Today, microscopes are of great importance especially on the field of Biological Science. One of its major use is to determine the sizes of microorganisms which are of great importance in understanding certain biological phenomena. Getting the actual size of microscopic objects such as microorganisms using calibrated eyepiece micrometer is termed micrometer (Echoic, et. Al. , 2000). It is important for investigators across a number of disciplines. A biologist, for example, needs to know the exact size of two organisms to provide an intelligent comparison .
The intent of this activity is to create an awareness in proper handling techniques ND correct use of a microscope to students pursuing courses in the field of Biological Sciences. This activity is also intended to teach students microscope calibration techniques. To able to obtain the exact measurement of a specimen, the ocular micrometer should be calibrated first. By doing so, the calibration constant (C) is obtained. To get the calibration constant, a stage micrometer, an ocular micrometer and a microscope is used.
The ocular micrometer was placed inside the ocular lens of the microscope and the stage micrometer on the stage. The field was adjusted so that a line in the ocular micrometer is superimposing a line in the stage micrometer. Once this was set, the number of divisions in both micrometers from the first superimposing lines to the next line that superimposed was counted. The number of divisions in the stage micrometer was divided by the divisions in the ocular micrometer. The quotient was multiplied by pm.
The product obtained was the calibration constant. The calibration constant was determined in each of the objective lenses of the microscope. Once the ocular micrometer was calibrated, the pessimism were viewed and measured. The correct measurement was obtained by counting the ocular micrometer divisions occupied by the specimen and multiplying it by the calibration constant of the objective lens used. The deviation between the measurement should only appear on the decimal places of the figure.