What are the parts of a Compound Microscope?


The compound microscope is mainly used in chemistry, biology or microbiology labs for detecting and identifying microorganisms. The particles that cannot be seen through the naked eyes are placed under the microscope in order to get an enlarged image of the tiny particles. A higher rate of magnification can be achieved easily by combining the two lenses of the compound microscope.

What is a Compound Microscope?

The compound microscope is determined as the modernized microscope which has a higher rate of resolution. Two effective sets of lenses are used in this type of compound microscope as they provide a two-dimensional image for the given sample under the microscope. At the higher magnification rate of about 40 to 1000x the samples of tiny microorganisms can be viewed and identified properly. The two major lenses that are used in the microscope include the objective lenses that remain close to the given samples and the ocular lens referred to as the eyepiece.

The compound microscope is also determined as the optical microscope. The lenses that are used in this type of microscope help to magnify the objects that are placed under it. The ocular lens is used for bringing the substance closer to the eyes of the observer.

Aim of the Experiment

The main aim of the experiment is to study all the parts of the compound microscope and their uses and functions. The study also helps to understand the working principle of the compound microscope which is used in the science laboratory to detect the structure of the microorganism.

Parts of the Compound Microscope

The two major parts of the compound microscope that are commonly used in the modernized science laboratory are mentioned below.

Figure 1: Parts of a typical compound microscope

Optical Parts

  • Foot [base]: The foot has a U-shaped structure and is determined as the major part on which the compound microscope stands.

  • Pillar: The pillar is the stand that is present on the stage and provides a perpendicular projection.

  • Stage: The stage of the microscope is the rectangular structure having a hole at the centre through which the light travels. It is placed below the eyepiece and the samples are placed at this stage.

  • Arm: The arm is the curved-shaped structure that manages the entire microscope and its work.

  • Clips: The clips are present on the slide side of the stage which helps to hold the samples.

  • Diaphragm: The structure that is situated below the stage which controls the light intensity is denoted as the diaphragm.

  • Nose piece: The tube consisting three holes in order to fit the objective lenses

Other major parts of the compound microscope also include fine adjustment coarse adjustment knobs and body tubes.

Mechanical parts

  • Mirror: Two types of mirrors are used including concave and plain mirrors which are placed below the stage. Mirrors help the light to focus on the objects placed under the lenses.

  • Objective Lenses: The lens is of various types including Oil immersion objective (100X), High power objective (45X), and Low power objective (10X). The lens is placed at the bottom of the body tube and connected to a revolving nose piece.

  • Ocular Lens: On the eyepiece rim, the markings of the Ocular lens are denoted as 5X, 10X, 15X, and so on. The lens has the power of magnification.

Working Principles of a Compound Microscope

A compound microscope works through various parts as mentioned below.

  • After rearranging the mirror through which the light will pass into the microscope, one can view the sample through the eyepiece.

  • The slides, lenses, stages, and mirrors must be kept free from dust and clean.

  • The slide of the sample is kept inside the stage of the microscope. It also needs to be kept secured with a cover slip or clips from two edges.

  • The adjustment of the nose pieces is made in such a manner the lower objective power remains aligned with the focus plane of the slide.

  • The adjustment of the knob is kept flexible so that the microscope can move up and down during observation.

  • The rate of magnification is kept high so that the detailed structure of the objects can be observed well.

Uses and Functions of a Compound Microscope

Figure 2: Chlorophyll under microscope

Various functions are there for the compound microscope used in the laboratory as mentioned below.

  • The compound microscope is small and is comfortable to use and easy to operate. In a simple microscope, the researchers often face a common problem as the resolution is limited.

  • In the case of a compound microscope, the resolution can be set on the basis of the requirement. The compound microscope also has magnifying properties greater if compared to a simple or traditional microscope.

  • The samples of particles that cannot be seen by naked eyes can be placed under a compound microscope in order to get a magnified view.


The word compound microscope denotes the utilization of two or more lenses in the microscopic set up. The advantages include the achievement of a higher rate of magnification, as the microscope is set up with two effective lenses instead of one lens. The compound microscope comes with its own source of light which reflects on the objects and helps the observers to continue their research properly.


Q1. What are the main functions of a compound microscope?

Ans. The major function of a compound microscope highlights that they are often used in microbiology or biology laboratories in order to view and detect microorganisms. Enlarged images are formed through the lenses of the compound microscope.

Q2. What are the parts of the compound microscope?

Ans. The compound microscope has two major parts that are commonly used in the modernized science laboratory. The parts include optical parts and mechanical parts.

Q3. What are three types of objective lenses used in a compound microscope?

Ans. Objective lenses are connected to a revolving nose piece. The major types of objective lenses include Oil immersion objective (100X), High power objective (45X), and Low power objective (10X).

Updated on: 24-Apr-2023


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