If you're on Edexcel GCSE Combined Science (spec code 1SC0, often called the double award), there are 18 mandatory core practicals you need to know. Edexcel calls them "core practicals" rather than "required practicals", but the idea is the same: specific experiments defined in the specification that you have to carry out in class, and that the exam questions you about across all six papers.
This guide works through the full 18 in topic order, flags which Biology, Chemistry or Physics paper examines each one, and reconciles exactly what gets dropped if you're on Combined rather than the three separate 1BI0 Biology, 1CH0 Chemistry and 1PH0 Physics GCSEs. Different boards use different language for the same thing: Edexcel says "core practicals", AQA says "required practicals", OCR says "PAGs" (Practical Activity Groups). This article is Edexcel Combined only. If you're deciding between Combined and Triple, our Triple vs Double Science GCSE guide compares the routes. If you're on AQA Trilogy, use our AQA Combined Science required practicals guide instead.
This article was last checked against the Pearson Edexcel GCSE Combined Science (1SC0) specification on **14 October 2026**. Specifications and assessment detail change often, so cross-check the current Pearson specification page before relying on any specific detail.
Combined Science 1SC0 is the double-award qualification: you come out with two grades on one certificate (from 9-9 down to 1-1). If you're on the Triple route you sit three separate GCSEs with 24 core practicals in total: 8 Biology, 8 Chemistry, 8 Physics. The specifics are in the Combined vs Triple reconciliation section further down.
All 18 Edexcel core practicals
The table below lists every core practical on the 1SC0 spec in topic order, using Edexcel's own spec reference numbers. Edexcel marks each one as an entire specification point in italics inside the spec document, with the exact phrase "students must carry out all 18 of the mandatory core practicals listed below". Each paper is 1 hour 10 minutes, 60 marks, and worth 16.67% of the overall grade: Papers 1 and 2 cover Biology, 3 and 4 Chemistry, 5 and 6 Physics.
| Spec ref | Core practical | Science | Paper |
|---|---|---|---|
| 1.6 | Investigate biological specimens using microscopes, including magnification calculations and labelled scientific drawings | Biology | 1 or 2 |
| 1.10 | Investigate the effect of pH on enzyme activity | Biology | 1 or 2 |
| 1.16 | Investigate osmosis in potatoes | Biology | 1 or 2 |
| 6.5 | Investigate the effect of light intensity on the rate of photosynthesis | Biology | 2 |
| 8.11 | Investigate the rate of respiration in living organisms | Biology | 2 |
| 9.5 | Investigate the relationship between organisms and their environment using field-work techniques, including quadrats and belt transects | Biology | 2 |
| 2.11 | Investigate the composition of inks using simple distillation and paper chromatography | Chemistry | 3 |
| 3.6 | Investigate the change in pH on adding powdered calcium hydroxide or calcium oxide to a fixed volume of dilute hydrochloric acid | Chemistry | 3 |
| 3.17 | Investigate the preparation of pure, dry hydrated copper sulfate crystals, starting from copper oxide | Chemistry | 3 |
| 3.31 | Investigate the electrolysis of copper sulfate solution with inert electrodes and copper electrodes | Chemistry | 3 |
| 7.1 | Investigate the effects of changing conditions on rates of chemical reactions (gas production with HCl and marble chips; colour change with sodium thiosulfate and HCl) | Chemistry | 4 |
| 2.19 | Investigate the relationship between force, mass and acceleration by varying masses added to trolleys | Physics | 5 |
| 4.17 | Investigate the suitability of equipment to measure the speed, frequency and wavelength of a wave in a solid and a fluid | Physics | 5 |
| 5.9 | Investigate refraction in rectangular glass blocks in terms of the interaction of electromagnetic waves with matter | Physics | 5 |
| 10.17 | Construct electrical circuits to investigate potential difference, current and resistance for a resistor and filament lamp, and test series and parallel circuits | Physics | 6 |
| 14.3 | Investigate the densities of solids and liquids | Physics | 6 |
| 14.11 | Investigate the properties of water: determine the specific heat capacity of water and obtain a temperature–time graph for melting ice | Physics | 6 |
| 15.6 | Investigate the extension and work done when applying forces to a spring | Physics | 6 |
Count: six Biology, five Chemistry, seven Physics, totalling 18. Topic 1 (Key concepts) sits across both Biology papers; Topic 3 (Chemical changes) is the most practical-heavy Chemistry topic, with three core practicals all on Paper 3; in Physics, Topic 14 (Particle model) has two.
How practical skills are assessed
There's no separate practical exam for Edexcel Combined Science. Practical-skills questions are woven through all six written papers. They mostly fall under AO2 (apply knowledge and understanding, 40% of the overall grade) and AO3 (analyse information and ideas, interpret and evaluate, develop and improve experimental procedures, 20%). AO1 (demonstrate knowledge and understanding) is the remaining 40%.
