Have you ever wondered what the most minor things look like up close? From one grain of sugar in your coffee, a strand of hair, or your cheek cells, you can’t see these things and examine them closely with just your naked eye. If these items are already challenging to inspect, what of the smaller parts of an organism and other things that seem almost invisible? This is what microscopes are for.
What Is A Microscope?
A microscope, from the Ancient Greek words mikrós or “small” and skopeîn or “to look or see,” is a tool that is used to view smaller objects that the human eye can see. Microscopy is the scientific field of study which is used to study minute structures and objects by a microscope.
In the 16th century, Zacharias Janssen discovered and credited the first compound microscope. By placing an object at the end of a tube and two lenses on top and bottom of the tube, Zacharias and his father, Hans, realized that the object became magnified. Thanks to this discovery, more breakthroughs and innovations were developed that led to the microscopes we use today.
How Do Microscopes Work?
The most basic microscopes used in various institutions today use a series of lenses that collect, reflect, and focus light into the specimen, which is the object under inspection. Without the presence of light, microscopes won’t work. This kind of microscope is typically used in research centers, schools, and hospitals.
The use of different microscope lenses promotes magnification without altering the quality of the image produced. Aside from the lens magnification, it’s also important to identify the microscope field of view to accurately measure the size of your specimen. Also, most microscopes have binocular lenses consisting of two lenses and a prism to split the image on both oculars, where you’ll peek through.
On another end of the microscope are objective lenses which are responsible for collecting and concentrating light into the specimen. These objective lenses have varying strengths which can be used one at a time by adjusting the revolving nosepiece.
Modern Microscope Eyepieces
An essential component of every microscope is the eyepiece, also known as the ocular lens, which magnifies the image produced by the microscope’s objective lenses. Modern microscopes primarily utilize three common types of eyepieces: the Huygenian, Ramsden, and Wide-field eyepieces.
The Huygenian eyepiece is among the simplest and oldest designs still in use today. It comprises two plano-convex lenses oriented in the same direction, with their convex sides facing the specimen. This eyepiece provides adequate clarity for general educational purposes and routine laboratory observations, typically found in basic microscopes used in schools.
The Ramsden eyepiece is another traditional design composed of two plano-convex lenses, but unlike the Huygenian, these lenses are arranged facing each other, separated by a small gap. This design significantly reduces optical aberrations and enhances the overall image quality, making it suitable for precision observations and detailed laboratory research.
More advanced microscopes employ Wide-field (WF) eyepieces, which are favored for their superior image quality and comfort. Wide-field eyepieces contain multiple lens elements that enable users to view a much larger area of the specimen at once. This enhanced field of view facilitates easier scanning and observation of samples, significantly improving the user experience during extended microscopy sessions. Wide-field eyepieces are particularly beneficial for complex biological samples, medical diagnostics, and detailed research applications.
Selecting the appropriate eyepiece type depends on your specific microscopy needs. Basic educational settings commonly utilize Huygenian eyepieces, while professional laboratories and research institutions generally prefer Ramsden or Wide-field eyepieces for their superior optical performance and viewing comfort.
Other types of eyepieces exist and are used depending on the needs of the experiment being conducted. By learning how a microscope works, researchers will be able to use these eyepieces in their experiments, thus providing better ways to study nature and its workings.
Microscopes are usually powered by batteries or by mechanical mechanisms to allow the observation of objects up to 10 times smaller than their original size. If a microscopic specimen is not handled correctly or in an inappropriate way, it can distort the image and give misleading results. Therefore, using the right type of microscope and handling it properly is important for viewing your chosen object.
Here are five types of microscopes, their specific qualities, and uses:
Simple Microscope
A simple microscope is simply a large magnifying glass with a shorter focal length that has a convex mirror with a small focal area. The most common examples of this type of device are the handheld lens and eyepiece lens.
