There are many different types of microscopes and each of them works in different ways and are used to magnify different things. Some examples of these are light microscopes, transmission electron microscopes and scanning electron microscopes. .
Light microscopes, also known as a compound microscope, are the most simple. The condenser focuses light rays, which normally come from a lamp pointed at the mirror. It focuses light onto the object to be viewed. Light travels through the specimen and up to two lenses, one of which forms the image while the other greatly magnifies it so that we are able to see the detail in the specimen. An important part of how the microscope works is the fact that light travels through the specimen. For this to take place, the material must be cut very thinly. The material is then stained so that the different parts of the material are visible. A dye such as methylene blue is used because this dyes the material without killing it. Other dyes require the material to be killed first.
An electron microscope is different to a light microscope. They have played an important part in our knowledge of the cell ultra structure. It shows us the fine details of the cell organelle. Electrons are used to make a magnified image of the cell. Electrons have a much shorter wavelength than light and so therefore it has a great resolving power. Instead of a lamp that was used with a light microscope to generate light an electron gun is used, which are then focused on electromagnets. Areas that are densely filled with electrons produce dark areas so we can clearly see the shape of the cells. The high-density electron beam can destroy parts of the tissue causing lighter parts on the image we see. The image produced is then seen on a screen or photographic plate. The photos of specimens produced are called electron micrographs. Electron microscopes cannot be used to look at living cells so the disadvantage of this is that the cells have to be killed.
