If you break up the pink, unworthy, the fruit of tomato (tomato), watermelon or apple with a loose flesh, then we will see that the pulp of fruit consists of the smallest grains. These are cells. They will be better visible if we consider them with the help of magnifying devices - a magnifying glass or microscope.
Magnifier device. Mupa is the easiest magnifying device. The main part of it is a magnifying glass, convex on both sides and inserted in rim. Magnifiers are hand and page (Fig. 16).
Fig. 16. Magnifier manual (1) and tripod (2)
Manual magnifier increases items 2-20 times. When working, it takes over the handle and approach the subject on such a distance at which the image of the subject is most clearly.
The tripod magnifier increases the items of 10-25 times. In its frames are inserted two magnifying glass, strengthened on the stand - a tripod. The subject table with a hole and mirror is attached to the tripod.
Magnifying device and examination with its help of plants
- Consider a manual magnifying glass. What parts does it have? What is their purpose?
- Consider the nearseum eye the pulp of the hallowe fruit of tomato, watermelon, apple. What is characteristic of their structure?
- Consider pieces of pulp pulp under the magnifying glass. Draw seen in the notebook, drawings sign. What form do the cells of the pulp of fruits have?
Device of light microscope. With the help of a magnifying glass, you can consider the shape of the cells. To study their structure, a microscope is used (from the Greek words "Micros" - small and "scope" - watching).
The light microscope (Fig. 17), with which you work at school, can increase the image of items up to 3600 times. In the auditorium, or a tube, this microscope is inserted by magnifying glasses (lenses). In the upper end of the tube there is an eyepiece (from the Latin word "oculus" - eye), through which various objects consider. It consists of a rim and two magnifying braids. The lens is placed at the lower end of the tube (from the Latin word "objects" - the subject) consisting of a rim and several magnifying braids.
The tube is attached to the tripod. The subject table is attached to the tripod, in the center of which there is a hole and a mirror under it. Using a light microscope, you can see an image of an object illuminated with this mirror.
Fig. 17. Light microscope
To find out how much the image is used when using a microscope, you must multiply the number specified on the eyepiece, by the number specified on the object used. For example, if the eyepiece gives a 10-fold increase, and the lens is 20x, then the overall increase of 10 x 20 \u003d 200 times.
Operation with a microscope
- Put a microscope to a tripod to myself at a distance of 5-10 cm from the edge of the table. In the opening of the subject table, send the light with a mirror.
- Place the prepared drug on the subject table and secure the subject glass by the clamps.
- Using the screw, smoothly lower the tube so that the lower edge of the lens is at a distance of 1-2 mm from the drug.
- Look at the eyepiece with one eye without closing and without clouding another. Looking into the eyepiece, with the help of the screws, slowly raise the tube until a clear image of the subject appears.
- After the operation, the microscope is removed into the case.
The microscope is a fragile and expensive device: it is necessary to work with it neatly, strictly following the rules.
Microscope device and techniques for working with it
- Examine a microscope. Find a tube, eyepiece, lens, tripod with a subject table, mirror, screws. Find out what value each part has. Determine how many times the microscope increases the image of the object.
- Get acquainted with the rules for using the microscope.
- Work out the sequence of actions when working with a microscope.
New concepts
Cell. Lupa. Microscope: Tubus, eyepiece, lens, tripod
Questions
- What magnifying devices do you know?
- What is a magnifying glass and what increase does it give?
- How is the microscope?
- How to find out what an increase in the microscope?
Think
Why with the help of a light microscope can not be examined by opaque objects?
Tasks
Learn the rules for working with a microscope.
Using additional sources of information, find out which details of the structure of living organisms allow you to consider the most modern microscopes.
Do you know that...
Light microscopes with two lenses were invented in the XVI century. In the XVII century Hollandets Antoni Van Levenguk constructed a more perfect microscope, which gives an increase of up to 270 times, and in the XX century. An electron microscope was invented, an increase in the image in tens and hundreds of thousands of times.
Magnifier, microscope, telescope.
Question 2. What are they used for?
They are used to increase the subject matter in question several times.
