Biological Microscope Eyepiece Microscope Microscope Micrometer Formula
When using a biological microscope, it is sometimes necessary to measure the length of the observed object. Due to the extremely small size of the observed object, it is not possible to measure it directly using conventional measuring tools. Therefore, we need to use a micrometer specifically designed for microscopes. To measure the length of the object being tested, two tools are required, one of which is mounted in the eyepiece and is called the eyepiece micrometer; A special cover glass is placed on the stage, with a small circular area in the middle engraved with small scales. The total length is usually 1mm, with a total of 100 small grids, which means the distance between each grid is 10um. Its function is to determine the length represented by each grid of the eyepiece micrometer under biological microscope observation.
When using, we need to first install the eyepiece micrometer into the eyepiece tube. The specific operation is as follows: first, remove the eyepiece from the microscope, and there is a gear shaped circular structure at the end away from the lens (which is where we usually observe). Unscrew it, and then install the eyepiece micrometer into it, paying attention to placing the front side on the field stop. Then, screw it back and put the eyepiece back in place. Some microscopes, due to their precise structure, do not allow disassembly and require specialized eyepieces with micrometer scales. Then place the micrometer ruler on the stage and adjust the focus of the microscope until the clear scale on the ruler can be seen. At this point, adjust one end of the two rulers to coincide with the entire scale, and then find where the other end overlaps. Count the number of squares in their overlapping area to calculate the actual magnification of the eyepiece micrometer under magnification.
The specific calculation formula is as follows:
Each grid of the eyepiece micrometer=(number of overlapping scales X10) ÷ number of overlapping grids of the sight scale. The overlapping grid of the ruler in the above figure is 4 grids, and the overlapping grid of the eyepiece micrometer is 10 grids. From this, the length represented by each grid of the eyepiece micrometer can be calculated as (4X10)/10=4um.
After determining the length represented by each grid of the eyepiece micrometer, move the ruler away and use it to determine the actual length of the object being tested. Due to the multiple objectives of a biological microscope, each with a different magnification, the actual length represented by the eyepiece micrometer varies at different magnifications. Therefore, recalibration should be performed when switching magnifications.
