• Quick retrieval from earlier learning (Arteries, veins and capillaries compared). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Which type of blood vessel: where substances are exchanged with tissues? (artery / vein / capillary) → capillaryPrompt: Think about pressure: high, low, or for exchange?
2. Blood vessels: which statement is true? (Capillaries have thick walls to protect the blood. / All arteries carry oxygen-rich blood. / Veins have thicker walls than arteries. / Capillaries link arteries to veins.) → Capillaries link arteries to veins.Prompt: Do all arteries carry oxygenated blood? Check the one going to the lungs.
3. A blood donor has a needle put into a vein, not an artery. Why? (Arteries have no blood in them / Veins are near the surface and the blood is at low pressure / Veins carry oxygen-rich blood / Veins have thicker walls) → Veins are near the surface and the blood is at low pressurePrompt: Think about pressure and bleeding.

• Ask everyone to find their pulse, then jump for 30 seconds and find it again.
• Share the objective: Plasma, red cells, white cells and platelets. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Which part of the blood is described here: help blood to clot at a cut?
• Step 1: Platelets are cell fragments that help blood clot.
• Step 2: So the answer is: platelets
• Answer: platelets
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. Which part of the blood is described here: carry oxygen? (red blood cells / white blood cells / platelets / plasma) → red blood cellsPrompt: Blood has three kinds of cell or fragment floating in a liquid.
2. After a big meal, which part of the blood carries most of the absorbed glucose? (plasma / platelets / red blood cells / white blood cells) → plasmaPrompt: Glucose is dissolved in the liquid part of the blood.

• Students work on the student sheet. Circulate and check the first two answers of every student early.
• Students who finish: write a question of their own for a partner, with the answer.

The 6 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. Climbers living high in the mountains often have more red blood cells. Why is this useful? (There is less oxygen in each breath, so more cells help carry enough / Mountains contain more iron / They need more antibodies / It helps blood clot in the cold) → There is less oxygen in each breath, so more cells help carry enoughPrompt: What do red cells carry?
2. Blood: which statement is true? (Blood is a single kind of cell. / White blood cells are the most common blood cells. / Platelets carry oxygen. / White blood cells help fight infection.) → White blood cells help fight infection.Prompt: Which part of the blood carries oxygen?

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-7.