INTERACTIVE PRACTICAL · BIOLOGY LAB 01

Microscope Skills Lab

Explore a compound light microscope, practise focusing, compare specimen views at different magnifications and record evidence like a laboratory investigator.

Interactive microscopeMagnification calculatorObservation notebookPractical assessment

MICROSCOPE CONTROL DECK

SETUP

SPECIMEN & OPTICS

Specimen Eyepiece lens Objective lens Coarse focus 50% Fine focus 50% Illumination 70%

100×Total magnification

1.80 mmApprox. field diameter

Formula
Total magnification = eyepiece magnification × objective magnification.
Field diameter is a simplified model estimate: 18 mm ÷ objective power.

Start with the 4× objective, centre the specimen, then refine using fine focus.

LEARNING OUTCOMES

SUCCESS CRITERIA

Identify the main microscope parts and their functions.
Calculate total magnification correctly.
Explain why low power is used first.
Describe how focus and illumination affect image clarity.
Record observations using scientific language.

EXPERIMENT WORKBENCH

LIVE MODEL · SPECIMEN VIEW

Onion epidermal cells · simulated viewIMAGE NOT YET FOCUSED

10× objective · 100× total

Simulation only · not a calibrated optical instrumentFocus quality: adjusting

How to use the microscope
1. Select a specimen and begin with the scanning objective. 2. Use coarse focus to bring the image close to focus. 3. Switch to fine focus for sharp detail. 4. Increase objective power only after locating the specimen. Adjust illumination to improve contrast.

—Image clarity

—Relative structures in view

Scientific analysis

Use the model to compare how objective power, focus and illumination change what can be observed. Record each controlled trial before drawing a conclusion.

100×Calculated magnification

1.80 mmEstimated field diameter

Interpretation prompt
As objective magnification increases, the specimen appears larger, but the field of view becomes smaller and less of the specimen can be seen at once. Higher magnification also requires more careful focusing and suitable illumination.

Research hypothesis Evidence-based conclusion

Investigation design
Independent variable: objective magnification.
Dependent observations: apparent size, field diameter and image clarity.
Controlled variables: specimen, eyepiece, illumination and focusing procedure.

Observation notebook

Record a trial after adjusting the microscope. Include what changed and what you observed.

Trial	Specimen	Objective	Total mag.	Field (mm)	Clarity
No trials recorded yet.

Observation notes What could affect reliability?

Practical skills assessment

Complete the matching activity and knowledge questions. Feedback is immediate.

Challenge A · Match microscope skills
Select an item, then select its matching function.

Match all three items correctly.

Challenge B · Knowledge check

Answer all questions to complete the check.

0/5Correct answers

0%Practical progress

Teacher assessment rubric
Microscope setup and safe handling (2); focusing sequence (2); magnification calculation (2); scientific observations (2); evidence-based conclusion (2). Total: 10 marks.

LIVE ANALYSIS

MODEL OUTPUT

100×Total magnification

—Focus state

PRACTICAL COMPLETION

Complete model run, record trials and assessment.

PROCEDURE & SAFETY

GOOD PRACTICE

Carry the microscope with two hands.
Place it on a stable, level bench.
Begin with the lowest-power objective.
Use coarse focus only on low power.
Use fine focus at high power.
Do not allow the objective lens to touch the slide.

Safety note
This is a digital model. In a real laboratory, handle glass slides carefully, follow teacher instructions and never force the focus controls.

CONCEPT COMPANION

KEY IDEAS

TOTAL MAGNIFICATION

Eyepiece × Objective

Example: 10× eyepiece × 40× objective = 400× total magnification.

FIELD OF VIEW

The visible circular area generally becomes smaller as objective magnification increases.

FOCUSING

Coarse adjustment makes large focus changes; fine adjustment makes small, precise changes.

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