LAUNCH · GCSE Biology · Week 3 · Explore
Calculating Magnification
🎯 Learning objective: I can calculate magnification, image size and actual size using consistent units.
✅ Success criteria
- Use magnification = image size ÷ actual size.
- Rearrange when the unknown changes.
- Convert mm and µm before calculating.
ArrivalStarterI DoWe DoI Do 2We Do 2IndependentExit
🧬 Edexcel GCSE Biology 1BI0 Foundation · Paper 1 · Topic 1🧪 Cell Scale Lab⏱ 40 minutes
🔬
Explore → Cell Scale Labobserve · predict · test · explain · applyQUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
Stable conditions and clear expectations make GCSE thinking possible.
⏱ 3 min
🚪 Arrival · previous learningRetrieve the previous learning: W3L1 magnification/resolution and lens combinations. Total magnification = eyepiece × objective.
Week 3 is the first taught week. R1 recalls last lesson. R2 and R3 have no earlier taught Biology to reach, so they ask what you already know. Declared, not hidden.
Not here last lesson? Everything you need is in the box above — read it, then answer.
◆ Supported — three retrieval questions and one lead-in
R1 Last lesson
Point to the eyepiece on the microscope diagram.
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Standard — Last lesson you separated magnification from resolution. Say what each one means.
R2 What you already know
Which is longer: 1 millimetre or 1 centimetre? Point to the longer one.
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Standard — How many millimetres are there in one centimetre?
R3 What you already know
Say or point: if something is 10 times bigger, is it larger or smaller?
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Standard — If a picture is 10 times bigger than the real object, how do you get back to the real size?
Lead-in Into today
Look at the drawing and the real cell. Point to the bigger one.
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Standard — A drawn cell is far bigger than the real one. How could we work out how much bigger?
▲ Standard — three retrieval questions and one lead-in
R1 Last lesson
Last lesson you separated magnification from resolution. Say what each one means.
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Stretch — Last lesson: a bigger image is not automatically more useful. Explain why.
R2 What you already know
How many millimetres are there in one centimetre?
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Stretch — Why does a calculation go wrong if two measurements are in different units?
R3 What you already know
If a picture is 10 times bigger than the real object, how do you get back to the real size?
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Stretch — Name the operation that undoes multiplying, and say when you would need it here.
Lead-in Into today
A drawn cell is far bigger than the real one. How could we work out how much bigger?
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Stretch — You have a drawing and the real size. Predict which calculation gives magnification.
★ Stretch — three retrieval questions and one lead-in
R1 Last lesson
Last lesson: a bigger image is not automatically more useful. Explain why.
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Supported — Point to the eyepiece on the microscope diagram.
R2 What you already know
Why does a calculation go wrong if two measurements are in different units?
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Supported — Which is longer: 1 millimetre or 1 centimetre? Point to the longer one.
R3 What you already know
Name the operation that undoes multiplying, and say when you would need it here.
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Supported — Say or point: if something is 10 times bigger, is it larger or smaller?
Lead-in Into today
You have a drawing and the real size. Predict which calculation gives magnification.
Non-reading route: point to it, say it, or show it. An adult can scribe your exact words. Next step up: Supported — Look at the drawing and the real cell. Point to the bigger one.
Arrival retrieves three times, then leads in. R1 is last lesson (W3L1); Week 3 is the first taught week, so R2 and R3 ask what you already know, and the lead-in opens today without teaching today’s concept.
LAUNCH response routes
📝 write / edit🗣 structured verbal📏 measure / calculate📊 graph / interpret🧪 practical / demonstrate🔁 re-attempt
Access changes the response route, not the GCSE Biology entitlement.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
Quiet retrieval before new demand; uncertainty is information, not public failure.
⏱ 4 min
🌱 Starter · observe / predict🔍 Scientific question
A cell image is 40 mm across but the real cell is 0.10 mm. How can one number describe how much bigger the image is?
FRAME 1/4
IDENTIFY THE QUANTITIES
Pause for observation or prediction before advancing.
FRAME 2/4
CHECK THE UNITS
Pause for observation or prediction before advancing.
FRAME 3/4
SUBSTITUTE CAREFULLY
Pause for observation or prediction before advancing.
FRAME 4/4
MAGNIFICATION HAS NO UNIT
Pause for observation or prediction before advancing.
🎯 Commit to a prediction
An image is 40 mm across. The real object is 0.5 mm. Before calculating: what will magnification be?
Choose one. Say it, point to it, or press it.
Nothing here is right or wrong yet, and nothing is marked, scored or stored. A prediction is still worth having when it turns out differently — that is what makes the test worth running.
LAUNCH response routes
📝 write / edit🗣 structured verbal📏 measure / calculate📊 graph / interpret🧪 practical / demonstrate🔁 re-attempt
Access changes the response route, not the GCSE Biology entitlement.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
Prediction/observation precedes explanation.
⏱ 4 min
👩🏫 I Do · model the reasoning🧠 Teacher reasoning model — reveal only after the class has observed/predicted.
STEP Identify the required quantity before substituting.
STEP Check units first; convert if necessary.
STEP Model 40 mm ÷ 0.10 mm = ×400; magnification has no unit.
✔ What this model helps us seeIt shows the three quantities together, so you can see which one you are solving for.
✘ What this model does not showIt leaves out that the units must match before you divide — the triangle looks the same whether your numbers are in millimetres or micrometres.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
Teacher models scientific reasoning; staff watch access and the point where the idea lands.