When a material is held close to the lens of the microscope, its focus is created, and the original object becomes magnified and more erect. Then, it focuses on a portion of the material by bringing together the two edges of the lens. This creates a smaller, more focused image of the material than the larger area.
Since it’s only a simple microscope, it only has one magnification level depending on what lens is used. Therefore, simple microscopes are only used for reading and magnifying non-complex items. For instance, you can use a magnifying glass to zoom in the details of a map.
Compound Light Microscope
A compound microscope is the most common type of microscope used today, which mechanism is explained earlier. It is basically a microscope that has a lens or a camera on it that has a compound medium in between. This compound medium allows for magnifications in a very fine scale.
While the simple microscope only requires natural light to see the object, a compound light microscope needs an illuminator to view the specimen. These are the basic specifications of a compound microscope:
- Magnification: This pertains to making the specimen look larger through the microscope through zooming in the lenses. Magnification is a quantified property which ranges from 40x, 100x, 400x, and up to 1000x.
- Resolution: This refers to how good the image is captured by the compound microscope lens. A higher resolution means that the image will be clearer and more detailed. Also, it has an improved visual clarity as it has more layers of magnifications.
- Contrast: Like in photography, the background’s darkness relative to the focus or specimen is referred to as contrast. Excellent contrast is typically achieved through staining the specimen so its colors would stand out when viewed in the microscope.
Compound microscopes are extremely useful for research on different areas. It has made a big impact on science and technology in general. Some of its popular uses are when viewing a scientific specimen for educational and research purposes. If you’re looking into studying in medical school, you’ll often encounter this type of microscope in your classes.
Stereo Microscope
The stereo microscope, dissecting or stereoscopic microscope, is an optical microscopy version designed specifically for low magnification imaging of a biological specimen. It works through reflecting light off the specimen’s surface rather than transmitted through its medium.
This type of microscope is often used in chemistry laboratories where more detailed, three-dimensional images are required that would be possible with an electron microscope or other high-powered microscope. While the stereo microscopy technology has existed for over 100 years, stereo microscopes only recently have come into being in the laboratory and can produce higher quality images than ever before.
Many people choose stereoscopes over other microscope models because it can produce better quality images depending on one’s needs. In addition, these microscope models require less maintenance and are inexpensive. Stereo microscope applications involve less thorough microscopic requirements, such as viewing manufacturing materials, circuit board work, dissection, and inspection.
Scanning Electron Microscope (SEM)
A scanning electron microscope is a very popular type of scanning electron microscopes, which produces images of a material by scanning the sample with a high-powered beam of electrons. The electrons interacting with atoms within the sample create different signals which contain data about the structure and topography of the material. The images that are produced using these microscope instruments are highly accurate as well as they can be viewed in high resolution using a microscope eyepiece or magnifier.
To obtain appropriate results from an SEM, the sample or specimen should have electrical conduction for the electrons to bounce off on its surface, thus producing a clear image. For the sample to become electrically conductive enough, they’re coated in a thin layer of metals like gold.
Several techniques can be employed to enhance the image quality of SEM, such as: fluorescence imaging, tip electron microscopy, multi-beam scanning and the use of colloidal crystals.
Additionally, it’s important to use the microscope in good working condition as this will reduce the quality of images that you receive. With all these things in place, you can have a great instrument that will allow you to view and examine the smallest sample possible.
Listed below are the best applications and uses of a scanning electron microscope:
- Semiconductor inspection
- Materials science
- Medical science
- Forensic investigation
- Soil and rock sampling
- Nanowires for gas sensing
- Art
Transmission Electron Microscope (TEM)
Transmission electron microscopy is an optical microscopy method in which an electrical beam of electrons is transmitted through an unstained sample to create an optical image of the sample. Instead of sending electrons to scan and bounce off the specimen as what SEMs do, TEMs allow the electrons to pass through the thin sample. The sample is usually an ultrathin slice less than 50 micrometers thick or an electrolyte suspension suspended on a grid of grid-like plates.
