Laboratory work “The device of magnifying devices and the rules for working with them. Magnifier device How many times does a microscope magnify

Magnifier, microscope, telescope.

Question 2. What are they used for?

They are used to enlarge the object in question several times.

Laboratory work No. 1. The device of a magnifying glass and examining the cellular structure of plants with its help.

1. Consider a hand magnifier. What parts does it have? What is their purpose?

A hand magnifier consists of a handle and a magnifying glass, convex on both sides and inserted into a frame. When working, the magnifying glass is taken by the handle and brought closer to the object at such a distance at which the image of the object through the magnifying glass is the clearest.

2. Examine with the naked eye the pulp of a semi-ripe fruit of a tomato, watermelon, apple. What is characteristic of their structure?

The pulp of the fruit is loose and consists of the smallest grains. These are cells.

It is clearly seen that the pulp of the tomato fruit has a granular structure. In an apple, the flesh is a little juicy, and the cells are small and close to each other. The pulp of a watermelon consists of many cells filled with juice, which are located either closer or further away.

3. Examine the pieces of fruit pulp under a magnifying glass. Sketch what you see in a notebook, sign the drawings. What shape are the fruit pulp cells?

Even with the naked eye, and even better under a magnifying glass, you can see that the pulp of a ripe watermelon consists of very small grains, or grains. These are cells - the smallest "bricks" that make up the bodies of all living organisms. Also, the pulp of a tomato fruit under a magnifying glass consists of cells that look like rounded grains.

Laboratory work No. 2. The device of the microscope and methods of working with it.

1. Examine the microscope. Find the tube, eyepiece, lens, stage stand, mirror, screws. Find out what each part means. Determine how many times the microscope magnifies the image of the object.

The tube is a tube that contains the eyepieces of a microscope. Eyepiece - an element of the optical system facing the eye of the observer, part of the microscope, designed to view the image formed by the mirror. The lens is designed to build an enlarged image with fidelity in terms of the shape and color of the object of study. The tripod holds the tube with the eyepiece and objective at a certain distance from the object table, which is placed on the test material. The mirror, which is located under the object table, serves to supply a beam of light under the object under consideration, i.e., improves the illumination of the object. Microscope screws are mechanisms for adjusting the most efficient image on the eyepiece.

2. Familiarize yourself with the rules for using a microscope.

When working with a microscope, the following rules must be observed:

1. Work with a microscope should be sitting;

2. Inspect the microscope, wipe the lenses, eyepiece, mirror from dust with a soft cloth;

3. Set the microscope in front of you, a little to the left, 2-3 cm from the edge of the table. Do not move it during operation;

4. Fully open the diaphragm;

5. Always start working with a microscope at a low magnification;

6. Lower the lens to the working position, i.e. at a distance of 1 cm from the glass slide;

7. Set the illumination in the field of view of the microscope using a mirror. Looking into the eyepiece with one eye and using a mirror with a concave side, direct the light from the window into the lens, and then maximally and evenly illuminate the field of view;

8. Put the micropreparation on the stage so that the object under study is under the lens. Looking from the side, lower the lens with a macro screw until the distance between the lower lens of the objective and the micropreparation is 4-5 mm;

9. Look into the eyepiece with one eye and turn the coarse adjustment screw towards yourself, smoothly raising the lens to a position at which the image of the object will be clearly visible. You can not look into the eyepiece and lower the lens. The front lens can crush the coverslip and scratch it;

10. Moving the preparation with your hand, find the right place, place it in the center of the microscope field of view;

11. Upon completion of work with a high magnification, set a low magnification, raise the lens, remove the preparation from the working table, wipe all parts of the microscope with a clean cloth, cover it with a plastic bag and put it in a cabinet.

3. Work out the sequence of actions when working with a microscope.

1. Place the microscope with a tripod towards you at a distance of 5-10 cm from the edge of the table. Aim the light with a mirror into the opening of the stage.

2. Place the prepared preparation on the stage and secure the slide with clips.

3. Using the screw, slowly lower the tube so that the lower edge of the lens is 1-2 mm from the preparation.

4. Look into the eyepiece with one eye, without closing or closing the other. While looking into the eyepiece, use the screws to slowly raise the tube until a clear image of the object appears.

5. Put the microscope back in its case after use.

Question 1. What magnifying devices do you know?

