What are the parts of a hand magnifier called? The device of magnifying devices

Exercise 1.

1. Consider hand and tripod magnifiers. Find the main parts, find out their purpose.

Answer. The manual consists of a frame in which the lens is set and a handle for holding the magnifier. The lens is used to view the object at a magnification of 2-5 times. tripod magnifier so called because all its parts are fixed on a tripod, namely: the eyepiece and lenses ( magnifying glasses, allowing you to examine the object at a magnification of 2-25 times), an object table on which the object is located for examination, a mirror that allows you to direct light on the object, screws to obtain a clear image.

3. Examine the pieces of tomato pulp, watermelon under a magnifying glass. Make a drawing. What is the structure of the pulp?

The pulp of a tomato consists of balls - cells.

The pulp of a watermelon consists of "seeds" - cells.

Task 2.

1. Examine the microscope. Find the main parts. Find out their purpose. Familiarize yourself with the rules of working with a microscope.

Answer. The basis of the whole structure is a tripod. It is a curved element to which all other parts of the device are attached. Its wide base is what supports the whole microscope and thanks to which it is stably fixed in a standing position. A mirror that is attached to a tripod from the bottom of the device. It is necessary to capture sunlight and beam direction to the stage. It is fixed on both sides on movable hinges, which facilitates the process of setting the light. The subject table is a structure fixed on a tripod, most often of a round or rectangular shape, equipped with metal fasteners. It is on it that the micropreparation under study is installed, which is clearly fixed on both sides and remains immobile. A telescope that ends with an eyepiece on one side and lenses of different magnifications on the other. Also securely attached to the tripod. Objectives are located immediately above the stage and serve to focus and magnify the image. Most often there are three of them, each can be moved and fixed depending on the need. The eyepiece is the top of the telescope, and it is designed to directly observe the object. The last important part that all magnifying devices of this kind have is macro and micro screws. They serve to adjust the movement of the telescope in order to adjust the best quality Images.

Microscope rules.

1. Keep the microscope in its case.

2. To carry the microscope, taken out of the case, with two hands: hold the tripod with one, support the microscope from below, with the stand, with the other.

3. When adjusting the telescope, make sure that the objective lenses do not touch the slide.

4. Do not touch the magnifying glasses of the eyepiece and the objective with your hands.

5. Do not remove the eyepiece from the telescope unnecessarily.

6. Viewing a micropreparation should begin with a small magnification of the objective. Use high magnification only when necessary.

7. Upon completion of work, remove the micropreparation from the stage, wipe the stage with a clean cloth, put the tube and the mirror in the non-working position. If necessary, put the microscope back in its case.

The magnifying glass and the microscope are the main magnifying instruments that are used for scientific research. They allow you to look inside the cells of living organisms and find out their structure.

magnifier device

The simplest magnifying device - magnifying glass. Its main part is a convex magnifying glass - a lens inserted into the frame. Loupes give magnification from 2.5 to 10 and even up to 25 times. Some of them have a handle (manual magnifier), others are fixed in a special tripod (tripod magnifier). A hand magnifier can be used not only in the laboratory, but also during observations in nature. A tripod magnifier has a table and a mirror fixed under it. The object in question is placed on a table and illuminated with a mirror.

Light microscope device

Microscope- a complex device that gives an increase of tens, hundreds and even thousands of times. The school usually uses a light microscope. It consists of a spotting scope, a tripod with a table and a mirror. The telescope has magnifying glasses: the lower ones are assembled in the lens, the upper ones are in the eyepiece (lat. oKulUS - eye). To find out the magnification of the microscope, you need to multiply the numbers indicated near the lenses of the objective and the eyepiece (for example, 20 × 7 = 140 means that the microscope magnifies 140 times). To examine the object under a microscope, a micropreparation is prepared. The micropreparation is placed on the object table. Light rays are directed into the opening of the table and the telescope using a mirror. Thanks to this, the preparation is illuminated and its details are clearly visible. Microscope tripod screws are designed for mechanical approach or removal of the telescope with lenses to the object table. This allows you to set a distance to the eyes at which the preparation is clearly visible.

Stages of working with a microscope

1. Put the microscope with the handle of the tripod and the eyepiece towards you, and the mirror towards the light source. Set the mirror so that the illuminated circle is clearly visible in the field of view (look into the eyepiece with one eye, without closing the other).
2. Prepare a micropreparation.
3. Place the preparation over the hole in the stage and fix it with clamps.
4. When lowering the telescope with a screw, make sure that the lower magnifying glass does not touch the preparation (at low magnification, the distance between the magnifying glass and the object should be about 1 cm).
5. Adjust the sharpness of the image with the adjustment screws.
6. Moving the glass slide on the table, find the place where the cells are most clearly visible.

