Science lesson plan · 7th grade (Year 8 in England) · 45 minutes
Microscopes and magnification
Cells, genetics and evolution
CCSS NGSS.MS-LS1-1England: KS3 Biology: Cells and organisationEngland: KS4 Combined Science: Cell biology
Objective and success criteria
Students will: Microscopes and magnification.
- 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: Plant and animal cells
Leads to: Measure tiny things in mm, µm and nm
Materials: Microscope images or slides, Cell 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 (Plant and animal cells). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which part of a cell strengthens and supports a plant cell? (cell wall / mitochondria / nucleus / chloroplasts) → cell wallPrompt: Think about which parts are only in plant cells.
- Cells: which statement is NOT true? (Bacterial cells have no nucleus. / Both plant and animal cells have a nucleus, cytoplasm and a cell membrane. / Plant cells have a cell wall but animal cells do not. / All plant cells have chloroplasts.) → All plant cells have chloroplasts.Prompt: Do plant cells respire?
- Which part of a cell contains the genetic material? (nucleus / mitochondria / chloroplasts / cell wall) → nucleusPrompt: Think about which parts are only in plant cells.
Hook · 5 min
- Show a microscope image of cells and ask what students think they are looking at.
- Share the objective: Microscopes and magnification. 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: A microscope has a ×10 eyepiece lens and a ×10 objective lens. What is the total magnification?
- Step 1: 10 × 10 = 100
- Step 2: So the answer is: ×100
- Answer: 100
- 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.
- A microscope has a ×5 eyepiece lens and a ×4 objective lens. What is the total magnification? → 20Prompt: Combine the two lenses.
- A cell is 0.02 mm wide. It is viewed at ×40. How wide is the image, in mm? → 0.8 mmPrompt: magnification = image size ÷ actual size
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.
- A cell is 0.1 mm wide. It is viewed at ×400. How wide is the image, in mm? → 40 mmPrompt: magnification = image size ÷ actual size
- A microscope has a ×10 eyepiece lens and a ×40 objective lens. What is the total magnification? → 400Prompt: Combine the two lenses.
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: Plant and animal cells.
- Use concrete materials: microscope images or slides.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Measure tiny things in mm, µm and nm.
- 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