⏱ 4 min
🤝 We Do · hinge & responseCommit before reveal: Image 30 mm; actual 0.15 mm. Magnification?
Answer first. The reveal is earned by the response, not by a timer.
LAUNCH response routes
📝 write / edit🗣 structured verbal📏 measure / calculate📊 graph / interpret🧪 practical / demonstrate🔁 re-attempt
Access changes the response route, not the GCSE Biology entitlement.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
Adult genuinely receives the response; the next question, explanation or scaffold changes because of it.
⏱ 4 min
👩🏫 I Do 2 · connect / extend🧠 Teacher reasoning model — reveal only after the class has observed/predicted.
STEP actual size = image size ÷ magnification; image size = actual size × magnification.
STEP 1 mm = 1000 µm; convert before the equation.
STEP Use four-line working: equation → units → substitution → answer.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
Teacher models scientific reasoning; staff watch access and the point where the idea lands.
⏱ 5 min
🤝 We Do 2 · scientific model / dataInteractive reasoning: predict/observe first → use the model → explain the evidence → adult receives it.
📏 Local calculation lab
Use the lesson context to decide whether A/B are image size, actual size or another required pair. Units must be made consistent first.
📏 Unit bridge lab
The calculator above divides your two numbers. This lab is button-only. It shows the unit step that must happen first — and every number on it is worked out live by the same rule you use on paper.
Step 1 · Predict, before you test
1 mm is the same length as how many micrometres (µm)?
Choose one. Say it, point to it, or press it. Nothing here is right or wrong yet.
Step 2 · Test each working
Press one to test it.
Frozen results — these stay on the page
Nothing tested yet.
Step 3 · Explain
SCIENCE GLITCH: “50 mm ÷ 50 µm = ×1, because 50 ÷ 50 = 1.”
Use your frozen list as the evidence. Decide, then say why.
Every step is a button, and each option carries a shape and a word as well as its colour. Say it, point to it or have an adult press it — the route does not change the Biology.
LAUNCH response routes
📝 write / edit🗣 structured verbal📏 measure / calculate📊 graph / interpret🧪 practical / demonstrate🔁 re-attempt
Access changes the response route, not the GCSE Biology entitlement.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
Adult genuinely receives the response; the next question, explanation or scaffold changes because of it.
⏱ 12 min
✏️ Independent · evidence & transfer✏️ Independent GCSE Biology
Work through the mixed magnification problems. Some ask for actual size. Some ask for image size. Use the calculation lab. Then pick one answer. Explain your conversion. Or how you rearranged.
🧪 PRACTICAL / EVIDENCE READY
EquipmentCalculator; ruler; printed cell images; formula card; optional local table.
Safety / accessNo practical hazard. The equation remains visible as an access scaffold.
Evidence targetGCSE-style four-line workings + correct unit handling + one explained correction.
12 minutes. Supported / Standard / Stretch are movable routes, not grade identities.
◆ Do six calculations. Keep the equation visible. Keep the conversion ladder visible.
Keep the formula in view. Keep the mm↔µm ladder too.
Fade: remove the first prompt that no longer changes success.
▲ Do eight mixed calculations. Some need a conversion. Some need rearranging.
Find the unknown. Highlight it. Then rearrange.
Fade: remove the first prompt that no longer changes success.
★ Do the mixed calculations. Add a small lens/image data table.
Check it looks right. An enlarged image is bigger. Magnification is usually > ×1.
Fade: remove the first prompt that no longer changes success.
1 · Learner decisionprediction, plan, command-word choice or calculation set-up
2 · Observable Sciencemeasurement, graph, working, model, practical result or answer
3 · Learner responseexplanation, evaluation, edit or re-attempt after feedback
📖 WORD HELP
magnificationhow many times bigger the image is than the real thing
micrometreone thousandth of a millimetre
calculatework it out with numbers, showing the steps
Use the Biology word first. Ask for help only when you need it. TA fade route: model the word. Then prompt for it. Then wait for it. Drop a step as soon as the pupil no longer needs it.
LAUNCH response routes
📝 write / edit🗣 structured verbal📏 measure / calculate📊 graph / interpret🧪 practical / demonstrate🔁 re-attempt
Access changes the response route, not the GCSE Biology entitlement.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
Pupil reasoning stays attributable; feedback produces an edit, re-attempt, calculation, explanation or application.
⏱ 4 min
🎫 Exit · receive and use the response◆ Supported
Does magnification have a unit?
▲ Standard
Rearrange the equation for actual size.
★ Stretch
Explain why mixed mm/µm units must be converted first.
🔁 LAUNCH Lundy close — use the existing work
1) Pupil answers / edits / re-attempts. 2) Adult genuinely reads, listens or watches and names back what was received. 3) Where appropriate, the pupil adds the single response/next-step line on the same work: “I changed / next I will …”
No adult signature/countersignature. If local policy uses R, it follows genuine Audience only; this page never adds it automatically.
Closing the loop: this one ends on paper — your own hand, or your words scribed by an adult. Saying it aloud starts the loop; writing it is what closes it. Pass is always allowed.
What I said, and what it changed:
LAUNCH response routes
📝 write / edit🗣 structured verbal📏 measure / calculate📊 graph / interpret🧪 practical / demonstrate🔁 re-attempt
Access changes the response route, not the GCSE Biology entitlement.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: the explanation is earned by observation, prediction, measurement, testing or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
LAUNCH response stays on the existing work; adult genuinely receives it, then the next learning move changes.