Parts Of Compound Microscope - Practical No.1: Biology For Class IX (Science Group)

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EXPERIMENT No. 1 A:
TO STUDY THE DIFFERENT PARTS OF A COMPOUND MICROSCOPE. DESCRIBE EACH PART BRIEFLY. (Diagram not required in examination)

THEORY:
Compound microscope is an optical instrument which is used to see micro-organisms which cannot be seen by naked eye and works on the principle of magnifying glass.

REQUIREMENTS:
Compound microscope.

PROCEDURE:
Take a compound microscope and observe its different parts, draw its diagram and label it.

OBSERVATION AND DESCRIPTION OF PARTS OF MICROSCOPE:

1. BASE:
   Lower metallic horseshoe shaped foot of microscope is called base.
   FUNCTION:
   Base provides firm support and stability to the microscope.
   
   
2. ARM:
   It is a curved metallic rod which connects the body tube to the base.
   FUNCTION:
   Arm supports the body tube and is used to handle the microscope.
   
   
3. BODY TUBE:
   It is a metallic tube fitted with eye-piece lens at its upper end and revolving nose piece at its lower end on which objective lenses are screwed.
   FUNCTION:
   It is used to adjust the distance between object and objective which in turn focuses the object clearly.
   
   
4.  INCLINATION JOINT:
   It is an adjustable or movable joint between arm and base of microscope.
   FUNCTION:
   It is used for adjusting the angle of microscope to a suitable level.
   
   
5. STAGE:
   It is a metallic horizontal, square or rectangular area under the objective.
   FUNCTION:
   Slide is placed on the stage for viewing.
   
   
6. SUB-STAGE:
   It is a small piece below the stage which has two components.
   A. IRIS OR DIAPHRAGM:
   It is a folded circular screen having a hole in the center, which can be increased or decreased by a clip.
   FUNCTION: It is used to adjust the intensity of light.
   
   B. CONDENSER: It is a convex lens, placed between the holes of the stage.
   FUNCTION: It condenses the light.
   
   
7. STAGE CLIPS:
   Two shiny adjustable clips present on the stage one on either side of aperture.
   FUNCTION:
   Stage clips are used to hold the slide in place.
   
   
8. APERTURE:
   Hole in the center of stage is called aperture.
   FUNCTION:
   Aperture allows light coming from the mirror, for better viewing the specimen.
   
   
9. REFLECTOR:
   It is a movable circular frame having concave mirror on one side and plane mirror on the other side fitted in an adjustable circle bellow the stage.
   FUNCTION:
   It is used to reflect light in proper direction.
   
   
10. EYE-PIECE LENS OR OCULAR:
    The upper end of body tube holds a small tube fitted with a double convex lens called eye- piece. The eye- piece lenses are of different magnifying power.
    FUNCTION:
    In compound microscope eyepiece serves as a magnifying lens and forms magnified image.
    
    
11. NOSE PIECE:
    It is a rotating part of microscope at the bottom of the body tube.
    FUNCTION:
    It holds the objective lens.
    
    
12. OBJECTIVE LENSES:
    Nose piece holds small tubes fitted with double convex lens called objective.
    FUNCTION:
    Objective forms a real, inverted and magnified image of object.
    
    
13. COARSE ADJUSTMENT KNOB:
    It is a large, round knob on the side of microscope.
    FUNCTION:
    It is used for focusing the specimen, it may move either the stage or the upper part of microscope.
    
    
14. FINE ADJUSTMENT KNOB
    It is small round knob on the side of microscope.
    FUNCTION:
    It is used to fine-tune the focus of specimen after using the coarse adjustment knob.

PRECAUTIONS:

• Handle microscope carefully.
• Adjust the reflecting mirror to get an illuminated screen.
• First focus the object under low power by using coarse adjustment screw (knob).
• After focusing under low power, focus the object under high power by using fine adjustment screw (knob).

DIAGRAM

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