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BEGINNER'S MICROSCOPY

What is Microscopy?
Microscopy refers to the study of and the use of microscopes. Microscopy is the technical field of using microscopes to view samples and objects that are too small to be seen with the unaided or normal eye. In order to use microscopes effectively, safely and to achieve desired results it is important to know the microscope to use for the specific work and the workings of its component parts. This is why users of microscopes even at the elementary levels must be exposed to the operational principles and practice of microscopy.

There are three branches of microscopy namely:

1.      Optical microscopy

2.      Electron microscopy and

3.      Scanning probe microscopy

For routine biological at first year undergraduate level in Nigeria we will be concerned mainly with optical micrscopy. Optical micrscopy operates by the diffreaction, reflection or refraction of electromagnetic radiation (light rays) interacting with the specimen to be observed or studied.

Optical Microscopy through the ages

Microscopy has developed throught the ages and this development has revolutionized the understanding of the field of biology and it has become an essential technique in the life sciences including medicine, zoology, botany, microbiology, and so on as well as the physical sciences.

The following are personalities with profound contributions to the development of microscopy through the ages.

1. Hans and Zacharias Janssen  

The development of the first microscope is usually credited to Zacharias Janssen, in Middleburg, Holland, around the year 1595. Since Zacharias was very young at that time, it is believed that his father, Hans made the first one, but young Zacharias later took over the production of the micrscope his father made. The first compound microscope produced by the Janssens was simply a tube with lenses at each end. The magnification of these early scopes ranged from X3 to X9, depending on the size of the diaphragm openings. For further reading follow this link:
http://www.history-of-the-microscope.org/hans-and-zacharias-jansen-microscope-history.php

 

2. Robert Hooke

Hooke improved on early compound microscopes around 1660. In his book titled Micrographia published in 1665, he coined the word cell to describe the features of plant tissue (cork from the bark of an oak tree) he was able to discover under the microscope.  For more about Hooke follow this link: http://www.nndb.com/people/356/000087095/

 

3. Anton van Leeuwenhoek

Leeuwenhoek made simple (one lens) microscopes. Although he was not the first person to build a microscope,  the ones he built were the best ones for that time. Leeuwenhoek was the first person to describe bacteria from teeth scrapings and protozoans from pond water. He gained much of his inspiration from reading Hooke's Micrographia.

Read more here: http://www.essentialvermeer.com/dutch-painters/dutch_art/leeuwenhoek.html

 

Compound Light Microscope:

This is a type of micrscope used for routine biology work for general teaching and learning about micrscope use. It is suitable for studiying morphological features of specimens at the organismal level of biological organisation. The term light refers to the method by which light transmits the image to your eye. Compound deals with the microscope having more than one lens. Microscope is the combination of two words; "micro" meaning small and "scope" meaning view.

 

Early microscopes, like Leeuwenhoek's, were called simple because they only had one lens. Simple scopes work like magnifying glasses. These early microscopes had limitations to the amount of magnification no matter how they were constructed. The creation of the compound microscope by the Janssens helped to advance the field of biology. The Janssens added a second lens to magnify the image of the primary (or first) lens. In contrast to simple light microscopes  that only magnified an object to 266X as in the case of Leeuwenhoek's microscope, modern compound light microscopes, under optimal conditions, can magnify an object from 1000X to 2000X (times) the specimen’s original diameter. This is a greatly improved efficiency!
Below is a diagram showing the parts of a compound light microscope.

HOW A MICROSCOPE WORKS
The digrame below is a schematic diagram showing how a compound light microscope works.