As you know, practice is the criterion of truth and the best way to know the world around. At the same time, there is something that we see with the naked eye, that is, ordinary surrounding objects, as well as a microcosm that can be seen using a special device – a microscope.

biological microscope

When is it worth starting the knowledge of this world? I think the sooner the better. The microscope is quite easy to use and does not require reading multi-page manuals. With ready-made drugswith it you can observe many interesting objects of different shapes from flowers, from different parts of the living world.

Choosing a microscope is best to start by studying what main parts it consists of. We will not consider electron microscopes, which are needed more for a scientist than for a schoolboy.

Parts of a biological microscope

  1. The eyepiece is the optical part of the microscope that allows you to observe the image from the objective. It is to him that the eye is brought for observation.
  2. Eyepiece tube – an eyepiece is inserted into it, and light from the lens passes through it. Without the eyepiece tube, the image would be overexposed.
  3. Objectives – the optical part of the microscope, facing the preparation. It is the lens that forms an enlarged image of small details. As a rule, a microscope has several objectives that rotate in a revolving device, thereby allowing you to change the magnification of the microscope.

  4. Turret and lenses

    The magnification of a microscope is actually obtained by multiplying the magnification of the eyepiece and the objective.

  5. Focus knob – This moves the top of the microscope with the above elements closer and further away from the stage, which can be used to achieve a sharp image. In simpler models, the stage itself moves.

  6. Two-way focus control

  7. Subject table – as the name implies, this is a table with a hole on which you can put a glass slide with the preparation. Glass, at the same time, is pressed against it with special clamps.
  8. Illumination, mirror – serve to create a light flux that shines through the drug, and then enters the lens.

  9. Downlight LED Lamp

  10. base of the microscope.
  11. Diaphragm disk – allows you to change the diameter of the hole through which the light from the backlight passes.

  12. Lower LED Illumination Aperture Selection Wheel

We have considered the device of a microscope intended for the study of micropreparations. In addition to such devices, there are microscopes for observing larger objects in reflected light, they are also called instrumental. Typically, these microscopes are binocular, that is, they have two eyepieces. They can be suitable for studying minerals or whole insects.

So, first of all, when choosing a microscope, one should decide on the type of observed objects. In general, in fact, the first type of microscopes – biological (parts of which we considered) turns out to be much more in demand, for a number of reasons:

  1. Microscopes with high magnification allow you to observe what is completely invisible to the naked eye.
  2. The school curriculum includes the use of this type of microscope.
  3. Larger range and prevalence.

Next, we will consider on what grounds it is worth choosing a microscope.

Manufacturing materials

“Conventional” optical microscopes are a device whose fundamental design has not changed for many years. If you want a microscope that is durable and gives a high-quality image, it is not worth saving. The manufacturer, in particular, usually indicates the material for the manufacture of microscope lenses – ideally, this should be a special optical glass. The material of a microscope body is often difficult to determine, but the material of a lens body is easier to determine. If we see that the lenses are made of metal, this already says a lot about the quality of the device as a whole. We strongly advise you to consider models from such “eternal” materials as metal and glass.


When choosing a microscope, beginners are often chasing maximum magnification. After all, it seems that the more the better, right? Yes, this is true, but you need to understand that with increasing magnification, the visible area of ​​​​the image decreases. Thus, less light enters the lens and the picture becomes darker. Therefore, it may turn out that it will simply be impossible to use an inexpensive microscope with high magnification.

For example, here is an image of a classic preparation of onion skin, made at different magnifications:

Onion epidermis (40x)

Onion epidermis (100x)

Onion epidermis (400x)

As you can see, in this case, the information content practically does not increase with increasing magnification. This is the case with most drugs.

But here’s an example in reverse:

Euglena (400x)

In this case, the organism in question is so small that it is most interesting to observe it at high magnification.

Has a built-in backlight

Microscopes can use two types of illumination:

  1. A pivoting mirror that reflects an external light source.
  2. Built-in LED lighting. It can be the only option for illuminating the preparation, or it can be used in addition to a mirror.

Illumination can be top or bottom. The first, as you can understand, serves to work with transparent preparations, and the second – with opaque ones.

The built-in backlight can work both from batteries of one type or another, and from the mains.

Power adapter for microscope illumination

Batteries used to power the microscope illumination

Ability to fine-tune focus

There is a rule that the higher the magnification of the microscope currently used, the more difficult it is to “get into focus” on it. That is, higher focusing accuracy is required. Therefore, on microscopes, there may be a so-called fine focusing, in which the lens moves much more slowly than usual. In such cases, the microscope has two knobs – one for coarse focusing, the other for fine focusing.

If there are two types of focusing, you should work with the drug in the following sequence:

  1. Put the preparation on the stage, adjust the lighting.
  2. Using coarse adjustment, bring the lens closer to the preparation without touching it (the position of the lens is controlled by the naked eye, from the side).
  3. While observing through the eyepiece, move the lens away from the preparation until a focused image flashes.
  4. With the help of fine adjustment, observing through the eyepiece, make the final focus.

Connecting a digital camera

We live in the 21st century, and progress has led to the fact that we can use digital technologies to display an image on a computer, and then write it as a file. For this, a camera can be used, which is inserted instead of an eyepiece and connected to a computer via a USB connector. Further, using a special program, you can view this picture on a monitor or laptop screen.

Microscope digital camera

There are also purely digital microscopes, in which the camera and lens are combined into a single body. Here the image can only be seen on the computer screen.

Digital microscope

At the same time, it should be noted that for a “real” study of the drug, it would be better to try to draw it yourself on plain paper, focusing on a live picture. Firstly, the live image will be of much higher quality, and secondly, the necessary details will be remembered in the process of transferring the image.

So, if you are wondering what to give a child, then a microscope would be a great option. Also, it may well be that you yourself dreamed of acquiring it as a child, but something did not grow together. Although from the outside it may seem that this desire is not serious, the microscope will be of interest to an adult, a teenager. Given that now such equipment is on sale, armed with the knowledge gleaned from our article, it will not be so difficult to make a choice.


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