Osmosis required practical lesson for AQA GCSE Biology 4.1.3.2: potato method, variables, percentage change, graph analysis, worksheets and answers.
What is this resource?
This is a complete lesson on the osmosis required practical for AQA GCSE Biology (8461), covering specification point 4.1.3.2 and Required practical activity 3: the effect of a range of concentrations of sugar or salt solutions on the mass of plant tissue. It is Lesson 11 of 11 in Topic 1: Cell biology and is designed to last 60 minutes.
Students plan and set up the potato cylinder investigation, practise calculating percentage gain and loss of mass while the cylinders are in solution, then weigh their own cylinders and analyse a graph. Realistic sample data is built in, so the calculations and graph work even if class results are unclear or you run the practical as a demonstration.
What’s included
• PowerPoint lesson (32 slides) with full teacher notes on every slide: timings, equipment list, safety, answers, mark schemes, misconceptions and questioning prompts.
• Starter on screen as students arrive, based on a real-world hook: salty soil affects about 10% of the world’s land and makes it hard for crops to take in water.
• Learning objectives at three levels of challenge: Developing, Secure and Mastery.
• Three learning activities: plan and set up the practical, calculate percentage change, and plot and analyse the graph. Each has a core task, a support option, a stretch task and a ‘stand back’ mini-whiteboard check with answers.
• Required practical essentials: aim, equipment, independent, dependent and control variables, hazards and safety, a step-by-step method with an apparatus diagram, a worked percentage change example, and evaluation of the method (anomalous results, repeats and means).
• Plenary exit ticket with one question per level, an answers slide for self-assessment and a return to the starter.
• Editable Word worksheets: a results table, a percentage change calculation sheet (core and support versions), a graph grid with data (core and support versions), and exam-style analyse and evaluate questions with a full mark scheme in the notes.
• Word lesson plan with objectives, lesson sequence, equipment, safety, differentiation, answers and common misconceptions.
Lesson outline
• Starter (5 min): Why do crops struggle to take in water from salty soil?
• Activity 1 (15 min): Identify the variables and hazards, then set up potato cylinders in six sugar solutions.
• Activity 2 (13 min): Calculate change in mass and percentage change using sample data, and explain why percentage change is used.
• Activity 3 (17 min): Reweigh the cylinders, plot a graph of percentage change against concentration, read where the curve crosses 0%, and evaluate the method.
• Plenary (8 min): Exit ticket at three levels, then self-assessment against the objectives.
Differentiation and inclusion
Every activity offers support and stretch that all students can choose, so no one is singled out. Support includes paired roles for the practical, calculator steps, a part-completed calculation table, and a graph grid with scales and the first points already plotted. Stretch tasks ask students to compare grams with percentages, write a full conclusion using data, and predict how sweet potato would differ.
The slides follow the British Dyslexia Association Style Guide: a clear sans serif font at a large size, a soft cream background, bold (not italics) for emphasis, left-aligned text and plain English. Graphs use crosses and labels rather than colour alone, levels of challenge never rely on colour, every slide has a proper title for screen readers, and every diagram has alt text.
How you could use it
• Teach it straight after a lesson on osmosis to complete the osmosis required practical.
• Run the practical as a class investigation or a demonstration, and use the sample data for the analysis.
• Use the percentage change sheet and graph questions for required practical revision before mocks and final exams.
• Use it as a cover lesson with the practical removed: the calculation, graph and question worksheets stand on their own.
Specification coverage
AQA GCSE Biology 8461, section 4.1.3.2 Osmosis, Required practical activity 3, including calculating percentage gain and loss of mass of plant tissue and plotting, drawing and interpreting graphs. Key words: osmosis, independent variable, dependent variable, control variable, initial mass, final mass, percentage change, curve of best fit, anomalous result, mean, repeatable. The previous lesson in the series is B1.10 Osmosis, and the next is B2.01 Levels of organisation and the digestive system.
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