Lesson plan
Biology · Unit 3.2 Cells and transport · Kastanjehof College, Deventer
By the end of the lesson, learners can …
| Time | Phase | Teacher & learner activity | Materials |
|---|---|---|---|
| 0–8 min | Starter | Pairs recall Thursday's raisin demo (tap water versus syrup) and write one sentence on the mini whiteboard explaining the difference in mass. Two are read out and sharpened against the word concentrated. |
Mini whiteboards, markers |
| 8–18 min | Input | Build the partially permeable membrane diagram on the board step by step while learners annotate the printed copy: arrows for water, crosses for solute. Cold-call three learners for the direction of net movement. |
Diagram handout ×30 |
| 18–25 min | Modelling | Work one calculation on the visualiser: 2,00 g → 2,24 g, so % change = 0,24 / 2,00 × 100 = 12,0 %. Learners copy it, then do the 1,86 g → 1,71 g case alone and check with a neighbour. |
Visualiser, results grid |
| 25–45 min | Practical | In sixes: bore six cylinders, trim to 30 mm, blot, weigh to 0,01 g, one cylinder into each solution (0 – 1,0 M), timer set to 15 minutes. While they soak, every group sketches its predicted graph on the results grid. |
Full bench set — see checklist |
| 45–55 min | Review | Blot, re-weigh, record. Each group calculates its % change and plots one point on the class graph. Circle the outliers and ask what a cylinder that was left wet does to the reading. |
Class graph on board, calculators |
| 55–60 min | Plenary | Exit ticket: “a gardener over-feeds the soil and the seedlings wilt — explain in two sentences, using the word osmosis.” Collected at the door in one unnamed pile. |
Exit tickets ×30 |
During the soak, circulate and ask every learner which way the water is moving and why; start at bench 4, who stayed quiet through diffusion.
The class graph is the live check on method — a group whose 1,0 M point sits above zero has not blotted, so correct it before the line is drawn. The exit tickets are the record: full marks need the direction of movement and the words “more concentrated”. If more than six miss it, re-teach from the raisin photographs on Thursday.
Support — bench 3 receives the results grid with row 1 completed and the formula printed above it; cylinders pre-cut so weighing starts on time.
Stretch — bench 1 also gets 1,5 M and predicts where the line crosses the x-axis (the isotonic point) before plotting.
Workbook p. 44, questions 1–4 (osmosis in root hair cells) — due Thursday 10 Sep. Anyone absent today uses the class data set on the shared drive.