Early Microscopists saw quite distorted images due to the low quality of the glasses and imperfect shape of their lenses. Dramatic progress in the development of microscopes took place during the 19th century. In order for light microscopes to achieve better resolution, three basic problems had to be over come. (1) The first problem was the unequal bending of different colors of light that occur in lenses. (2) is the unequal bending of light that hits different parts of a lens . (3) For a microscope to be as good as physically possible it must collect core of light that is as wide as possible.
Various microscopists and further research lead to the development of the light microscope solved these problems.
Electron microscopes function exactly as the optical microscope except that they use a focused beam of electrons instead of light to ‘ image ‘ the specimen and gain information as to its structure and components. Electron microscopes (EM) were developed due to the limitations of light microscopes, which are limited, by magnification and resolution. In the early 1930s there was a desire to see the fine detail of the interior structure of organic cells. This required 10, 000 x plus magnification which was just not possible using light microscopes.
Electron microscopes are scientific instrument that use a beam of highly energetic electrons to examine objects on a very fine scale. The EM has several features in providing us with a greater understanding of cellular structure;
Topography;
The surface features of n object or ‘ how it looks ‘, the texture, direct relation between these features and materials properties (hardness, reflectivity..Etc)
Morphology;
The shape and size of the particle making up the object, direct relation between these structures and materials properties (ductility, strength, reactivity … etc )
Composition;
The elements and compounds that all objects is composed of and the relative amounts of them, direct relationship between composition and materials properties (melting point, reactivity, hardness … etc)
Crystallographic information;
How the atoms are arranged in the object; direct relation between these arrangements and materials properties (conductivity, electrical properties, strength. Etc)
These features are present in electron microscopes and help scientist to discover and understand the complex structure of the cell. As one can see each feature is very complex yet it is this, which allows us so much in depth detail.
SEM stands for scanning electron microscope. The SEM is a microscope that uses electrons instead of light to form an image. Since their development in the 1950s SEM have opened new areas of studies. The SEM has allowed researchers to examine a much bigger variety of specimens.
The SEM has many advantages over traditional microscopes. The SEM has a large depth of field, which allows more of a specimen to be in focus at one time. The SEM also has a much higher resolution, so closely spread specimen can be magnified at much higher levels. Because the SEM uses electromagnets more control is the accuracy of magnification.
The transmission Electron Microscope (TEM) was the first type of electron microscope to be developed and is similar to the light microscope, except that it focuses beam of electrons instead of light to ‘ see through ‘ the specimen, where as the beam of electrons are absorbed by the scanning electro microscope resulting in a 3d image.
Both SEM and Tem differ in the feature they pose. ;
From the diagrams and features it can be seen that both SEM and TEM differ in the way they interpret images to the human eye, it is because of this difference that allows us to view specimens with in a range of ways..
The research I have included through this assignment has increased my in depth understanding of microscopes over all, I enjoyed researching all aspects of the project and I’m sure ill find it will enhance my knowledge of microscopes in future . .
