a B, and low-to-mid 70s for a C.
Cambridge IGCSE Combined Science (0653) November 2023 Past Papers – Papers & Answers
2023 Cambridge IGCSE Combined Science | Downloads | |
Cambridge IGCSE Combined Science (0653/11) October November 2023 Paper 1 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/12) October November 2023 Paper 1 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/13) October November 2023 Paper 1 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/21) October November 2023 Paper 2 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/22) October November 2023 Paper 2 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/23) October November 2023 Paper 2 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/31) October November 2023 Paper 3 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/32) October November 2023 Paper 3 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/33) October November 2023 Paper 3 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/41) October November 2023 Paper 4 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/42) October November 2023 Paper 4 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/43) October November 2023 Paper 4 Variant 3 | ||
Cambridge IGCSE Combined Science (0653/51) October November 2023 Paper 5 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/61) October November 2023 Paper 6 Variant 1 | ||
Cambridge IGCSE Combined Science (0653/62) October November 2023 Paper 6 Variant 2 | ||
Cambridge IGCSE Combined Science (0653/63) October November 2023 Paper 6 Variant 3 | ||
What marks are needed for A*, A, B and C in Cambridge IGCSE Combined Science (0653) Extended November 2023?
For the Cambridge IGCSE Combined Science (0653) November 2023 Extended tier, the grade boundaries varied slightly depending on the variant. For Variant 1 (Option BX: Papers 21, 41 and 51), you needed 148 out of 200 for an A*, 124 for an A, 100 for a B, and 77 for a C. For Variant 2 (Option BY: Papers 22, 42 and 52), the thresholds were slightly higher, with 151 for an A*, 126 for an A, 101 for a B, and 77 for a C. For Variant 3 (Option CZ: Papers 23, 43 and 63), the requirements were 153 for an A*, 128 for an A, 103 for a B, and 78 for a C. Overall, this means students typically needed around 148–153 marks for an A*, 124–128 for an A, 100–103 for a B, and around 77–78 for a C.
What Cambridge IGCSE Combined Science Chemistry Examiners Wish Every Student Knew
Before you start revising, it’s essential to understand the mistakes that cost students the most marks in Cambridge IGCSE Combined Science. The guidance below is based on official examiner reports and our teachers with years of teaching experience, highlighting the key issues that appear in Biology, Chemistry and Physics every exam series.
1. Cell Structures and Their Roles
Two slip-ups show up here with noticeable regularity among IGCSE students. The first is placing photosynthesis in the vacuole rather than the chloroplast — a classic mix-up. The second, and slightly subtler, is confusing the specific structure where photosynthesis happens (the chloroplast) with the tissue type it sits within (the palisade mesophyll). Candidates who muddle these two are often closer to understanding than their answer suggests, but the distinction matters.
Photosynthesis happens in the chloroplasts, which are organelles found in the cytoplasm. The large central vacuole has a different job entirely — it pushes the cytoplasm outward, keeping the plant cell firm and providing structural support. These are two very different structures doing two very different things, and it's worth reinforcing that clearly in any feedback you give.
2. Human Development and Gamete Characteristics
There are actually a few distinct errors bundled into this topic, which is part of why it causes so much trouble. Candidates often can't correctly sequence what happens after fertilization, and there's also real confusion about which gamete has which features — flagella, energy stores, and so on. Some think egg cells have flagella; others believe sperm cells are the ones carrying an energy store.
The developmental sequence is worth drilling: fertilized ovum → zygote → embryo (a ball of cells). On the gamete side, it's the egg cell that carries the energy store, and it's the sperm cell that has the flagellum for motility. These are straightforward facts, but candidates clearly need to encounter them repeatedly before they stick.
3. Heart Anatomy and Blood Vessel Function
Two distinct errors tend to cluster around this topic. The first is conflating the septum with a valve — candidates describe one when they clearly mean the other. The second is assuming the pulmonary artery carries oxygenated blood, likely because it leaves the heart and the word "pulmonary" sounds important enough to be associated with oxygen.
The distinction is worth making explicit: valves are about direction — they ensure blood can only flow one way. The septum is about separation — it's the wall that keeps oxygenated and deoxygenated blood from mixing. As for the pulmonary artery, it's the exception candidates need to actively remember: it carries deoxygenated blood away from the heart to the lungs, which runs counter to the assumption that arteries always carry oxygenated blood.
