SIMPLE MICROSCOPE: HISTORY, PARTS, FUNCTIONS, ADVANTAGES - CHEMISTRY - 2025

The simple microscope is an optical instrument that uses a single lens to magnify an image. Therefore, its ability to increase the size of objects is relatively low (10x). An example of this instrument is a magnifying glass.

This means that the image size of the objects is 10 times larger than the objects themselves. To solve this problem, the man used two lenses for the construction of the compound microscopes, with greater magnification capacity for the images of the objects.

Loupes are simple microscopes. Source: Pixabay.

The simple microscope had little evolution, as well as applications, in the first 12 centuries of our era. But from the 12th century, with the advent of glasses or spectacles, it managed to become a versatile element that could be used by man in many activities.

What is the simple microscope used for?

This instrument is used in the form of glasses for the correction of visual defects, such as myopia and hyperopia. It is also used by jewelers and watchmakers for the fulfillment of their work.

While jewelers use this microscope to enhance the perfection of gemstones, dermatologists use it to examine the health of the skin. Naturists and biologists, for their part, use it to study fresh waters, soils, seeds, flowers, leaves, insects, etc.

A remarkable fact in microscopy is the creation by Leeuwenhoek (1673) of a simple microscope with a high magnification capacity (275 x), which allowed him to microscopically observe various types of cells.

Leeuwenhoek also managed to observe the first microscopic living things, such as protozoa and bacteria. Likewise, Robert Brown with the use of a simple microscope was able to identify the cell nucleus.

History

The first lenses

The oldest known lens is the Nimrud lens, built in the Assyrian Empire, around 750 BC.

The first written mention of magnifying glasses appears in Aristophanes' comedy, called "The Clouds", exhibited in 65 AD. The same year, the philosopher Seneca exposes the properties of lenses in his encyclopedia "Natural Questiones".

The Romans in the 1st century AD built glass that was thicker in the center and thinner at the edge. When looking through the glasses (lenses), they noticed that the objects looked larger.

The word 'lens' comes from the Latin word 'lentil', due to the similarity of shape between the lens and the grain. Lenses were of little use until the late 13th century, when they were used in large numbers for the production of glasses. These are simple microscopes known as magnifying glasses.

First compound microscope

In 1590 the first compound microscope was built, attributed to Hans Lippershey, a manufacturer of glasses, and to Zacarias Janssen and Hans Janssen, who worked on circus shows. Other authors identify Cornelis Drebbel (1619) as the inventor of the compound microscope.

Hans Lippershey. Source: Jacob van Meurs, via Wikimedia Commons.

The compound microscope consisted of an ocular lens and an objective lens, placed in a tube made of wood. A drawing made in the Netherlands in 1631 clearly shows that the microscope invented by the aforementioned authors was a compound microscope.

Robert Hook published in 1665 the book Micrographia, where he exposed the observations made with a compound microscope made by himself. Hook made observations of corks, noting the presence of structures similar to those found in a honeycomb which he called cells.

Galileo Galilei (1610) discovered how he could observe small objects through his telescope. He built a compound microscope, based on the one built by Drebbel, and managed to attach a focusing mechanism to it.

Antonie van Leeuwenhoek (1632-1723) achieved, through glass polishing, the production of lenses of small size and large curvature, so they could be considered as spherical lenses. The lenses used by Leeuwenhoek in his simple microscope had a magnification of up to 270 x.

Leeuwenhoek Microscope

In Leeuwenhoek's simple microscope, the lens was inserted into two holes in the plates that served as support. The sample to be observed was placed using needles manipulated by a screw.

Leeuwenhoek, using his simple microscope, was able to observe blood cells, sperm, and bacteria; the first microscopic organisms that could be observed. This fact led to Leeuwenhoek being called “The Father of Microscopy.

Leeeuwenhoek's microscope could show details down to 0.7 µ, allowing him to study freshwater microorganisms. While plain lenses on plain microscopes can present detailed images, colors can be inaccurate.

This is explained by the existence of chromatic aberration, which indicates that different wavelengths (colors) have different foci. Chester Moor Hall found that the proper combination of a convex lens and a concave lens can correct chromatic aberration to some degree.

