In short
Edexcel GCSE Biology (1BI0) has 8 mandatory core practicals. Edexcel GCSE Combined Science (1SC0) has 6 of them for biology: the two Biology-only ones are food tests (1.13B) and antiseptics, antibiotics or plant extracts (5.18B). Your school confirms you did them, and the written papers ask questions about them. Each one below links to a free full practical sheet.
Pearson Edexcel GCSE (9-1) Biology (1BI0) has eight mandatory core practicals. Edexcel GCSE (9-1) Combined Science (1SC0) uses six of them for its biology part. The two that are only in GCSE Biology are the food tests (spec point 1.13B) and the effect of antiseptics, antibiotics or plant extracts on microbes (5.18B). In the Edexcel specification, any point with a B in its number is Biology only.
Nobody marks you while you do them. Your school sends Pearson a Practical Science Statement by 15 April of your exam year to confirm you did them all, and the written papers then ask about methods, variables, data and improvements. Below is the full list, then each practical in turn. Every one links to our free Edexcel GCSE Biology practical sheets.
Edexcel GCSE Biology core practicals list (summary table)
| Spec point | Core practical | What you measure | Paper | Combined Science? |
|---|---|---|---|---|
| 1.6 | Using a light microscope | Image size, then magnification or real size | 1 or 2 | Yes |
| 1.10 | The effect of pH on enzyme activity | Time for amylase to break down starch | 1 or 2 | Yes |
| 1.13B | Food tests | Colour changes (qualitative) | 1 or 2 | Biology only |
| 1.16 | Osmosis in potatoes | Percentage change in mass | 1 or 2 | Yes |
| 5.18B | Antiseptics, antibiotics and plant extracts | Area of the clear zone (πr²) | 1 | Biology only |
| 6.5 | Light intensity and photosynthesis | Rate of oxygen production | 2 | Yes |
| 8.11 | Rate of respiration | Distance the liquid moves in a respirometer | 2 | Yes |
| 9.5 | Quadrats and belt transects | Number of plants per quadrat and an abiotic factor | 2 | Yes |
Topic 1 is common to both papers, so its four practicals can come up on either. Topic 5 is on Paper 1; Topics 6, 8 and 9 are on Paper 2.
Which core practicals are in Edexcel Combined Science biology?
Combined Science has 18 core practicals across the three sciences. The six biology ones are microscopy (1.6), pH and enzymes (1.10), osmosis (1.16), photosynthesis (6.5), respiration (8.11) and quadrats and belt transects (9.5). Our Edexcel Combined Science practicals page has the same sheets without the two Biology-only ones.
The 8 Edexcel biology core practicals, one by one
Core practical 1.6: Investigating specimens with a light microscope
Aim: Investigate biological specimens using microscopes, including magnification calculations and labelled scientific drawings from observations (the spec wording).
Method in brief: Mount a thin layer of onion epidermis in water, stain with iodine and lower a coverslip at an angle. Focus on the lowest-power objective with the coarse knob, then sharpen with the fine knob. Draw the cells and calculate magnification or real size.
Key variables: None, because this is a skills practical. You use ==magnification = image size ÷ real size== and need to handle milli, micro and nano units (spec point 1.5).
What exam questions ask: total magnification from the eyepiece and objective lenses, real size or magnification from a drawing (for example, a 64 mm drawing of a 160 µm cell is ×400), why you start on low power, which focus knob to use on high power, and what makes a good scientific drawing.
Convert to the same unit before dividing: 64 mm is 64 000 µm. Magnification has no unit, so write ×400, not 400 mm.
Full method, results and exam-style questions: microscopy practical sheet. Notes: Microscopy and measuring cells. Combined Science students can use the Combined version.
Core practical 1.10: The effect of pH on enzyme activity
Aim: Find how pH affects the time amylase takes to break down starch, and find the optimum pH.
Method in brief: Mix starch with a buffer, warm it, add amylase and start timing. Every 10 seconds, drop a sample onto iodine on a spotting tile until the iodine stays orange-brown. The specification calls this continuous sampling and keeps the temperature steady with a Bunsen burner and a beaker of water.
