The microscope is the most useful and necessary tool for scientists in the laboratory. In our experiments, our aim was to use and understand the functions of a microscope properly. There are some concepts to understand the microscope.
First one is resolution. In a simple definition, resolution is a concept which allows us to differentiate two objects. For example, when two objects are very close to each other we cannot differentiate them with the naked eye, but microscope has a bigger resolution than a naked eye so that the microscope allows us to differentiate two different objects.
The second one is limit of resolution. It is the shortest distance between two objects that a microscope can show. If the distance between two objects is smaller than the limit of resolution, it cannot be separated with a microscope and it would be look like a whole object rather than different objects. Limit of resolution can be found by this formula: l.r = 0,61 ?/ N.A. (Abbe equation), thus limit of resolution does not depend on the characteristics of an objective lens, it depends on the light source.
The third concept is magnification. It is about how many times can a microscope enlarge an object. Microscope enlarges the object two times first with oculars, second with objectives. Total magnification can be found by multiplying the eyepiece’s magnification(10x) and the objective’s magnification (4x, 10x, 40x and 100x). 40x and 100x are the major objectives on a microscope. There are some differences between 4x and 100x usage. While using 100x there should be an immersion oil between the specimen and the object; with oil, numerical aperture of the 100x objective can be increased therefore limit of resolution would decrease for 100x.
The fourth concept is contrast. It helps us to see the object clearly by adjusting the light or the color of the specimen. In such cases, adjusting contrast might be a necessary thing to do to see the object. Otherwise, object might be look too lightened or too dark to see. To change the color of the specimen, staining techniques are used. Stained specimen has increased contrast rather than the unstained one and there might be some interactions between molecules and the dye which allows us to see the organelles, nucleus or etc. more clearly. There are some solutions to stain the specimen. Methylene blue, Lugol’s Iodine, neutral red and Janus Green B are some of the staining solutions. All these solutions are used in different kind of cells and they interact with different cell parts.