In the first half of the 19th century Robert Brown, using a simple microscope, managed to discover the cell nucleus, as well as a random movement of the particles that was named in his honor Brownian movement. Brown used microscopes built by Robert Bancks in his observations.

Parts

The virtual image created by the simple microscope lens is larger than the real object

A simple microscope consists of only one converging lens, known as a magnifying glass. The lens can be framed in a bracket, which in the case of glasses is known as the lens frame.

Leeuwenhoek designed a holder for his lens consisting of two sheets. Additionally, the scientist designed a mechanism for the placement of the sample to be observed.

Features

The simple microscope (magnifying glass) fulfills numerous functions or applications in different areas of human activity.

Numismatics and philately

The magnifying glasses are used to observe the characteristics and state of the coins, as well as the state of conservation of the postage stamps. They are not only used to verify their quality, but also in order to detect any anomaly in the production of the stamp that translates into an increase in its value.

biology

Magnifying glasses are used to observe the characteristics of species of insects, arachnids, plants, etc., which allow their identification and classification. In the genetic crosses of the Drosophila melanogaster fly, the magnifying glass is used to identify the phenotypes that are used.

Medicine

Ophthalmologists use different types of lenses to correct vision defects in patients: myopia is corrected with biconcave lenses; hyperopia with biconvex lenses, and astigmatism with cylindrical lenses.

Dermatologists use loupes to study abnormalities on the patient's skin; for example, the shape of moles, the presence of abnormalities of the scalp, etc.

Jewelry

Precious stones must be subjected to a carving process that increases their perfection and value; they get brighter. The magnifying glass is used in this activity and in some related to the treatment of precious stones.

Painting

Painting experts use the magnifying glass to determine the condition of paintings. In addition, it helps them to identify if a work belongs to a certain painter, based on the lines used in their paintings, the technique followed, and the type of pigments and colors used.

Watchmaking

Watchmakers use the magnifying glass to visualize the status of watch parts that need repair and replacement, since these parts are small in size and cannot be viewed for manipulation with the naked eye.

Advantage

First

The manufacture of a simple microscope is less expensive than that of the more elaborate microscopes.

Second

The simple microscope can be used in field work, such as the detection of protozoa in fresh water or the study of the morphological characteristics of the soil.

Third

The simple microscope is very versatile and fulfills many functions. Thus we see its use in glasses or spectacles that allow the reading of newspapers and books.

Quarter

Chromatic and spherical aberrations in simple microscopes were less than those existing in the first compound microscopes; before proper operation of the objective lens and eyepiece was achieved to eliminate aberrations. On the other hand, simple microscopes have higher luminosity.

Fifth

The use of glass microspheres, present in reflective paints, has allowed the construction of simple microscopes that have a magnification greater than 400 x. This has allowed the observation of erythrocytes and leukocytes in human blood with hematoxylin-eosin staining.

The photos of the observation with the simple microscope with microspheres and a modern microscope of the blood cells, indicate that there is not much difference in the resolution obtained with both microscopes.

Disadvantages

First

Simple microscopes have little ability to increase the size of object images, compared to compound microscopes, due to their focal length. However, Leeuwenhoek managed to produce small, nearly spherical lenses capable of 275x magnification.

Second

Simple microscopes often show chromatic and spherical aberrations.

References

1. Alejandro del Mazo Vivar. (December 26, 2018). Simple microscope - much more than just a magnifying glass. Cadiz University. Recovered from: redalyc.org
2. Encyclopædia Britannica. (2020). History of Optical Microscopes. Recovered from: britannica.com
3. Microscope World. (2020). Microscope History: Who Invented the Microscope? Recovered from: microscopeworld.com
4. Wikipedia. (2020). Microscope. Recovered from: en.wikipedia.org
5. Microscope world. (2020). The simple microscope. Recovered from: mundomicroscopio.com
6. Sagar Aryal. (October 06, 2018). Simple Microscope: Principle, Instrumentation and Applications. Recovered from: microbenotes.com