Uses of Microscope: Types, Parts, Applications

Microscope is an Optical Instrument used to see objects which are too small to be seen by the naked eye, using layers of magnifying lenses. The enlarged image can be formed by waveforms including X-ray, acoustic, or electron beam, and received by direct or digital imaging or by a combination of both methods. 

Key Takeaways: Magnifying power, Microscope, magnifying lense, Optical Instrument, waveform, X-ray, acoustic beam, electron beam

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Magnifying Power of Microscope

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A range of power in which the microscope enlarges the image of the object is the magnifying power. We express it using the following formula:

 M =tanθtanθ = angle subtended by the final image to the eye angle subtended by the object seen directly (dimensionless ratio)

Here,

tan β ≈ β

tan \(\alpha\) ≈\(\alpha\)

So, the magnifying power of the microscope formula is the ratio between the angle subtended by the final image to the eye, and the angle subtended by the object seen directly, provided that both of these are kept at minimum distance of distinct vision (-25 cm).

The above two cases are possible when the angles are very small. So, we rewrite the above equation as:

M=βα

Also, M _Total = M_objective  X M _Eyepiece

So, total magnification = magnification of objective * magnification of the eyepiece.

The video below explains this:

Compound Microscope Detailed Video Explanation:

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Types of Microscope

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Microscopes are of various kinds:

1. Simple Microscope
2. Compound Microscope
3. Darkfield Microscope
4. Electron Microscope
5. Fluorescence Microscope
6. Contrast/Phase Microscope

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Parts of Microscope

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The microscope is a complex instrument. Following are the main parts of a typical microscope:

Arm

It is located at the back of the microscope. It is used to carry the microscope and supports the objective and ocular lenses.

Base

The bottom of the microscope is called its base. It holds the light source and is also used to carry the microscope.

Coarse Focusing Knob

It is used to adjust the position of the objective lens. The adjustment should be done while keeping in mind that the objective lens must not hit the slide. It should be stopped when the specimen is completely visible through the ocular lens.

Fine Focusing Knob

It is used to bring the specimen in perfect focus, once it is visible through the coarse focusing knob. It should be focused slowly to avoid contact between the objective lens and the specimen.

Illuminator

It is also called the light source of the microscope.

Numerical Aperture/ Objective Lens

It is found only in a compound microscope and is the lens closest to the specimen.

Ocular Lens

It is found only in a compound microscope and is the lens closest to the viewer.

Oil Immersion Lens

It is also found in a compound microscope. It is an objective lens with 100x power. It is small in size in order to attain high resolution and magnification. Due to its size, it is important for the lens to get as much light as possible. By immersing the lens in oil, refraction of light is eliminated.

Given above is a simplified diagram of a microscope, with all its parts labeled for a better understanding of the location and function of each part,

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Uses of Microscope

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Microscopes are used in a wide range of activities both in day-to-day lives and in professional and educational fields. Some of the uses of microscopes are listed below.

In Pathology and Medicine

The greatest contribution of microscopes is in the field of healthcare. They are used to diagnose diseases by getting a larger view of the blood sample, making it easier to detect parasites, bacteria, etc. Researchers also use it to study harmful microorganisms and their effect on the human body, to find the cures for various diseases.

By Scientists

The microscope can be found in every biological laboratory and research center. They are used by scientists to study microorganisms, cells, crystalline structures and molecular structures.

In Forensic Science

In crime scenes, criminals usually erase proof of their identification. In such cases, microscopes help forensic doctors to examine organs, bones and other parts of the body to know the cause of death. They can also be used to simplify complex evidence.

Botanical Field

Botanists and lab professionals use microscopes to do research on various plants and fungi, to study the features of leaves, plant cells, etc.

In Education

Microscopes are found among various other optical instruments in every science laboratory in colleges, schools and universities. Because of its excellent usage, it is one of the most widely used devices among students.

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Things to Remember

• The science behind investigation using microscopes is called microscopy.
• The main purpose of a microscope is to interact with a sample and produce images by sending a beam of light or electrons through the sample’s optical path.
• The magnifying power of microscopes is called angular magnification.

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