Rules for working with a microscope

1. Carry the microscope with both hands. With one hand, hold the device by the tripod, with the other - support the stand from below.
2. Make sure that the objective lens does not touch the preparation during adjustment.
3. Do not touch the magnifying glasses with your hands, do not remove them from the telescope.
4. After completing the work, wipe the table with a clean cloth, put the microscope back in its case.

1) Lens 2) A tripod magnifier has a device for rigid installation or mounting it on any flat surface. This device is a tripod. A hand magnifier has only a handle. 3) The device of light microscopes: 1 - eyepiece, 2 - tube, 3 - tube holder, 4 - coarse screw, 5 - micrometer screw, 6 - stand, 7 - mirror, 8 - condenser, iris diaphragm and light filter, 9 - object table , 10 - revolving device, 11 - lens, 12 - housing of the collector lens, 13 - cartridge with a lamp, 14 - power supply. The objective lens is one of the most important parts of a microscope as it determines the useful magnification of an object. The lens consists of a metal cylinder with lenses built into it, the number of which can be different. The magnification of the lens is indicated by numbers on it. For training purposes, x8 and x40 lenses are usually used. The quality of a lens determines its resolution. The eyepiece is much simpler than the lens. It consists of 2-3 lenses mounted in a metal cylinder. Between the lenses is a constant aperture that defines the boundaries of the field of view. The lower lens focuses the image of the object built by the lens in the plane of the diaphragm, while the upper one serves directly for observation. The magnification of the eyepieces is indicated on them by numbers: x7, x10, x15. Eyepieces do not reveal new details of the structure, and in this respect their magnification is useless. Thus, the eyepiece, like a magnifying glass, gives a direct, imaginary, enlarged image of the observed object, constructed by the lens. To determine the overall magnification of the microscope, multiply the magnification of the objective by the magnification of the eyepiece. The lighting device consists of a mirror or an electric illuminator, a condenser with an iris diaphragm and a light filter located under the object stage. They are designed to illuminate an object with a beam of light. The mirror serves to direct light through the condenser and the stage opening onto the object. It has two surfaces: flat and concave. In laboratories with scattered light, a concave mirror is used. The electric illuminator is installed under the condenser in the socket of the stand. The condenser consists of 2-3 lenses inserted into a metal cylinder. When it is raised or lowered with a special screw, the light falling from the mirror onto the object is condensed or scattered accordingly. The iris diaphragm is located between the mirror and the condenser. It serves to change the diameter of the light flux directed by the mirror through the condenser to the object, in accordance with the diameter of the front lens of the objective and consists of thin metal plates. With the help of a lever, they can either be connected, completely closing the lower lens of the condenser, or parted, increasing the flow of light. A ring with frosted glass or a light filter reduces the illumination of the object. It is located under the diaphragm and moves in a horizontal plane. mechanical system The microscope consists of a stand, a box with a micrometer mechanism and a micrometer screw, a tube, a tube holder, a coarse aiming screw, a condenser bracket, a condenser displacement screw, a revolver, and an object stage. The stand is the base of the microscope. A box with a micrometer mechanism, built on the principle of interacting gears, is fixedly attached to the stand. The micrometer screw is used to slightly move the tube holder, and, consequently, the lens at distances measured in micrometers. A full turn of the micrometer screw moves the tube holder by 100 µm, and a turn by one division lowers or raises the tube holder by 2 µm. To avoid damage to the micrometer mechanism, it is allowed to turn the micrometer screw in one direction by no more than half a turn. Tube or tube - a cylinder into which eyepieces are inserted from above. The tube is movably connected to the head of the tube holder, it is fixed with a locking screw in a certain position. By loosening the locking screw, the tube can be removed. The revolver is designed to quickly change lenses that are screwed into its sockets. The centered position of the lens is provided by a latch located inside the revolver. The tube holder carries the tube and revolver. The coarse screw is used to significantly move the tube holder, and, consequently, the lens in order to focus the object at low magnification. The object table is designed to place the drug on it. In the middle of the table there is a round hole into which the front lens of the condenser enters. On the table there are two springy terminals - clamps that secure the drug. The condenser bracket is movably attached to the micrometer mechanism box. It can be raised or lowered by means of a screw that rotates a gear wheel, which is included in the grooves of the comb-cut rack. 4) 1. Place the microscope with a tripod towards you against your left shoulder at a distance of 5-8 cm from the edge of the table. 2. lower the telescope down 1-2 mm from the stage. 3. Rotate (gently) until you get a comfortable and clear image (not streaky or hazy).