Microscope Object Lenses Tube

Microscope Object Lenses Tube 

Exercise No-1

Acquaintance with a microscope and other laboratories (types of equipment.)

Parts of the Student’s Microscope
Thebe ape telo objectives in student’s microscope:
Instruction for use of a microscope –
Methods of sterilization and disinfection –

1) physical agents –2) chemical agents – Principle —

Precautions to be taken while working with autoclave

To get mastery of the use of the microscope which is the basis to go through the understanding of I microbiology

The lenses in this instrument all so adjusted that a minute object invisible to naked eyes is magnified and made visible. There are two types of microscopes is common I use,

1)   Simple microscope – Only one lens Cor one set

  of lenses) is used in between the eye and teat- Hand lenses f dissecting                          microscope

2)   Compound Microscope – Two or more than two lenses Corset of lenses) are used in between the eye object and this helps in obtaining more magnification. eg.  Student’s microscope, Research microscope.

1)   Eyepiece (ocular) A single set of lenses placed on the – Upper End of a body tube with usual magnify cation of 5x, 10x, 152, etc. The function of eyepiece I is to O magnify the object to a certain extent.

2)   Body tube Coraw tube) »The tube holding the eyepiece and the objective | lenses at upper and lower end respectively.

It is fitted to the arm by back and pinion I arrangement for upward and downward movement.

the length of the tube is fixed f is generally F160mm.

3)   Objective lenses

One or more sets of lenses are fitted to the lower end of the body tube. with the help of devolving nosepiece

1)   Lopower objective = it is having a magnification of 10x ‘or 20x

2)   High power objectives – It is having a magnification of 44x or 62

4)   It is a curved, solid, steel frame holding the Draco tube at the upper and stage at the lower end. It is fitted to the pillar by an inclination joint.

5)   Stage and clips:
The stage is useful for placing the object slide, whereas clips are used for holding the object slide.

6)   Inclination joint –

Pt is used for changing the inclination of the microscope to a certain extent for easy observation.

7)   Course or rough adjustment Screw:

It is meant for bringing the microscopic objects after focusing! by course adjustment of the microscopic object under focus.

8)   fine adjustment Screw –

It is love sharp focusing of the microscopic

object after focusing by course adjustment Screw

9)   Pillar & horseshoe-shaped base :

It is the basal part bolding the arm & other parts in balance?

10)  Mirror

A mirror with two surfaces (concave & plain)  is fitted to the pillar for reflecting light  to the object

11)       Diaphragm —

It’ is ametal disc with adjustable Centocel holes For controlling the quantity of light.

1)   It is a costly and delicate instrument. Handle it with maximum care.

2)   clean all Optical parts, mirror, and condenser I before use. use a separate cloth to clean the body of the microscope.

3)   Use the microscope in Vertical position, keep it to face the light source but avoid direct’ Sunray’s.

4)   focus light under, low power objective with mirror,

5)   Do not mount bot or flooded slide under the microscope

6)   Select Suitable microscopic Jield under low Land there observe it under high power or immersion objectives

7)   Never lower down the objective while viewing through eyepiece protect & slide from breakage, first lower down the objective just to touch the condo slip & lift it | upwards to focus while viewing through the eyepiece.

8)   clean the oil’ immersion objectives ofter use with xylol &wipeout with the muslin cloth.

9)   Turm to low power objectives while replacing the

      Slide or closing the work.

Object – To keep the material Free from micro-organisms

Sterilization it is a process by means of which material is made sterile or free from living micro – organisms either by killing or by separating them.

It is essential to sterilize cultural media glassware and other laboratory instruments before their

use to avoid contamination. In pure culture Studies, different physical & chemical means are used for this a purpose which will follow

 i) Heats –

 a) Dray : 1) Direct; Eg. flame 2) Indirect ‘ l.e Hot air over

 b) Moist :1) Steam without pressure – Arnold steam sterilizer. 2) Steam with pressure – autoclave.

 ii) Filters – 

a)   for liquids – porcelain on glass filters like(a) chamber land (b) Berkefeld  (c)    site

b)   for gases – cotton fibers, etc.
iii) light. – Ultraviolet rays : (2) Germicidal lamps.

1)     Inorganic KM No 4, Iodine

2)      Organic – phenol, formaldehyde, ethyl alcohol etc.

The material is exposed to ordinary steams i.e. 100-110 °C for 20-30′ minutes and the process is repeated for successive 2 more days with an interval of 24 hrs. 

These repeated treatments kill the Resistant Spare farmers that germinate during the info retted’ period, The process is also known as fractional or process is also known as fractional or intermitted’ Sterilization or Tantalization.

The apparatus. Arnold Steam Sterilizer consists of a double-walled copper chamber with water-holding trays at the bottom. 

The material to be sterilized’ is placed on perforated sieves Steam rising from the bottom. beats. The material gets Condensed at the top and returns to be boiling trays through space in between two walls. 


can be done’ by either electric beaters or gas burners.

Moist heating the steam under pressure (Autoclave)

Culture media like potato Dextrose Adale (P.D.A), nutrient broth (NB), Nutrient agar (N. A). and soil, water, and manure, etc, which are not damaged by the high temperature of the steam under

pressure has a high temperature and more power that is penetrating and bence. It is the quickest method Materials usually sterilized by direct beating or bot air can also be sterilized by this method. 

The apparatus used in this method is called an autoclave.

1)    Equipment must be in cooking Order,

2)   Sufficient water should be filled before beating a

3)    pressure is allowed to rise only when all air from in the side is removed through aircock

4)   Alben desired pressure is obtained. It is maintained for a specific time.

5)   After sterilization, the apparatus is allowed to cool doco on and the pressure is slowly released before opening

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