We all know that diseases are caused by pathogens and microorganisms. These obviously can't be seen with the naked eye. So, instruments that manage to magnify a hundred times over what is normally seen are required to view these microorganisms. This brought about the invention of one of the most important instruments in science, the microscope. There are many different types of this device which differ in their structure and function, and are made for a specific purpose. Two such types are the dissecting, and the compound microscope.
Compound Microscope vs Dissecting Microscope
A dissecting microscope has two lens arrays which are aligned in such a manner that they bring about a three dimensional magnification of the object. It usually has two eyepieces for this same reason. The compound type uses multiple lenses to collect light, and its lenses help to focus the light to the eye of the viewer. Due to the presence of these multiple lenses, these are not only large and heavier but they are also more expensive when compared the dissecting variant.
Light for Viewing
In all microscopes, the object that is magnified is viewed with the help of light. In some cases, this light may act directly to illuminate the object, or it may be reflected in nature, so that the object gets illuminated via the reflections. The light on the basis of which the object present on the glass slide is viewed is one of the differentiating points. In a dissecting or stereo microscope, the object is viewed with the help of reflected light rather than transmitted light, whereas in the compound type, the light is transmitted through the object itself. The main reason why reflected light is preferred in a dissecting microscope is that this kind of light allows a person to view an object that would either be too thick in its sectioning and/or too opaque, due to which it will not allow light to pass through.
The resolution of the dissecting microscope is much lower than that of the compound variant, and hence, the former is used to study the surface of solid substances, studying dissections, in microsurgeries, for watch making, and in the making of small circuit boards. The compound variant is used to view far more minute and smaller things, like bacteria, protozoa, cells, etc.
These magical devices have come a long way since their invention centuries ago, and now we have complex versions of these devices, like the electron microscope, which provides an even greater level of magnification. You can read more about the different types of this device here.