Aim:
To use a light microscope to observe, draw and label a selection of plant and animal cells
Equipment:
- Light microscope
- Microscope slides and coverslips
- Specimens: onion epidermis, cheek cells
- Stains: iodine solution, methylene blue
- Dropping pipette
- Filter paper or paper towel
- Mounted needle
- Ruler
Method:
- Set up microscope: Start with lowest magnification (×4 or ×10 objective)
- Prepare specimen: Place thin section on slide
- Add stain: Add 1-2 drops of appropriate stain
- Add coverslip: Lower at 45° angle to avoid air bubbles
- Place on stage: Secure with clips
- Focus on low power: Use coarse focus knob
- Center specimen: Move slide to find interesting area
- Switch to high power: Rotate to higher magnification
- Fine focus only: Use fine focus knob for sharp image
- Observe and record: Draw what you see with labels
⚠️ Safety Considerations:
- Handle slides and coverslips carefully - sharp edges
- Never force focus knobs
- Clean lenses with lens paper only
- Wash hands after handling stains
This required practical covers Required Practical: Using a Light Microscope within Microscopy for GCSE Biology. Light and electron microscopes, magnification and resolution calculations, specimen preparation, staining techniques, and practical microscopy skills It is section 8 of 20 in this topic. Revise both the method and the reason for each step, because practical questions often test understanding rather than pure recall.
Practice questions for Microscopy
What is magnification?
Explain why specimens are stained before viewing under a light microscope.
Quick recall flashcards
What is magnification?
Magnification is how many times larger an image appears compared to the actual object. It tells us how much bigger something looks through a microscope.
What is resolution?
Resolution is the ability to distinguish between two separate points that are close together. It determines how clear and detailed an image is.