In contrast to ordinary compound microscopes, TEMs have amazing magnification that’s possibly 10,000 times more than what optical microscopes do, allowing researchers to view exceptionally small specimens. It can even illustrate the arrangement of the atoms within a sample.
Because of the sophistication of TEMs, they’re extremely technical and expensive. Students usually don’t have access to this type of microscope as they’re for scientists doing demanding work involving the field of nanotechnology, medical research, life sciences, biological research, material research, gemology, and metallurgy.
However, the samples require detailed preparation where it must be placed in a vacuum chamber. Thus, living samples such as protozoa can’t be examined under TEM. while the samples can be stained or coated with chemicals to protect their structure, there are higher chances that the microscope will still destroy the sample. Despite these drawbacks, the contributions of transmission electron microscopes are unrivaled.
Modern Applications and Importance of Microscopes in Scientific Research
Microscopes remain fundamental tools across scientific disciplines, enabling breakthroughs in medicine, biology, materials science, and environmental research. While their primary role in magnifying tiny objects remains unchanged, their applications have vastly expanded, reflecting advancements in research methodologies.
In medicine and biological research, microscopes are instrumental in diagnosing diseases and understanding pathogens. Pathologists regularly use compound and electron microscopes to identify cellular abnormalities, facilitating early diagnosis of conditions such as cancer, blood disorders, and infections. Electron microscopy proved essential in visualizing the SARS-CoV-2 virus, allowing scientists to understand its structure and enabling the rapid development of vaccines. Microscopy has thus become integral to public health management and disease control strategies worldwide.
Environmental scientists employ microscopes to monitor ecosystems at a microscopic level. Algae, bacteria, and microorganisms within soil and water samples indicate ecological health. By studying these organisms closely, researchers gain insights into biodiversity, pollution levels, and ecosystem dynamics. Such observations support critical decisions about environmental conservation, pollution management, and climate change mitigation strategies.
Materials science and engineering are additional fields where microscopes have significantly impacted innovation and quality control. Electron microscopes, specifically SEM and TEM, allow researchers to analyze material structures down to the atomic level. This capability is crucial in developing new, advanced materials with properties optimized for strength, durability, and conductivity. For example, microscopy has advanced the creation of stronger and lighter alloys used in aerospace engineering, more efficient semiconductors for computing, and novel biomedical materials for prosthetics and implants.
Microscopes also play a vital role in pharmaceutical research and quality assurance. Compound and electron microscopes help scientists visualize drug formulations, verifying consistency and purity. Pharmaceutical companies extensively use microscopy during drug development to analyze crystal structures, detect contaminants, and ensure uniform drug delivery methods. This meticulous approach ensures the safety and effectiveness of medicines reaching the market.
Forensic science heavily relies on microscopy to uncover critical evidence. Forensic investigators utilize stereo microscopes and SEM to closely examine trace materials such as fibers, hair, and gunshot residues. Detailed microscopic analysis provides definitive insights, helping to solve crimes and deliver justice. The capability to identify microscopic evidence has revolutionized criminal investigations, providing greater accuracy and reliability in forensic conclusions.
Educational institutions continue to benefit immensely from microscopy. Beyond traditional laboratory settings, virtual microscopy enables remote, interactive learning, allowing students worldwide to examine digitized slides and high-resolution images without physical microscopes. This has democratized access to quality science education, fostering broader scientific curiosity and understanding across diverse populations.
Microscopes’ versatility continues to drive scientific advancements, influencing numerous fields and benefiting society. These instruments magnify the smallest details and amplify human knowledge, innovation, and well-being.
In countless ways possible, microscopes have so many to offer science. Studies and learning requiring object magnification can be executed properly thanks to microscopes. Microscopes also lay the groundwork for more scientific developments to come. As the world’s understanding of technology increases, it might only take some time before microscopes transform into new types with even more potential than what are present today.