4. Plant Nutrition and Reproduction
In nutrition questions, candidates often get halfway there — they'll correctly state that magnesium deficiency leads to less chlorophyll — but then stop short of completing the chain of reasoning. The link to reduced photosynthesis and, consequently, a lower growth rate is almost always missing. In reproduction, the stigma/anther mix-up is a dependable one: pollen production gets placed in the stigma far more often than it should.
For nutrition, it's about pushing candidates to follow the logic all the way through: less magnesium → less chlorophyll → less photosynthesis → slower growth. Each step follows naturally from the last, and full marks should reflect that full chain. For reproduction, the roles are straightforward but easily swapped: the anther produces pollen, and the stigma receives it. A simple mnemonic or paired definition is often all it takes to make this stick.
5. Misapplying Transport Mechanisms — Osmosis vs. Diffusion
When describing transpiration, candidates regularly reach for the word "osmosis" to describe water leaving the leaf. It's an understandable instinct — water is moving, osmosis involves water — but it's scientifically wrong, and it suggests a surface-level understanding of both processes.
The key distinction is the state of matter. Osmosis is strictly a liquid-medium process — it describes the movement of water molecules across a partially permeable membrane. What happens at the stomata during transpiration is diffusion: water vapour, a gas, moving from an area of higher concentration inside the leaf to lower concentration outside. If candidates can anchor each term to its medium (liquid vs. gas), the confusion tends to resolve itself.
The Most Common Physics Mistakes in Cambridge IGCSE Combined Science (According to Examiners)
This advice is taken from the feedback from Cambridge IGCSE Combined Science examiners and our teachers and are the mistakes students repeat every year. Our teachers have spent hours compiling the most important points, so reading this first could make a real difference to your final grade.
1. Misunderstanding the Variables for Work Done
This one is surprisingly persistent — candidates consistently believe that the time taken to complete a task has some bearing on the work done. It makes intuitive sense that doing something slowly versus quickly would change things, which is probably why the misconception is so sticky.
Work done depends on exactly two things: the force applied and the distance moved in the direction of that force. Time plays no role whatsoever in the work done calculation. Where time does matter is power — power is simply work done divided by time. If candidates can keep those two equations clearly separated in their minds, this error largely disappears.
2. Energy Calculations and Unit Conversions
Two separate issues tend to appear here, and both are worth flagging consistently. The first is a calculation error in kinetic energy questions: rather than squaring each speed individually, candidates subtract the initial speed from the final speed and then square the result — which is mathematically incorrect and will always give the wrong answer. The second is a unit conversion problem that shows up across energy topics more broadly: candidates leave mass in grams instead of converting to kilograms, or forget to convert minutes into seconds, and then plug those unconverted values straight into the equation.
For kinetic energy changes, the habit to build is squaring first, subtracting after — always. For units, the rule is equally simple but needs to become automatic: convert everything to SI units before touching the equation. Grams to kilograms, centimetres to metres, nanometres to metres, minutes to seconds — all of it, done first, every time. Candidates who make this a non-negotiable step in their working will avoid a category of error that costs marks across multiple topics.
3. Confusing Nuclear Fusion and Fission
These two terms get swapped so regularly that it's almost worth anticipating it as a default. Candidates either reverse the definitions outright or, when asked about energy production in stars, reach for the wrong process entirely.
The simplest anchor is the words themselves. Fission — think splitting. Fusion — think joining. In stars, it's fusion: hydrogen nuclei join together to form helium, releasing enormous amounts of energy in the process. It's also worth reminding candidates to write nuclear fusion in full rather than just "fusion" — the extra word signals precision and avoids any ambiguity in their answer.
4. Force, Pressure, and Orientation
Two separate errors cluster around this topic. The first is a conceptual one: candidates suggest that rotating an object — say, tipping a block onto a different face — changes the force it exerts. It doesn't, and the reasoning behind why not is something candidates clearly haven't internalised. The second is a unit mismatch that's easy to overlook when marking: candidates correctly calculate pressure but then write the unit as Pa, despite having used N and cm² in their working — which makes the unit label flat-out wrong.
