Indeed the invention of microscopes has been a milestone in the field of scientific studies and research. Today, microscopes of different magnifying powers are used in several applications.
To mention a few, a simple microscope with only one magnifying lens is used in schools, while a compound microscope with more than one lens is used in high schools, colleges, and advanced scientific studies. Likewise, scientists and forensic researchers make use of an electron microscope, which has a very high resolution power.
Majority of us are well acquainted with a compound microscope. Remember your school days, when your teacher demonstrated the use of this device for the first time. Each of the parts in the microscope is responsible for a specific function, which collectively result in a magnified view of the object under observation.
Parts of a Microscope and their Functions
The compound microscope uses light rays and multiple lenses for creating a magnified view of the specimen or object. As visible light plays a crucial role in the overall working of this device, it is also referred to as a light or optical microscope.
The magnifying power of this device ranges between 1,000 to 2,000 times, depending upon the types of lenses that are used while viewing. This value is quite higher than that of the traditional simple microscope, which enlarges an object to about 100 - 300 times.
Broadly speaking, there are three components of a compound microscope - head (body), arm, and base. The head refers to the upper portion of the device and houses the optical lenses, whereas the base comprises the illuminator and supports the microscope.
The bottom portion of the microscope is connected to the head via the arm, and is basically used for handling of the device. Following is a list of the different parts of a microscope, arranged according to their position from top to bottom.
Labeled Diagram of the Body Parts of a Microscope
Also known as ocular, the eyepiece is the lens, by which the specimen is viewed in a compound microscope. The power of the lens is usually 10X or 15X. You can also change the eyepiece with a larger magnification value of about 25X to 30X.
It is the metal part that mechanically supports both the objectives and eyepiece lenses. It should be aligned in such a manner that both the lenses are present in one plane. Also, the length of the body tube is fixed; it's either 170 or 180 millimeters.
It is the part of the device that houses the primary lenses of the microscope - the objectives. Hence, it is located just above these lenses. The objectives are mounted on a revolving turret, so that one can conveniently select a specific lens, as per the requirements.
It is the curved part that connects the base of the compound microscope with the top portion. The purpose of this part is to support the body tube. For safe handling and picking up of the microscope, one hand supports the arm and the other supports the base.
These are the primary optical components of a microscope. As the name suggests, they are placed near the specimen. A typical compound microscope is constructed with 3 or 4 such lenses, having different magnifying powers, and ranging from 4X - 100X.
Stage and Stage Clips
The stage is a flat portion, where the specimen to be observed is placed on a slide. One can also use a mechanical stage for fine movements of the slide, if the device model supports this feature. Stage clips, on the other hand, are used for fixing the slide at a particular position.
It is installed just underneath the stage in a compound microscope. Also called an 'iris', it is an adjustable, rotating disk with different-sized holes. Its function is to adjust the size, as well as the intensity of light, which is focused on the slide from below.
Coarse and Fine Adjustment Knobs
They are basically used for the purpose of focusing on the object. The coarse adjustment knob is used for quick movement of the body tube and the stage, whereas the fine one is for precise and minute focusing of the object.
The function of this lens is to collect and focus visible light to the object in the slide. It increases the clarity of the image to a certain extent, particularly while viewing the specimen with more than 400X magnification. Based on the model, a compound microscope may or may not support such a lens.
It represents the bottom portion of the compound microscope. In some models, an artificial light source called illuminator (about 110 volts) is located at the base. This portion also supports the weight of the device.
For a better understanding, refer to the aforementioned diagram of labeled parts of a microscope. Handling the microscope roughly and/or improper maintenance may reduce the clarity of the magnified image. Hence, while using a compound microscope, always refer to the guidelines as mentioned in the user instructions.