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Guide to Effective Microscope Use

May 11, 2025

Lecture Notes: Using a Microscope

Introduction

  • Presenter: Dr. Rowe
  • Focus: Guide on using a microscope from scanning power to oil immersion system
  • Example used: Blood smear

Microscope Basics

  • Objective Lens: 4x
  • Ocular Lens (Eyepiece): 10x (can be 20x or 25x)
  • Total Magnification Calculation: Multiply objective by ocular lens (e.g., 4x objective and 10x ocular = 40x total magnification)

Initial Setup

  • Place the slide in the stage's "lobster claw."
  • Use knobs for slide movement:
    • Top knob: Moves slide forward and backward
    • Bottom knob: Moves slide side-to-side
  • Align the slide with the light source

Tips for Using the Microscope

  • Stage Position: Start with the stage at the highest position
    • Helps in locating specimens
    • Prevents slide breakage
  • Coarse Adjustment Knob: Used for large adjustments to focus

Focusing Strategy (Goldilocks Strategy)

  • Adjust focus until view is clear, then purposely defocus and refocus
  • Ensures precise focus, especially important for higher magnifications

Viewing and Centering

  • Find an area of interest and center it before increasing magnification
  • Field of view decreases with increased magnification (e.g., 40x to 100x)

Moving to Higher Magnifications

  • Low Power:

    • 10x objective lens
    • 100x total magnification
    • Focus carefully using the Goldilocks strategy

  • High Dry Power:

    • 40x objective lens
    • 400x total magnification
    • Adjust light intensity with rheostat knob

Observing Blood Cells

  • 99.9% red blood cells; white blood cells visible as purple structures
  • Center and focus areas of interest for better observation

Oil Immersion Technique

  • Oil Immersion Objective:
    • Necessary for highest magnification (1000x)
    • Use immersion oil (same refractive index as glass)
    • Transition smoothly from high dry to oil immersion for best focus

Final Steps

  • After use:
    • Lower the stage completely
    • Turn down rheostat knob
    • Turn off the microscope
  • Ensure proper cleanup

Conclusion

  • Comprehensive guide for microscope use in a lab setting
  • Encouragement to apply skills and knowledge gained

These notes provide a detailed overview of Dr. Rowe’s lecture on using a microscope efficiently, including practical tips and focusing strategies essential for laboratory settings.

Full transcript