On the conceptual side, the key insight is this — rotating an object changes the contact area, not the force. The weight of the object stays constant regardless of orientation; it's the pressure that changes as a result of the area changing, via P = F/A. On units, Pa is specifically defined as N/m² — if the area used in the calculation was in cm², then the correct unit for the answer is N/cm², full stop. It's a small detail, but one the mark scheme will penalise, so it's worth flagging clearly in any feedback.
5. Thermal Conduction and Radiation
Two misconceptions sit side by side here, and both are worth addressing directly. On conduction, candidates frequently describe thermal energy in metals as being transferred by vibrating atoms passing energy to their neighbours — which is how conduction works in non-metals, but not in metals. On radiation, there's a logical-sounding but incorrect assumption at play: candidates reason that because black/dull surfaces are the opposite of white/shiny ones, a good emitter must be a poor absorber. It feels consistent, but it's wrong.
In metals, conduction is driven primarily by free electrons moving through the structure — this is what makes metals such efficient conductors compared to non-metals. The vibrating-atoms model simply doesn't apply here. On radiation, candidates need to hold onto a fact that cuts against their intuition: good emitters are also good absorbers. Black and dull surfaces sit at one end of both scales simultaneously; white and shiny surfaces sit at the other end of both. There's no trade-off between the two properties.
6. Electrical Symbols and the Role of Fuses
Symbol misidentification is a recurring issue — motors get mistaken for meters, heaters for fuses — and it's the kind of error that suggests candidates haven't spent enough time with the standard symbol list. Separately, there's a meaningful conceptual error around fuses: candidates describe them as "controlling" or "supplying" current, which fundamentally misrepresents what a fuse actually does.
On symbols, there's no shortcut — candidates need to know the full syllabus list, and regular low-stakes testing on them is probably the most effective remedy. On fuses, the language matters: a fuse is a safety device, not a control mechanism. Its job is to melt and break the circuit if the current gets too high, protecting the appliance and wiring from damage. That's it. Any answer that frames it as regulating or providing current should not be awarded the mark.
What Cambridge IGCSE Combined Science Chemistry Examiners Wish You Knew Before the Exam
This advice is taken from the feedback from Cambridge IGCSE Combined Science examiners and our teachers and are the mistakes students repeat every year. Our teachers have spent hours compiling the most important points, so reading this first could make a real difference to your final grade.
1. Imprecise Qualitative Observations
Vagueness is the dominant issue here, and it costs marks more often than it should. Descriptions like "cloudy" or "milky" don't cut it at this level, and "clear" is used routinely when candidates actually mean "colourless" — a distinction that matters more than many realise. There's also a consistent tendency to give only half the observation: a colour without a state, or a state without a colour.
The habit to build is simple — always give both a colour and a state. "Blue precipitate." "Colourless solution." "Orange solid." That's the standard, and anything less is likely to drop marks. On the clear/colourless issue: "clear" means you can see through something, which is true of a blue copper sulfate solution just as much as it is of water. What candidates mean when they write "clear" is almost always colourless — no colour present at all. It's a small word, but examiners will notice the difference.
2. Particles in Conductivity and Electrolysis
There's genuine conceptual confusion here across two related but distinct ideas. First, candidates frequently attribute conductivity in ionic substances to atoms or molecules moving, rather than ions — showing that the underlying model hasn't quite landed. Second, and very reliably, candidates name the wrong thing at the electrode: writing "bromide is produced" rather than "bromine", conflating the ion in solution with the element it becomes.
The distinction is worth making explicit and repeatedly: in molten or aqueous ionic substances, it is mobile ions that carry the current — not atoms, not molecules. In metals and alloys, the charge carriers are free electrons. These are two separate mechanisms and candidates need to keep them clearly separated. At the electrode, the language must shift: bromide is what goes in; bromine is what comes out. The same logic applies across all electrolysis products — always name the element formed, not the ion it came from.
3. Specificity in Chemical Composition
Vague or inaccurate answers about molecular building blocks are a consistent issue. The most common offender is the composition of fats — candidates write "fatty acids and glucose" often enough that it's clearly a widespread misconception rather than a one-off slip. Similarly, when enzymes come up, amylase gets paired with "carbohydrates" as a catch-all rather than its specific substrate.