Hand magnifier and tripod magnifier, microscope.

Question 2. What is a loupe and what magnification does it give?

A magnifying glass is the simplest magnifying device. A hand magnifier consists of a handle and a magnifying glass, convex on both sides and inserted into a frame. It magnifies objects by 2-20 times.

A tripod magnifier magnifies objects 10-25 times. Two magnifying glasses are inserted into its frame, mounted on a stand - a tripod. An object table with a hole and a mirror is attached to the tripod.

Question 3. How does a microscope work?

Magnifying glasses (lenses) are inserted into the telescope, or tube, of this light microscope. At the top end of the tube is an eyepiece through which various objects are viewed. It consists of a frame and two magnifying glasses. At the lower end of the tube is placed a lens consisting of a frame and several magnifying glasses. The tube is attached to a tripod. An object table is also attached to the tripod, in the center of which there is a hole and a mirror under it. Using a light microscope, one can see an image of an object illuminated with the help of this mirror.

Question 4. How to find out what magnification the microscope gives?

To find out how much the image is magnified when using a microscope, multiply the number on the eyepiece by the number on the objective lens being used. For example, if the eyepiece is 10x and the objective is 20x, then the total magnification is 10 x 20 = 200x.

Think

Why is it impossible to study opaque objects with a light microscope?

The main principle of operation of a light microscope is that light rays pass through a transparent or translucent object (object of study) placed on the object table and enter the lens system of the objective and eyepiece. And light does not pass through opaque objects, respectively, we will not see the image.

Tasks

Learn the rules for working with a microscope (see above).

Using additional sources of information, find out what details of the structure of living organisms allow you to see the most modern microscopes.

The light microscope made it possible to examine the structure of cells and tissues of living organisms. And now, it has already been replaced by modern electron microscopes, which allow us to examine molecules and electrons. A scanning electron microscope allows you to obtain images with a resolution measured in nanometers (10-9). It is possible to obtain data concerning the structure of the molecular and electronic composition of the surface layer of the surface under study.

If we break a pink, unripe fruit of a tomato (tomato), watermelon or apple with loose pulp, we will see that the pulp of the fruit consists of tiny grains. These are cells. They will be better seen if you examine them with magnifying instruments - a magnifying glass or a microscope.

magnifier device. A magnifying glass is the simplest magnifying device. Its main part is a magnifying glass, convex on both sides and inserted into a frame. Magnifiers are manual and tripod (Fig. 16).

Rice. 16. Manual magnifier (1) and tripod (2)

A hand magnifier magnifies objects 2-20 times. When working, it is taken by the handle and brought closer to the object at such a distance at which the image of the object is most clear.

The device of a magnifying glass and examining with its help the cellular structure of plants

Consider a hand magnifier. What parts does it have? What is their purpose?
Examine with the naked eye the pulp of a semi-ripe fruit of a tomato, watermelon, apple. What is characteristic of their structure?
Examine the pieces of fruit pulp under a magnifying glass. Sketch what you see in a notebook, sign the drawings. What shape are the fruit pulp cells?

Light microscope device. With a magnifying glass, you can see the shape of the cells. To study their structure, they use a microscope (from the Greek words "micros" - small and "scopeo" - I look).

The light microscope (Fig. 17) that you work with at school can magnify the image of objects up to 3600 times. Magnifying glasses (lenses) are inserted into the telescope, or tube, of this microscope. At the upper end of the tube is an eyepiece (from the Latin word "oculus" - eye), through which various objects are viewed. It consists of a frame and two magnifying glasses. At the lower end of the tube is placed a lens (from the Latin word "objectum" - an object), consisting of a frame and several magnifying glasses.

The tube is attached to a tripod. An object table is also attached to the tripod, in the center of which there is a hole and a mirror under it. Using a light microscope, one can see an image of an object illuminated with this mirror.

Rice. 17. Light microscope

To find out how much the image is enlarged when using a microscope, you need to multiply the number indicated on the eyepiece by the number indicated on the object used. For example, if the eyepiece is 10x and the objective is 20x, then the total magnification is 10 x 20 = 200x.

