Let us learn some interesting and important facts about a Compound Microscope. When you hear the word ‘compound microscope’, the image that often would pop up in your mind would be of an advanced microscope, which assists in visualizing specimens like bacteria and all kinds of living cells, at multiple magnifications. If so, you are absolutely right, then it would be appropriate to term this microscope a biological microscope. However, the only purpose of this magnification technology is not just visualizing Intra and intercellular structures through the cross-sections of biological cells.
How Does a Compound Microscope Work?
The compound microscope works on the principle of a light microscope, enabling the human eye to observe subjects that cannot be seen by the naked eye. But how does it make this possible? We will begin understanding its working phenomenon by discussing its parts step by step.
- Eye-piece: This magnifying lens is directed upwards, having close contact with the human eye. In other words, you can observe any minute object firstly by placing your eye adjacent to the eye-piece of the compound microscope. Its lens has a standard magnification power of 10x.
- Compound Lens System: This comprises a combination of 4 lenses of power 4x, 10x, 40x, and 100x. Each of these lenses is referred to as the ‘objective lens’ as the object to be viewed is placed on the stage part close to these lenses. These lenses are bonded to a nose-piece on the lower part of the Arm of the compound microscope, opposite to the position of the eye-piece. The nose-piece can revolve, serving the human eye with the opportunity to visualize samples at different magnifications.
The combined magnification power of the eye-piece and objective lens serves as an ideal medium to magnify the smallest details of the specimen. 40x is the minimum magnification power of the compound microscope while 1000x is the maximum (10x of the eye-piece multiplied with the maximum lens power of 100x of the objective lens).
- Stage: The specimen slide is placed on the stage, just below the objective lens system. The sample slide may or may not be stained, depending on the kind of compound microscope that you are using. Different dyes are used to stain the living cell and bacteria specimens for imaging different details, like Zeil Nelson stain. The stage also comprises clips to keep the sample slide fixed at one place for efficient visualization.
- Other parts: These parts are structures of this microscope below the level of the stage. They include Condenser, Illuminator, Coarse Focus, and Fine Focus. A switch to emit light from the Illuminator is situated on the lower side of the microscope.
When you place a slide sample on the Stage, connect the microscope’s wire with the power supply and switch the Illuminator button ‘on’. The Condenser condenses light from below in the direction of the slide. This aids in improving the clarity of your specimen’s image. You can use both the coarse and fine focus alternatively for fulfilling a similar purpose, which is the clarity of your vision.
Which other Compound Microscopes Exist apart from the Biological Microscopes?
You will not be wrong to say that every biological microscope is a compound microscope but not every compound microscope is a biological one. The interesting reality is that this microscope can be used to achieve some crucial objectives in the industry of chemicals and metals.
Other types of Compound Microscopes are
Phase Contrast Microscope
With this compound microscope, you do not need to stain your bacterial sample slides. It can visualize different details of a blood cell without any need for staining. It achieves this with the assistance of an exclusive phase-contrast objective lens or a phase condenser.
Polarizing Compound Microscope
This is used in the industrial setting to visualize chemicals, minerals, and small bits of rocks. It does this by detecting different colors in the optic pattern of the specimen being viewed.
As the name reveals, it is used to detect delicate cracks in metals and hardly noticeable defects in stones. As metals are opaque and do not allow light transmission, this compound microscope uses the technique of light reflection and illumination via the objective lens.
How a Dissecting Microscope is different from a Compound Microscope?
As its name suggests, a Dissecting or a Stereoscopic Microscope can play a very useful role in a science class where small creatures need to be visualized closely and clearly, and also need to be dissected for studying their details.
It can also be used in manufacturing small and intricate circuit boards like that of a watch, and also in microsurgeries. Unlike the compound microscope, it has a design of binocular or trinocular eye-piece lenses, which are situated at angles that produce different visual paths when light is emitted from the eyepieces. In contrast, a compound microscope emits light only via its Illuminator. Moreover, both its eye-pieces are designed at a parallel angle, therefore producing a single visual pathway.
Other Variations Include
- Transmission of light from the surface of the object viewed, rather than transmission through the object.
- The angled eye-pieces in combination with the objective lens produce a massive image of the object being viewed.
- Being a digital microscope, this image is mostly viewed on a computer screen. For this reason, this microscope is feasible to be used in a school setting, for example, to study the parts of the insect, dissect it, and qualitatively assess its dissecting surfaces.
- A dissecting microscope operates at a low magnification of 5x-250x.
- It produces 3D images of the objects being viewed.
This Stereomicroscope can also be connected to your cameras and tablets.