Precision is everything in biological chemistry, and the mark scheme will reflect that. Fats are made from fatty acids and glycerol — glucose has no role in that molecule and shouldn't appear in the answer. For amylase, the specific language required is that it breaks down starch into maltose or glucose — not carbohydrates broadly. Candidates who reach for the general category when the specific term exists are almost always leaving marks on the table.
4. Explanations for Boiling Points
When asked to explain why a substance like potassium nitrate has a high boiling point, candidates frequently fall back on surface-level reasoning — "it contains a metal" or "it's a compound rather than an element." These answers identify a feature of the substance without actually explaining anything about its physical behaviour.
Boiling point questions are asking about forces between particles, not the identity of the particles themselves. A complete answer needs to address the strength of the attractive forces holding particles together and the amount of energy required to overcome them and separate the particles. Whether something contains a metal or is a compound is beside the point — what matters is the nature and strength of the interactions between its particles. Any answer that doesn't engage with that reasoning shouldn't receive full marks.
5. Confusing Observations with Inferences
This is one of the most reliable errors across the whole papers, and it's worth applying consistently when marking. When asked for an observation, candidates name the product instead of describing what they actually see — "carbon dioxide is produced" rather than anything about the physical evidence in front of them. It's an inference dressed up as an observation, and it shouldn't score the mark.
An observation is strictly what can be seen, heard, or felt — nothing more. For gas production, the expected language is effervescence, fizzing, or bubbles forming — not the name of the gas. For a dissolving solid, candidates should describe the solid disappearingor decreasing in size, not simply state that a reaction occurred. If the answer could only be known through prior knowledge rather than direct sensory experience, it's an inference, not an observation. That's a useful rule of thumb to share with candidates when giving feedback.
6. Hydrocarbons and Saturation
Two distinct confusions show up here. The word "unsaturated" carries a different meaning in everyday chemistry contexts — a solution that can dissolve more solute — and candidates frequently import that meaning into organic chemistry questions where it has no place. Separately, many candidates don't hold a tight enough definition of a hydrocarbon, and will include molecules containing oxygen or nitrogen without realising that disqualifies them entirely.
In organic chemistry, the definitions are non-negotiable: saturated means single bonds only; unsaturated means the molecule contains at least one C=C double bond. The solution chemistry meaning of unsaturated is irrelevant here and should never appear in this context. On hydrocarbons, the definition must be airtight — carbon and hydrogen atoms only. Any other element present and it's no longer a hydrocarbon, full stop. Candidates who can state these definitions precisely, without importing meanings from other contexts, are showing exactly the kind of conceptual clarity that earns marks.
Can You Practice With Past Papers For The 2026 Cambridge IGCSE Combined Science, And What Do You Need To Watch Out For?
You can still use past papers, but with caution — there are several significant changes that make older papers prior to 2025 different from the 2026 format. Here is what to be aware of:
Structure: The entire syllabus has been reorganised to align more closely with the separate IGCSE sciences (Biology 0610, Chemistry 0620, Physics 0625), so older Combined Science-specific notes may be outdated.
Assessment: The biggest differences are in Papers 5 and 6. Both the Practical Test (Paper 5) and the Alternative to Practical (Paper 6) now include a compulsory Planning question worth 6–7 marks, where you are asked to design an experiment from scratch — this will not appear in older past papers. Paper 5 has also been updated to 40 marks with a duration of 1 hour 15 minutes. There is also a stronger emphasis on transferable skills like data handling and applying the scientific method across all three disciplines.
Content: Three subject-specific refinements are worth noting. In Chemistry, expect a heavier focus on the Mole concept and stoichiometry. In Biology, precise terminology is now strictly required — for example, "water potential" must be used instead of just "concentration" when discussing osmosis. In Physics, omitting formulae or units in calculation working will now be more strictly penalised.
That said, the core scientific content across Biology, Chemistry, and Physics is largely the same, so past papers are still excellent for practising the majority of questions. Just keep the changes in mind — particularly for Papers 5 and 6 where the Planning question is new — and you will get a lot of value out of them.
Comments