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Microscopes are used to show the internal structure of materials. They also give biologists/ physicist the power to magnify and distinguish objects that are not visible by the human eye.

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Introduction

Microscopes How can we find out the structure of several materials? For instance wood, the grains of wood reveal its structure. But there are certain materials where the structure cannot be seen by the human eye or felt. For example a coin or a piece of rubber will appear "smooth" to the naked eye. Microscopes are used to show the internal structure of materials. They also give biologists/ physicist the power to magnify and distinguish objects that are not visible by the human eye. Light microscopes have improved the knowledge in biology, biomedical research and materials science. Light microscopes can magnify objects up to 1,000 times, revealing microscopic details. The light microscope, so called because it allows visible light to detect small objects, is probably the most well known and well-used research tool in biology. ...read more.

Middle

Electron microscopes are scientific instruments that use a beam of highly energetic electrons to observe objects on a very fine scale. Electron microscopes have a focused beam of electrons instead of light to have a "image" of the object, and gain information of its structure and composition. How they work: 1. A stream of electrons is formed and accelerated towards the object using a positive electrical potential. 2. This stream is a thin focused monochromatic beam. 3. This beam is focused onto the sample using a magnetic lens. 4. The electron beam interacts with the sample, affecting its focus. Grass Hopper, viewed using an electron microscope It's not possible to see an electron beam, so the electron beam is projected on to a fluorescent screen so that the image can be viewed. ...read more.

Conclusion

A great depth of information is achieved, even using the same magnification and resolution as the light microscope such detail cannot be achieved because you would constantly have to keep on focusing up and down. The disadvantage of this is that it cannot have the same resolution as the TEM. The transmission electron microscope (TEM) works by passing a beam of electrons through the specimen before it was viewed. Electrons that passed through the specimen are seen. This means that thin sections of the specimen are seen, such as the insides if cells. The advantage light microscope over electron microscopes is its ability to observe living organisms and tissues. Various types of electron microscopes require the specimen to be coated with gold and placed in a vacuum chamber. What ever form of life is present will not survive under these conditions. Where as a light microscope allows once to observe living organisms. ...read more.

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