Key variables: Independent: pH. Dependent: time for the starch to be broken down. Control: temperature, and the volume and concentration of the amylase and starch. Spec point 1.11 adds the rate calculation, ==rate = 1 ÷ time==.
What exam questions ask: why a buffer is used, why the solutions are warmed before mixing, how you know all the starch has gone, a rate calculation (a mean time of 75 s gives 0.013 s⁻¹), reading the optimum pH from a table, and why the reaction is slow at pH 4.
Writing that a buffer "makes the pH 7". A buffer keeps the pH constant at its own value. At the wrong pH the active site changes shape and the enzyme is denatured, not "killed".
Full method: pH and enzyme activity practical sheet. Notes: Enzyme action and activity. Combined Science: Combined version.
Core practical 1.13B: Food tests (Biology only)
Aim: Use chemical reagents to identify starch, reducing sugars, proteins and fats.
Method in brief: Starch: iodine solution. Reducing sugars: Benedict's solution, heated in a water bath. Protein: the Biuret test (potassium hydroxide, then copper sulfate). Fats: the emulsion test with ethanol, then water.
Key variables: None, because the tests are qualitative: they show whether a molecule is there, not how much. A distilled-water tube makes a useful control.
What exam questions ask: the reagent and the positive result for each test, why Benedict's tubes go in a water bath and not over a flame, identifying the molecules in two foods from a results table, ethanol safety, and a 6-mark question on testing one food for all four molecules.
Always give both colours: iodine orange-brown to blue-black, Benedict's blue to brick-red (through green, yellow and orange), Biuret blue to purple. The fat test gives a cloudy white emulsion.
Full method: food tests practical sheet. Notes: Enzymes in the body, food tests and energy. This one is not in Combined Science.
Core practical 1.16: Osmosis in potatoes
Aim: Find how the concentration of sucrose solution affects the mass of potato tissue, and use this to estimate the concentration inside the potato cells.
Method in brief: Cut equal potato cylinders with a cork borer, blot and weigh them, and leave each in a different sucrose concentration for the same time. Blot, reweigh and work out the percentage change in mass.
Key variables: Independent: concentration of sucrose solution. Dependent: percentage change in mass (spec point 1.17). Control: potato type, cylinder size, volume of solution, time and temperature.
What exam questions ask: why the cylinders are blotted, why percentage change is used instead of change in mass, a calculation (2.60 g to 2.34 g is −10%), why mass rises in pure water, and reading the cell concentration off a graph where the line crosses zero.
Saying "the solution moves into the potato". It is water that moves, by osmosis, across a partially permeable membrane from a dilute solution to a more concentrated one.
Full method: osmosis in potatoes practical sheet. Notes: Transport in cells. Combined Science: Combined version.
Core practical 5.18B: Antiseptics, antibiotics or plant extracts on microbes (Biology only)
Aim: Investigate the effects of antiseptics, antibiotics or plant extracts on microbial cultures.
Method in brief: Using aseptic technique with a Bunsen burner (a specification requirement), spread bacteria on a pre-poured agar plate. Add discs soaked in each substance plus a sterile-water control disc. Tape the lid without fully sealing it, incubate at 25 °C and measure each clear zone.
Key variables: Independent: the substance on the disc. Dependent: the size of the clear zone, turned into an area with πr² (spec point 5.19B). Control: the bacteria, the agar, the disc size, and the incubation temperature and time.
What exam questions ask: why there is a sterile-water disc, why plates are incubated at 25 °C and not 37 °C, why the lid is not fully sealed, an area calculation (a 16 mm diameter gives about 201 mm²), comparing substances from a table, and a 6-mark question on aseptic technique.
The formula needs the radius. Halve the diameter first: 16 mm becomes 8 mm, and 3.14 × 8² = 201 mm² (to 3 significant figures).
Full method: antimicrobials practical sheet. Notes: Antibiotics, microbial culture and medicines. This one is not in Combined Science.
Core practical 6.5: Light intensity and the rate of photosynthesis
Aim: Investigate the effect of light intensity on the rate of photosynthesis.
