Example 1 of 4 Year 6 Science · Osmosis · UK LESSON PLAN Subject: Science Grade / Year: Year 6 (ages 10–11) Learning Objective: Students will understand how plants absorb water through the process of osmosis Total Duration: 60 minutes Teaching Style: Enquiry-based Class Size: 28 students (mixed ability) ──────────────────────────────── HOOK ACTIVITY (8 minutes) ──────────────────────────────── Teacher instruction: Place two identical celery stalks on the front desk — one that has been sitting in coloured water overnight (visibly changed) and one left in plain water. Ask the class: "What do you notice? What do you think happened? How did the colour get all the way up there?" What students do: Students observe both stalks, discuss with a partner for 2 minutes, then share ideas with the class. Record key student theories on the whiteboard without correcting them yet. Materials needed: Two celery stalks prepared the previous day, one in red food colouring water, one in plain water. Whiteboard and markers. ──────────────────────────────── MAIN TEACHING INPUT (18 minutes) ──────────────────────────────── Step 1: Revisit prior knowledge Ask: "Who can remind me — what is a cell membrane?" Take two or three responses. Establish that membranes are selectively permeable — they let some things through and not others. Draw a simple diagram on the board. Step 2: Introduce osmosis Define osmosis clearly: "Osmosis is the movement of water molecules from an area where there is a lot of water to an area where there is less water, through a membrane that water can pass through." Write the definition on the board and ask students to copy it into their books. Step 3: Explain the mechanism Draw two sides of a membrane on the board — one side with many water molecules (high concentration), one side with fewer (low concentration). Use arrows to show water moving from high to low concentration. Ask: "Which direction is the water moving? Why?" Step 4: Connect to the celery Return to the celery hook. Ask: "So using what we just learned — why did the colour travel up the celery stalk?" Guide students to the answer: water moved by osmosis from the glass into the celery cells, carrying the colour with it. Key questions to ask throughout: - Why does water move in one direction and not the other? - What would happen if both sides had the same concentration? - Can you think of another example in nature where this might happen? ──────────────────────────────── STUDENT ACTIVITY (22 minutes) ──────────────────────────────── Task: Osmosis investigation and diagram Part 1 — Individual (12 minutes): Students draw and label a diagram showing osmosis across a cell membrane. They must show water molecules, the membrane, concentration on each side, and the direction of movement. A word bank is provided on the board: osmosis, membrane, concentration, selectively permeable, water molecules, high, low. Part 2 — Paired discussion (5 minutes): Students discuss with their partner: "What do you think would happen to a plant cell if you watered it with very salty water instead of plain water?" Students write a prediction in one sentence. Part 3 — Class share (5 minutes): Take three or four pairs to share their predictions. Guide the class toward understanding that high salt concentration outside the cell would draw water out — the reverse of normal osmosis. Grouping: individual then paired Expected output: completed diagram and one written prediction sentence ──────────────────────────────── ASSESSMENT MOMENT (7 minutes) ──────────────────────────────── Exit ticket: Each student answers three questions on a slip of paper before leaving: 1. In your own words, what is osmosis? (one sentence) 2. Draw an arrow on this diagram to show which way water will move. (pre-drawn diagram on slip) 3. Give one real-life example of osmosis in plants. Teacher use of information: Review slips before the next lesson. Students who cannot answer question 1 correctly need a brief recap at the start of the following lesson. Students who answer all three correctly are ready to move to the next topic — how osmosis is affected by solute concentration. Materials: pre-printed exit ticket slips or students write on a piece of paper torn from their books. ──────────────────────────────── DIFFERENTIATION NOTES ──────────────────────────────── Higher ability students: Challenge extension task — ask these students to research and write two sentences explaining what happens to animal cells (red blood cells) when placed in water with very high or very low salt concentration. Introduce the terms turgid, plasmolysed, and crenated and ask them to match each term to a diagram. Lower ability and additional needs students: Provide a pre-drawn, partially labelled diagram for the main activity so students are completing and annotating rather than drawing from scratch. Pair with a confident peer during the paired discussion section. Reduce the exit ticket to question 1 and question 2 only. Use physical manipulatives — small counters representing water molecules — during the main teaching input to make the concept concrete. ──────────────────────────────── RESOURCES NEEDED ──────────────────────────────── - Two celery stalks (prepared previous day, one in red food colouring water) - Whiteboard and markers - Student exercise books or blank paper - Word bank written on board before lesson - Pre-printed exit ticket slips (or students use scrap paper) - Optional: counters or small objects for lower ability manipulative support - Optional: printed osmosis diagram for lower ability scaffolding