Microscope Diagram and Functions

Man's curiosity has led to great inventions. The microscope is one of them. Probably, it all started when man, by chance realized that a piece of crystal that is thicker in the center than in the edges could magnify images. Trials with different pieces of glass and crystal thus started, and slowly evolution of the microscope began. Although Anton van Leeuwenhoek of Holland is known as the father of microscopy, the credit for the earliest working form of microscope can be given to the Dutch father and son duo Zaccharias Janssen and his son Hans. Now the microscope has become an indispensable part of a biology laboratory. The microscope that is most commonly used is the compound microscope. Let us get to know about the diagram and functions in this article.

Types of Microscopes

Microscopes need illumination to work. Depending on the source of illumination, these instruments can be divided into two broad categories. They are:

• Light Microscopes: These microscopes use light rays to illuminate objects. Dissection microscopes and compound microscopes come in this category.
• Electron Microscope: These microscopes illuminate objects with the help of a beam of highly energetic electrons. Transmission electron microscope (TEM) and scanning electron microscope (SEM) are common types of electron microscopes. These microscopes provide better magnification than the light microscopes.

Microscope Diagram

The compound microscope uses light for illumination. Some simple compound microscopes make use of natural light whereas some have an illuminator attached to the base of the microscope that acts as the source of light. The specimen is placed on the stage and observed through different lenses of the microscope that have varying magnification powers. To have a better understanding of the function and basic structure of a compound microscope, let us follow the compound microscope diagram with labels that is given below:

Structural Microscope Parts

Parts	Functions
Body Tube	It is the part of the microscope that holds the eyepiece.
Arm	The arm connects the body tube to the base. It is this part that a user holds to move the microscope from one place to another.
Base	As the name suggests, the base is the lowest portion on which the whole structure of the microscope rests.

The following table describes functional microscope parts and their uses.

Functional Microscope Parts

Parts	Functions
Eyepiece	It is through the eyepiece that we look at the specimen placed on the stage of the microscope. It contains two or more lenses. The most common magnification for the eyepiece is 10X. However, they can also be 2x and 5x. An eye piece is a removable part that can be interchanged with another one of a different magnification.
Objective Lenses	There are more than one objective lenses. These are the primary lenses of a compound microscope and can have magnification of 4x, 5x, 10x, 20x, 40x, 50x and 100x. The magnification values are written on the side of each lens. The objective turret to which these lenses are attached, can be rotated with hand to get the lens of desired magnification to focus on the object.
Stage	It is the platform below the objective lens on which the object to be viewed is placed. There is a hole in the stage through which light beam passes and illuminates the specimen that is to be viewed.
Stage Clips	There are two stage clips one on each side of the stage. Once the slide containing the specimen is placed on the stage, the stage clips are used to hold the slide in place.
Diaphragm	It is located on the lower surface of the stage. It is used to control the amount of light that reaches the specimen through the hole in the stage.
Illuminator	Simple compound microscopes have a mirror that can be moved to adjust the amount of light that can be focused on the specimen. However, some advanced types of compound microscopes have their own light source.
The Adjustments	There are two adjustment knobs, the fine adjustment knob and the coarse adjustment knob that refine the focus of the lenses. The coarse adjustment knob helps in improving the focus of the low powers whereas the fine adjustment knob helps in adjusting the focus of the lenses with higher magnification.

The microscope is an important instrument in the world of biological sciences. Diagrams have always been of great help in understanding both the structural and functional aspects of entities in science. This microscope diagram and functions of the various parts that are labeled, gives the most basic understanding of a microscope. But just as we say 'practice makes a man perfect', here is a blank microscope diagram to label. Download the diagram and practice labeling the different parts of the instrument. All the best!