Science lesson plan · 7th grade (Year 8 in England) · 45 minutes
Plasma, red cells, white cells and platelets
Human body and health
CCSS NGSS.MS-LS1-3England: GCSE Combined Science: Organisation
Objective and success criteria
Students will: Plasma, red cells, white cells and platelets.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Arteries, veins and capillaries compared
Leads to: the next skill in this area.
Materials: Stopwatches, Body diagrams, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 5 min
- 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.
- Which type of blood vessel: carries blood away from the heart at high pressure? (artery / vein / capillary) → arteryPrompt: Think about pressure: high, low, or for exchange?
- Blood vessels: which statement is true? (Arteries carry blood away from the heart. / Veins have thicker walls than arteries. / All arteries carry oxygen-rich blood. / Capillaries have thick walls to protect the blood.) → Arteries carry blood away from the heart.Prompt: Do all arteries carry oxygenated blood? Check the one going to the lungs.
- Why are capillaries so narrow and thin-walled? (to raise blood pressure / to bring blood very close to cells for quick diffusion / to stop blood reaching cells / to store blood) → to bring blood very close to cells for quick diffusionPrompt: Diffusion is fastest over short distances.
Hook · 5 min
- 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.
I do: model it · 10 min
- 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.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Which part of the blood is described here: help blood to clot at a cut? (red blood cells / white blood cells / platelets / plasma) → plateletsPrompt: Blood has three kinds of cell or fragment floating in a liquid.
- Climbers living high in the mountains often have more red blood cells. Why is this useful? (Mountains contain more iron / It helps blood clot in the cold / They need more antibodies / There is less oxygen in each breath, so more cells help carry enough) → There is less oxygen in each breath, so more cells help carry enoughPrompt: What do red cells carry?
You do: independent practice · 10 min
- 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 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Blood: which statement is true? (Blood is a single kind of cell. / Platelets carry oxygen. / White blood cells are the most common blood cells. / Platelets help form a clot that seals a wound.) → Platelets help form a clot that seals a wound.Prompt: Which part of the blood carries oxygen?
- Which part of the blood is described here: engulf microbes? (red blood cells / white blood cells / platelets / plasma) → white blood cellsPrompt: Blood has three kinds of cell or fragment floating in a liquid.
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Arteries, veins and capillaries compared.
- Use concrete materials: stopwatches.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-7.
Free lesson plan from eurekami.com/lesson-plan-builder