To study the parts of a compound microscope.
A compound microscope is a high-resolution, multi-lens device used to view and magnify objects not visible to the human eye. It uses two sets of lenses providing a 2-dimensional image of the sample.
- Objective lens – The primary lens has a magnification capacity of 4X, 10X, 40X, or 100X, is positioned close to the object, and forms an inverted image with apparent magnification.
- Eyepiece or Ocular lens – The secondary lens or ocular lens is at the top to view the observed image.
Parts of a compound microscope
The parts of a compound microscope can be categorized into:
- Mechanical components - Including head, eyepiece tube, arm, stage, stage clips, nosepiece, condenser, focus knobs (coarse and fine adjustments), and base.
- Illumination Components - Including illuminator.
- Optical components - Including eyepiece (ocular lens), objective lens, diaphragm.
Head and eyepiece tube: The upper part of the head attached to the eyepiece tube supports optical components, maintains lens alignment, and supports the eyepiece tube for optimal performance.
Base and arm: The base and arm of the microscope provide stability and facilitate the connection of the base and upper parts, ensuring easy handling and transportation.
Stage and clips: The stage is a flat platform attached to the arm with an adjustable height. The clips help to hold the slides, and the center hole passes the light to the object.
Condenser: It is located under the stage and is positioned between the stage and the diaphragm. It regulates the light intensity that passes from the illuminator to the hole.
Nosepiece: It is a circular; rotating metal part positioned at the bottom of the body and holds three different objective lenses.
Focusing knobs (coarse and fine adjustments): The coarse adjustment knob adjusts for general focus by moving the body tube up whereas the fine adjustment is used for clear visualization.
Eyepiece (ocular lens): The eyepiece at the top of the body tube visualizes the magnified image by objective lenses to the closest view.
Objective lens: It is located at the top of the stage, magnifies and projects the magnified image of the specimen which can be observed through the eyepiece.
- Oil immersion objective (100X) - Ideal for maximum magnification to observe fine details, and enhance resolution, and clarity of the structure of bacteria or cellular components.
- High power objective (45X) - Ideal for detailed examination of specific specimen features after initial scanning.
- Low power objective (10X) – Ideal for initial observation and location, also offering a wide field view and frequent scanning of the entire specimen.
Diaphragm: The diaphragm, located below the stage controls the amount of light reaching the specimen. It is of two types: disc and iris.
Illuminator: It is the light source, either a mirror or light used to illuminate the object to the eyepiece.
Significance of compound microscope
- Magnification power allows to magnify the image clearly for a comprehensive analysis of the sample, yielding detailed information.
- User-friendly and easy to operate.
- Versatile application plays a major role in biology, medicine, and all material sciences for detailed study.
- Research assistance supports the study of new discoveries, providing enhanced visualization and strengthening research efforts.
Limitations of compound microscope
- Limited resolution: It has the limited capacity to display extremely fine details, particularly when using very high magnification.
- Sample preparation: Prior to examining under a compound microscope, many specimens require special preparation.
- Potential damage to specimens: Delicate specimens can be harmed if not handled carefully while being prepared for viewing under a compound microscope.
Uses of compound microscope
- Useful for learning about microorganisms and their functions, including cell division and cellular processes.
- Assists in analyzing studies of leaves, stems, roots, and reproductive organs to learn plant anatomy and physiology.
- Facilitates to understanding the structure of microorganisms using permanent slides and samples obtained from the environment.
- Eyepieces must be cleaned using a silk cloth and cleaning liquid before use.
- Avoid tilting while working or using the microscope.
- Start focusing the specimen from the lower magnification and then to the higher.
- Avoid objective lenses hitting the stage while focusing.
- For well–mount preparation, a coverslip must be used before observing.
- Ensure the immersion oil is applied before focusing on higher magnification.
- The concept of compound microscope.
- The various parts and working mechanism of the compound microscope.
- The significance, limitations, and uses of the compound microscope.