What Is A Microscope Used For In Science?

A microscope is an instrument that can be used to observe small objects, even cells. The image of an object is magnified through at least one lens in the microscope. This lens bends light toward the eye and makes an object appear larger than it actually is. Microscopes are used to magnify and observe tiny objects, organisms, and structures that are too small to be seen with the naked eye, allowing scientists and students to explore and understand the microscopic world.

How Light Microscopes Work

Light microscopes are essential scientific instruments that allow us to see objects too small for the naked eye. These powerful tools use a series of lenses to magnify tiny specimens, revealing intricate details of cells, microorganisms, and tiny structures that would otherwise remain invisible. In a typical light microscope, light passes through or reflects off a specimen, travels through objective lenses and eyepiece lenses that further enlarge the image. This enables students and scientists to observe specimens at magnifications typically ranging from 40x to 1000x, opening up an entirely new world of observation.

The magnification of the objective lens can vary. Compound microscopes can have up to four objective lenses of different magnifications, and the microscope can be adjusted to choose the magnification that best suits the viewer's needs. The total magnification that a certain combination of lenses provides is determined by multiplying the magnifications of the eyepiece and the objective lens being used. For example, if both the eyepiece and the objective lens magnify an object ten times, the object would appear one hundred times larger.

Types of Microscopes and Their Characteristics

There are two common types of microscopes used in laboratories: the compound light microscope and the stereo microscope (commonly known as a dissecting microscope).

Compound Light Microscope

A light microscope is used to visualize objects flattened onto glass slides in great detail. It typically has a magnification power of up to 1000x. It is typically used for observing objects at the cellular level, such as examining individual cells within living tissue.

Dissecting (Stereo) Microscope

A dissecting microscope is used to view three-dimensional objects and larger specimens, with a maximum magnification of 100x. The dissecting microscope provides a lower magnification than the compound microscope, but produces a three-dimensional image. This makes it good for viewing objects that are larger than a few cells but too small to see in detail with the human eye, or to examine structures not easily mounted onto flat slides.

Scanning Electron Microscopes

Scanning electron microscopes have magnifications up to several million times to view the molecules, the viruses, and the nano-particles. They use corrective software to increase the magnification and the resolution of images. Electrons, x-rays, and infrared rays scanning electron microscopes are able to resolve the viruses which are far smaller than any cell.

The following table summarizes the resolution and working principles of microscope types:

Traditional Optical Microscope

Resolution: 0.2 µm — Works on optical principle in atmospheric environment.

Fluorescence Microscope

Resolution: 0.2 µm — Uses fluorescence of the sample to be measured using UV excitation in atmospheric environment.

Laser Confocal Scanning Microscope

Resolution: 0.12 µm — Based on laser scanning in atmospheric environment.

Transmission Electron Microscope

Resolution: 0.2 nm — Collects transmission electrons for imaging in vacuum environment.

Scanning Electron Microscope

Resolution: 1 nm — Collects secondary electrons for imaging in vacuum environment.

Atomic Force Microscope

Resolution: 0.1 nm — Detects changes in atomic forces on the surface of the object using a probe in vacuum environment.

Specimens Examined with a Light Microscope

Light microscopes are versatile tools used to examine a wide variety of specimens. Common uses include:

• Prepared slides of plant and animal tissues, revealing cellular structures like cell walls, nuclei, and chloroplasts
• Microorganisms in pond water samples, including algae, amoebas, and paramecia
• Blood smears to see different types of blood cells
• Insect parts and insect wings to study their intricate patterns
• Textile fibers and thin sections of rocks and minerals
• Everyday items like salt crystals or human hair
• Crystalline structures of minerals

The light microscope is ideal for viewing any specimen that is thin enough for light to pass through or that can be illuminated from above.

Use of Microscopes in Biology

When it comes to biology, microscopes are important because biology mainly deals with the study of cells (and their contents), genes, and all organisms. Some organisms are so small that they can only be seen by using magnifications of 40x–1000x, which can only be achieved with the use of a microscope. Cells are too small to be seen with the naked eye.

By using microscopes, scientists, researchers, and students were able to discover the existence of microorganisms, study the structure of cells, and see the smallest parts of plants, animals, and fungi. By making the invisible visible, microscopes have allowed scientists to develop cell theory, understand disease-causing microorganisms, and make countless discoveries that have advanced human knowledge. All branches of biology use microscopes, especially in molecular biology and histology (the study of cells). The biologists use them to view the details that cannot be seen by the naked eye such as small parasites and small organisms, which is important for disease control research.

Medical and Clinical Applications

Microscopes are also used to diagnose illness in hospitals and clinics all over the world. Microscopes magnify the blood samples so the doctors or the pathologist can see the viruses and the parasites attacking the red blood cells and take the necessary steps to cure it. Microscopic examination confirms the laboratory tests that may be positive for the disease. Technicians count the number of red blood cells infected with the virus or parasite to give the doctors an idea of how advanced the disease is in a patient.

Scanning electron microscopes enlarge the view of tiny viruses, which allows scientists to develop the vaccines and cures for infectious diseases in humans and animals. The computers help the nano-technologists use high-powered electron microscopes to view the objects.

Industrial and Technological Applications

Microscopes are not just used to observe cells and their structure but are also used in many industries. The following are key industrial applications:

1. Electron microscopes help create and observe extremely tiny electrical circuits found on silicon microchips.
2. Electron microscopes help prepare the small surfaces for sectioning into small slices.
3. Microscopes enlarge the images of silicon chips to help the engineers create more efficient electronic devices. When more circuits are fitted onto a small chip, the computational power of silicon microchips increases.
4. Scanning microscopes are much more sophisticated and they have higher magnifications than light-refracting microscopes.

Use of Microscopes in Genetics

Apart from biological research use and industrial use, microscopes are also used in the field of genetics. Genetics is the study of variations in an organism generation after generation. Genetic engineering requires the mixing of genes. Genes are even smaller than cells, which is why microscopes are essential in this field. Without the microscope, mankind would not have been so developed and many diseases would still have no cure.