About the correct usage and operating procedures of bright field microscopy
1. Some students said: The magnification of a bright field microscope is equal to the eyepiece multiplied by the objective lens. The correct statement is: the magnification of a microscope is equal to the magnification of the eyepiece multiplied by the magnification of the objective lens.
2. Some students often put paper, hair, leaves, and even fingers directly under the microscope for observation. What's more, the material is placed on a reflector for observation. The correct approach is: the object to be observed must be made thin and transparent.
3. Move the aligned bright field microscope at will, so that you cannot see anything when looking at the objects in the field of view of other students' microscopes. When wiping the optical lens, you are used to wiping it back and forth repeatedly or using too much force. This will damage the optical axis of the objective lens and eyepiece, or damage the anti-reflection coating on the surface of the objective lens (eyepiece), affecting the clarity of the object image and eyepiece.
The correct operation method is: use lens cleaning paper to gently wipe in one direction, or gently wipe from the center outwards. If you just want to remove the dust on the lens, just blow it away with a hair dryer.
4. When switching objective lenses of different magnifications, use the objective lens directly by hand, which will easily cause the optical axis of the objective lens to tilt. Because the objective lens converter is an important component that requires high mechanical precision, its rotating plate is made of copper alloy, which has stable performance, but the material is soft and the threads are easily damaged by force. Frequently pulling the objective lens with force will cause the axis of the optical system to tilt, causing the parameters of the objective lens to change, thereby affecting the quality of the microscope and affecting the observation effect. The correct operation method is: hold the rotating lever of the microscope nosepiece with your hands and rotate it.
5. Tilt the microscope when observing the temporary mounting. This will cause water to flow to the stage, corroding and contaminating the stage. In addition, the materials to be observed (such as animal cells) may run away with the water flow.
6. I am not used to keeping both eyes open when observing objects. I observe with my left eye and always open one eye and close the other. If you are not used to seeing with your left eye, you draw with the help of your right eye.
7. Ignore the difference in field of view between low-magnification objective lens, high-magnification objective lens and oil lens. For a certain type of bright field microscope, the field of view is inversely proportional to the magnification, that is, the higher the magnification of the microscope, the smaller the field of view. When many students use microscopes, they often complain to their teachers: I can see very clearly under a low-power lens, but I can't find the target when I switch to a high-power lens. The reason is that I am not familiar with the principle of field of view and can only roughly find it under low magnification.
After observing the target, I rush to switch to a high-power lens. As a result, the part to be observed is not within the field of view of the high-power lens, and naturally the target cannot be found.
8. Ignore the low- and high-magnification lenses and use oil lenses to adjust the incident light. Many students have too much lighting when using low-power lenses, and weak lighting when using high-power lenses or oil lenses. The correct approach is: use a low-magnification lens to evenly illuminate the light into a bright bluish-white color. When changing to a high-magnification lens or oil lens, expand the diaphragm, or use a concave reflector and an ascending condenser to enhance the incident light. Of course, the most scientific method is to use a transformer to control artificial light sources, and it is most appropriate to adjust the intensity of incident light.
In short, the use of a bright field microscope seems simple, but it is not easy for students to actually operate it in a standardized manner and use it skillfully. Only under the scientific guidance of teachers and truly feeling and experiencing things in person can we learn something, have fun learning, and then cultivate our innovative spirit and inquiry ability.
