Microscope

Introduction to Microscope Practicals

Microscope practicals aim to develop skills in properly operating a microscope and directly observing microscopic cell structures (such as plant and animal cells) in a laboratory setting.

 

Tools and Materials

 

• Tools: Light microscope, glass slide, cover slip, pipette, scalpel/tweezers, absorbent paper/tissue.

• Materials: leafs, red onion (for plant cells), prepared animal cell slide, distilled water, staining solution (e.g., methylene blue or iodine).

Step-by-Step Practical Procedure

 

• Preparing a Fresh Mount (Onion Cell or leaf cell):

  • Carefully peel a thin, transparent layer from the inner scale of an onion or leaf surface using a scalpel or tweezers.

  • Place the thin membrane flat onto the glass slide (ensure it does not fold).

  • Add 1 drop of distilled water or methylene blue stain over the specimen to enhance cellular visibility.

  • Gently lower the cover slip over the sample at a 450 angle to prevent air bubbles from trapping inside.

• Observation Under the Microscope:

   

  • Place the microscope in an area with adequate lighting.

  • Set the objective lens to the lowest magnification first (e.g., 4x or 10x).

  • Adjust the mirror/light source and diaphragm until the field of view is brightly illuminated.

  • Place the slide on the stage and secure it with the stage clips.

  • Turn the coarse focus knob to move the stage/tube until the object comes into view.

  • Turn the fine focus knob slowly to sharpen the image until the cells are clearly focused.

  • For higher detail, rotate the nosepiece to a higher objective lens magnification (e.g., 40x).

     

    Observation Results 

   

   

   

   

  Report Format

   

   

   

   

  Important Notes & Safety Guidelines

   

• Avoid Air Bubbles: Trapped air bubbles appear as thick black rings and obstruct the view of the specimen.

• Carrying the Microscope: Always carry the microscope with one hand holding the arm and the other hand supporting the base.