How to work with a microscope

Place the microscope with a tripod towards you at a distance of 5-10 cm from the edge of the table. Aim the light with a mirror into the opening of the stage.
Place the prepared preparation on the stage and fix the glass slide with clamps.
Using the screw, smoothly lower the tube so that the lower edge of the objective is 1-2 mm from the specimen.
Look into the eyepiece with one eye, without closing or closing the other. While looking into the eyepiece, use the screws to slowly raise the tube until a clear image of the object appears.
Put the microscope back in its case after use.

A microscope is a fragile and expensive device: you need to work with it carefully, strictly following the rules.

The device of the microscope and methods of working with it

Familiarize yourself with the rules for using a microscope.
Work out the sequence of actions when working with a microscope.

New concepts

Cell. Magnifier. Microscope: tube, eyepiece, lens, tripod

Questions

What magnifying devices do you know?
What is a loupe and how much magnification does it give?
How is a microscope made?
How do you know what magnification a microscope gives?

Think

Why is it impossible to study opaque objects with a light microscope?

Tasks

Learn the rules for working with a microscope.

Using additional sources of information, find out what details of the structure of living organisms allow you to see the most modern microscopes.

Do you know that...

Light microscopes with two lenses were invented in the 16th century. In the 17th century Dutchman Anthony van Leeuwenhoek designed a more advanced microscope, giving an increase of up to 270 times, and in the 20th century. The electron microscope was invented, magnifying the image by tens and hundreds of thousands of times.

1. Answer the question.

Why do I use magnifiers?

Answer: To study small objects.

hand magnifier

2. Consider a hand magnifier. Write the names of its parts and the functions they perform.

3. Take pieces of tomato pulp (watermelon, apple). Examine them with the naked eye. What will you come up with?

Answer: Soft thin peel and seeds.

4. Examine the pieces with a magnifying glass. What do you see?

Answer: Pulp cells.

5. Conclusion

Answer: Loupe so much that you can see cells that are not visible to the naked eye.

light microscope

1) Examine the microscope. Find the main parts of the microscope. Use the text in the textbook and the picture to find out what their meaning is.

2) Familiarize yourself with the rules for working with a microscope. Learn to set the light, achieve good illumination of the field of view.

3) Check each other's knowledge of the rules for using a microscope.

4) Determine how many times the microscope magnifies the image of the object. (In 300 times. Depends on the microscope)

5) Work out the sequence of actions when working with a microscope.

Denisenko T.E.

Light microscope device.

The light microscope is most often used in biological, medical, veterinary and laboratory practice.

Some characteristics of the microscope: aperture, resolution,

the field of view depends on the diameter of the diaphragms and frames of the lens systems that limit the light fluxes entering the microscope optics. The microscope is an optical system consisting of 2 stages of magnification: 1 - main, provided by the objective; 2 - eyepiece. The lens forms a real, enlarged and inverted image of the object in question. The resulting intermediate image is viewed through an eyepiece, which, like a magnifying glass, further magnifies it. The final magnified image seen through the eyepiece is virtual and direct, located at the best viewing distance from the observer's eye (250mm). As a result, an image inverted relative to the preparation is seen in the microscope. To find out the total magnification of the microscope, you need to look at how many times the lens and eyepiece used increase. The product of these values is the total magnification of the microscope.

The path of rays in a light microscope.

In the microscope, distinguishmechanical andoptical parts. The mechanical part is represented by a tripod (consisting of a base and a tube holder) and a tube mounted on it with a revolver for mounting and changing lenses. The mechanical part also includes: an object table for the preparation, devices for fastening the condenser and light filters, mechanisms built into the tripod for coarse (macromechanism, macroscrew) and fine (micromechanism, microscrew) movement of the object table or tube holder.

The optical part is presentedlenses , eyepieces andlighting system , which in turn consists of located under the subject tableAbbe condenser and a built-in illuminator with a low-voltage incandescent lamp and a transformer. Lenses screw intorevolver , and the corresponding eyepiece through which the image is observed is installed on the opposite side of the tube.

microscope device.

Mechanical

Optical part

2. Monocular attachment

1. Eyepiece

3.Revolver

4. Lens

5. Subject table

9. Foundation

6.7. Condenser

10.Tripod

8.Illuminator with lens

11, 12, 13. - drug holder

14. Macro screw

15. Micro screw

16, 17. Preparation agent

18. Switch

19. Light intensity adjustment

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