How Does a Microscope Work?


One of the most common lab equipment is the microscope. As a child, we wander through scientific laboratories and always find one of these. As we see these, we cannot help but ask ourselves: “How do microscopes work?” 

A microscope. It is a great tool that led to great scientific breakthroughs throughout the ages, more especially in the field of medicine. However, outside labs come with the simplest of microscopes, which are single microscopes. A simple microscope usually has one lens that usually plays as a magnifying glass, with relatively high magnification. 

Labeled Microscope Parts

While simple microscopes are more basic to use, the masses needed some more complexity to yield better results. This is the reason why compound microscopes are usually seen inside schools, hospitals, and research centers, and laboratories. The compound microscope has a series of lenses made specifically to collect and focus light to transmit through the specimen. It may be more complex and larger than simple microscopes, the compound microscope provides increased magnification and resolution levels and reduces chromatic aberration all at the same time.

As continuous advancement was made to laboratory equipment to yield better results, more and more specialized microscopes were created to give accurate results on the field they are made to specialize in. An electron microscope, for example, is a microscope that uses electrons as a source of illumination. Although it operates differently, it still uses the same scientific principles as its conventional counterparts.

The Anatomy of an Optical Microscope

Like any other device, discussing its different parts will help us fully understand how microscopes work. It is essential to know every role each part play, as they are the ones that compromise the equipment.

Before jumping in on each part, the most simplistic way to describe a microscope is that it is a tool made to contain lenses and can serve as a platform for stable viewing of specimens and other applications that need image quality improvements.

Parts of the Microscope

The Lenses– The lenses are simply the heart of the microscope. A microscope will simply not work without proper lenses, to begin with. These are the parts that enable the microscope to magnify and view the image at a closer and larger scale. 

Usually, compound microscopes have two or more lenses, compared to simple microscopes which only have one. This provides an edge for compound microscopes, as they are built to accomplish more advanced tasks. Its eyepiece, also called the ocular lens, sits at the top of the body tube. This is the most common type of microscope, as it can do a wide variety of tasks, from simple to complex. 

Moreover, the head of its binocular will have a prism, either placed at the head or body, causing the image to split and be redirected through both oculars. The oculars usually have different magnifications, but it is usually less than the magnification that objective lenses can offer.

The objective lenses are placed at the bottom of the microscope tube. They are the lenses that are nearest to the specimen, as they are made to gather and focus light transmitted from the specimen.

Usually, there are more than three to four objective lenses with each different strength. They are usually found on a revolving turret. To change the magnification, the revolving turret must be turned to line up a different lens with the body tube. These lenses usually have magnification strength ranging from 10 to 100x. You can adjust the fine and coarse focusing by the focusing knobs, located at the body of the microscope. 

The Stage– This is the part where the specimen sits, just below the objective lenses. To hold them firmly, clips are made and placed on the stage to hold the specimen, enabling a better and more stable viewing experience. 

The mechanical stage is a stage that you can move and adjust. It is made to allow the viewer to move the specimen along the X and Y coordinates, while the graduated markers scribbled on it allow the viewer to have a note of the location of features on the slide. Lastly, a hole is placed under the stage to allow light to pass through the specimen for better viewing.

The Light– Just below the main platform, a condenser, a diaphragm, and the light source controls the amount of light that is emitted, and the viewing of the specimen. The illumination source is usually found at the bottom of the optical tray. 

The type of source where illumination comes from will enable sophistication to increase, as the microscope’s complexity increases as well. Different light sources may also yield different results for a wider scope of the experiment. The most common light sources include Tungsten-halogen, mercury arc, as well as LED illumination. 

Some microscopes have a condenser lens sitting right above the light source. This condenser is built to gather light and focus it into a cone shape, emitting the light directly to the specimen. To control the diameter of the light beam before passing through the specimen, the viewer can always adjust the diaphragm. 

Optical Use of Microscopes

Generally, microscopes have three general missions to accomplish: To magnify the specimen, to resolve the details of the specimen, and to make every detail visible to our eyes. 

Understanding these things first is essential in finding out how microscopes work. The light or optical microscopes are built to use visible light and manipulate it by transmitting it through, refracting it around, or reflecting it from the specimen.

Magnification Use of Microscope

Magnification is the power of a lens to magnify and make images look bigger. It is dependent on how many lenses can bend the light waves. Magnification is often measured by numerical multipliers. When it has “2x” indicated on it, it will possibly double the image size of the item you are viewing through the microscope.

But when it comes to a compound microscope, the magnification value might be different, and it is often much powerful. When finding out the total magnification, you must multiply the value of the ocular lens with the magnification level of the main objective lens.