🔬 Intermediate Practical Manual – Compound Microscope

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🔬 Intermediate Practical Manual – Compound Microscope

The compound microscope is one of the most essential instruments in a biology laboratory. It allows us to observe minute details of biological specimens with great clarity and magnification.

🧪 Structure of Compound Microscope

  1. Base & Limb

    • The microscope has a strong basal foot (base) that supports a vertical limb.

  2. Stage

    • Fixed to the limb.

    • Can be round, rectangular, or square.

    • Provided with clips to hold the slide in place.

  3. Sub-stage

    • Located just below the stage.

    • Contains:

      • Iris diaphragm – regulates the amount of light passing through the specimen.

      • Condenser lens – focuses light onto the object.

  4. Mirror

    • A movable concave mirror at the bottom focuses light rays onto the specimen.

  5. Body Tube

    • Upper end → Eyepiece (different magnifications).

    • Lower end → Revolving nosepiece with three objectives:

      • Low power (10x)

      • High power (40x)

      • Oil immersion (100x)

  6. Adjustment Screws

    • Coarse adjustment – rapid movement of the tube.

    • Fine adjustment – slow and precise focusing.

⚙️ Mechanical Operation

a) Place the microscope in maximum diffuse light.
b) Adjust light with mirror, condenser, and iris diaphragm.
c) Place a prepared slide on the stage over the aperture.
d) Start focusing with low power objective using coarse adjustment.
e) For higher magnification:

  • Rotate the nosepiece to the next higher objective.

  • Use fine adjustment (avoid coarse adjustment at this stage).
    f) Use high power or oil immersion only if the specimen is properly mounted under a coverslip.

⚠️ Precautions

  1. Clean all lenses and metal parts before and after use.

    • Use tissue paper or muslin cloth for lenses.

  2. Handle operating screws, condenser, iris diaphragm, mirror, stage, and clips carefully.

✅ By following these steps and precautions, students can effectively use the compound microscope for practical experiments in biology.

👉🔬 Intermediate Practical Book 

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