Put the magnifying glass in front of the object at an appropriate distance, and watch the magnified image from the lens. Pay attention to the fact that the object is not actually magnified.
2. Pay attention to fire protection-secondary function
Under strong light, the focal part of the lens will be particularly bright, and the focal part will zoom or catch fire.
3. It can also be used for jewelry identification detection, substrate surface quality and color correction, etc.
Extended data:
I. Principles
In order to see the tiny object or the details of the object clearly, it is necessary to move the object closer to the eye, which can increase the viewing angle and form a larger real image on the retina. But when the object is too close to the eye, it is not clear.
In other words, to be good at observation, we should not only make the object have a large enough opening angle to the eyes, but also take a suitable distance. Obviously, for the eyes, these two requirements are mutually restrictive. If you put a convex lens in front of your eyes, this problem can be solved.
The convex lens is the simplest magnifying glass and a simple optical instrument to help the eyes observe tiny objects or details.
Second, the method of use
Observation method 1: make the magnifying glass close to the observed object, the observed object will not move, and the distance between the human eye and the observed object will not change, then move the hand-held magnifying glass to move back and forth between the object and the human eye until the image becomes larger and clearer.
Observation method 2: the magnifying glass is as close to the eyes as possible. Keep the magnifying glass still and move the object until the image becomes bigger and clearer.
References:
Baidu encyclopedia-magnifying glass