Method in brief: The specification uses algal balls (or similar) at different distances from a light source. Many schools use pondweed instead and count oxygen bubbles per minute at each lamp distance, letting the plant adjust before each reading.
Key variables: Independent: light intensity, changed by moving the lamp. Dependent: the rate of photosynthesis (for example, bubbles per minute). Control: temperature (a heat shield or an LED lamp), carbon dioxide (the same sodium hydrogencarbonate solution) and the same plant.
What exam questions ask: why a heat shield and sodium hydrogencarbonate are used, a mean bubble count, describing and explaining a graph, a better way to measure the rate than counting bubbles, and (Higher tier, spec point 6.6) the inverse square law: moving the lamp from 10 cm to 20 cm cuts the light intensity to a quarter.
When the rate stops rising, name the limiting factor that has taken over, such as carbon dioxide concentration or temperature. "It has reached its maximum" does not score.
Full method: light intensity and photosynthesis practical sheet. Notes: Photosynthesis and limiting factors. Combined Science: Combined version.
Core practical 8.11: The rate of respiration in living organisms
Aim: Use a simple respirometer to measure how temperature affects the oxygen uptake of small organisms.
Method in brief: Put soda lime in a tube, cotton wool above it and small organisms (such as germinating seeds) on top. Seal it with a capillary tube holding coloured liquid, stand it in a water bath and record how far the liquid moves in a set time at each temperature. The specification says safety and ethics must be covered.
Key variables: Independent: temperature of the water bath. Dependent: distance moved by the liquid in a set time, giving the rate in mm/min. Control: mass and type of organisms, amount of soda lime, the apparatus and the timing. A control tube with glass beads instead of organisms is set up alongside.
What exam questions ask: what the soda lime does, why the liquid moves towards the organisms, why the glass-bead tube is needed, a rate calculation, the volume of oxygen used with πr²h (a 0.5 mm radius and 30 mm movement gives about 23.6 mm³), and why the rate falls at 50 °C.
Saying the organisms "suck up" the liquid. The soda lime absorbs carbon dioxide, so as oxygen is used up the gas volume in the tube falls and the liquid is pushed towards the organisms.
Full method: rate of respiration practical sheet. Notes: Respiration. Combined Science: Combined version.
Core practical 9.5: Quadrats and belt transects
Aim: Investigate the relationship between organisms and their environment using field-work techniques, including quadrats and belt transects.
Method in brief: The specification describes a belt transect along a gradient, such as shade to open ground. Place quadrats at intervals along a tape, count one species in each and measure light intensity at each point. Random quadrats estimate a population over a whole area.
Key variables: Independent: position along the transect, which changes the light intensity. Dependent: the number of plants in each quadrat. Control: quadrat size, the species counted, the way plants are counted and the time of day for light readings.
What exam questions ask: why quadrats go down at random (to avoid bias), how to place them randomly, a population estimate from raw data (spec point 9.6), when to use a transect instead of random sampling, and why a correlation with light does not prove that light is the cause.
Work in three steps: mean per quadrat, then number per m², then multiply by the total area. A mean of 5 daisies in a 0.25 m² quadrat is 20 per m².
Full method: quadrats and belt transects practical sheet. Notes: Fieldwork and sampling. Combined Science: Combined version.
How to revise the Edexcel core practicals
- For each practical, write the aim in one line, then the independent variable, the dependent variable and two named control variables.
- Learn the calculation that goes with it: magnification, rate = 1 ÷ time, percentage change in mass, πr² for clear zones, πr²h for a respirometer, and population estimates from quadrats.
- Practise describing each method in numbered steps. Every one of our sheets ends with a 6-mark method question and a mark scheme.
- Learn to evaluate: spot an anomalous result, explain why repeats and means help, and give one specific improvement, such as collecting gas instead of counting bubbles.
- Mix in Edexcel GCSE Biology exam questions and flashcards, and tick each practical off on the specification checklist.
Questions often twist a practical you know, with a different organism or variable. Find what is changed and measured first, then apply the method you know.
If you would like help turning these methods into full-mark answers, we offer 1-to-1 tutoring online and in Dubai.