Schools do carry an administrative obligation here. Centres must submit a Practical Science Statement by 15 April of the exam year, confirming to Pearson that students have carried out all 18 core practicals. Failing to submit is treated as malpractice. You won't need to think about this as a student, but it's why your teachers insist on completing every practical even when timetabling gets tight.
The exam questions themselves look identical in shape to the ones on any other board's practicals: describe the method, identify the variables, explain or evaluate the results, suggest improvements. The vocabulary Edexcel uses most often is "evaluate the method" (which expects a weakness plus a specific improvement) and "explain the pattern in the results" (which expects scientific reasoning, not just description).
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Combined vs Triple reconciliation
Combined (1SC0) drops six core practicals compared with the three separate Edexcel GCSEs. Triple totals: 8 Biology + 8 Chemistry + 8 Physics = 24. Combined totals: 6 + 5 + 7 = 18. The drops split unevenly: two Biology, three Chemistry, one Physics. Edexcel structures the drop around topics and sub-topics that only appear on the separate specs.
| Science | Dropped from Triple → Combined | Topic area dropped |
|---|---|---|
| Biology | 1.13B Use chemical reagents to identify starch, reducing sugars, proteins and fats (food tests) | Topic 1: Key concepts in biology |
| Biology | 5.18B Investigate the effects of antiseptics, antibiotics or plant extracts on microbial cultures | Topic 5: Health, disease and the development of medicines |
| Chemistry | 5.9C Carry out an accurate acid-alkali titration | Topic 5: Separate chemistry 1 |
| Chemistry | 9.6C Identify the ions in unknown salts using tests for the specified cations and anions | Topic 9: Separate chemistry 2 |
| Chemistry | 9.28C Investigate the combustion of alcohols (ethanol, propanol, butanol, pentanol) by measuring temperature rise in a known mass of water | Topic 9: Separate chemistry 2 |
| Physics | 5.19P Investigate how the nature of a surface affects the amount of thermal energy radiated or absorbed | Topic 5: Light and the electromagnetic spectrum |
If you're on Combined, do not revise titration, ion identification tests, combustion of alcohols, food tests, antiseptic/antibiotic microbial cultures or thermal-radiation surface investigations as core practicals: they aren't on your spec. Topics 5 (Separate chemistry 1), 9 (Separate chemistry 2) in Chemistry, plus the deeper content inside Biology Topics 1 and 5 and Physics Topic 5 are the "separate only" markers to watch for. Some of the underlying science (e.g. rates and equilibria, radiation and absorption) still features in Combined content, just not as a dedicated core practical.
Study tips for the 18 practicals
Reading through the method isn't enough. Core practicals test whether you can think like a scientist, not whether you can recite a recipe.
For each practical, write the method out from memory, then check it against your notes or a Cognito video. The steps you forgot are the ones that would have cost you marks. Pay attention to the small details Edexcel loves: controlling the volume of solution and temperature in osmosis, naming the specific buffer in enzyme experiments, calculating Rf as distance travelled by substance divided by distance travelled by solvent, blotting potato cylinders before weighing, using a respirometer with soda lime to absorb carbon dioxide in the respiration practical.
Practise drawing results tables with correct headings, units and decimal places. Edexcel frequently asks you to complete a partial table, and marks are awarded for correct units in the header, consistent decimal places, and the independent variable in the left-most column.
Sketch the graphs you'd expect for each practical. For light intensity vs rate of photosynthesis, a curve that rises and then plateaus. For force vs extension of a spring, a straight line through the origin until the limit of proportionality. For temperature–time graphs during a change of state, a flat plateau while the water melts or boils. Plotting correctly and labelling axes with units earns marks even if the explanation goes off track.
Work through past paper questions on each core practical. The wording Edexcel uses recycles year on year, and the mark schemes are the clearest guide to the exact phrases they want to see.
When the exam asks you to suggest an improvement, Edexcel wants a specific change plus the specific reason it works. "Repeat the experiment" is half an answer. "Repeat and calculate a mean to reduce the effect of random error" is a full answer.
How Cognito helps
Our Edexcel GCSE Combined Science courses cover all 18 core practicals through short video lessons, worked examples and exam-style questions. Each practical gets its own lesson that walks through the method, variables, results and the exam language. Jump into the Combined Science Biology course, the Combined Science Chemistry course or the Combined Science Physics course and track your progress through the whole spec.
If you want a wider revision framework, our how to revise for GCSE Science guide covers paper structure, timing and how to work core practicals into a term-by-term plan.