Laboratory work number 1. Magnifier device and examination with its help of the cellular structure of plants.
1. Consider the manual magnifying glass. What parts does it have? What is their purpose?
The manual magnifier consists of a handle and magnifying glass, convex from two sides and inserted in the frame. When working, the magnifying glass takes the handle and approach the subject at such a distance in which the image of the subject through the magnifying glass is the most clear.
2. Consider the pulp of the chopped fetus of tomato, watermelon, apple. What is characteristic of their structure?
The flesh of fruits loose and consists of the smallest grains. These are cells.
It is clearly seen that the pulp of the fruit of the tomato has a grainy structure. The apple has a little juicy pulp, and the cells are small and tightly to each other. The plow of the watermelon consists of a set filled with the juice of cells, which are located closer, then.
3. Consider pieces of pulp pulp under the magnifying glass. Draw seen in the notebook, drawings sign. What form do the cells of the pulp of fruits have?
Even with a naked eye, and even better under a magnifying glass, you can see that the pulp of mature watermelon consists of very small grains, or grains. These cells are the smallest "bricks", of which there are body of all living organisms. Also, the pulp of the fruit of tomato under the magnifying glass consists of cells similar to rounded grains.
Laboratory work number 2. Microscope device and working with it.
1. Examine the microscope. Find a tube, eyepiece, lens, tripod with a subject table, mirror, screws. Find out what value each part has. Determine how many times the microscope increases the image of the object.
Tubus - a tube in which the eyepieces of the microscope are concluded. Okular is an element of an optical system facing an observer eye, part of a microscope intended for viewing an image generated by a mirror. The lens is designed to build an enlarged image with the accuracy of the form and color of the study object. The tripod holds a tube with an eyepiece and lens at a certain distance from the subject table, which houses the material under study. The mirror that is located under the subject table serves to supply the beam of light under the subject matter under review, i.e. improves the illumination of the subject. Microscope screws are mechanisms to configure the most efficient image on the eyepiece.
2. Get acquainted with the rules for using the microscope.
When working with a microscope, the following rules must be followed:
1. Working with the microscope follows;
2. Microscope view, wipe from dust with a soft napkin lenses, eyepiece, mirror;
3. Install the microscope in front of it, a little left of 2-3 cm from the edge of the table. During work, it does not shift;
4. Open completely diaphragm;
5. Working with a microscope is always started with a small increase;
6. Lower the lens in the working position, i.e. at a distance of 1 cm from the slide glass;
7. Install the lighting in the field of view of the microscope using the mirror. Looking at one eye into the eyepiece and using a mirror with a concave side, to send light from the window into the lens, and then maximize and evenly illuminate the field of view;
8. Put the microsperature on the subject table so that the object being studied is under the lens. Looking on the side, lower the lens using macroventa until the distance between the lower lens and the micro-process is 4-5 mm;
9. Watch with one eye into the eyepiece and rotate the screw of the coarse tip on itself, smoothly raising the lens to the position, in which the image of the object will be clear. You can not look into the eyepiece and lower the lens. Frontal lens can crush the coating glass, and scratches will appear on it;
10. Moving the drug with hand, find the right place, arrange it in the center of the microscope view;
11. At the end of work with a large magnification, set a small increase, lift the lens, remove the drug from the working table, wipe with a clean napkin all parts of the microscope, cover it with a plastic bag and put into the closet.
3. Explore the sequence of actions when working with a microscope.
1. Put a microscope with a tripod to myself at a distance of 5-10 cm from the edge of the table. In the opening of the subject table, send the light with a mirror.
2. Place the prepared drug on the subject table and secure the subject glass by the clamps.
3. Using the screw, smoothly lower the tube so that the lower edge of the lens is at a distance of 1-2 mm from the preparation.
4. See the eyepiece, see one eye, without closing and without clouding another. Looking into the eyepiece, with the help of the screws, slowly raise the tube until a clear image of the subject appears.
5. After the operation, the microscope is removed into the case.
Question 1. What are the magnifying devices do you know?
Manual magnifier and tripod magnifier, microscope.
Question 2. What is a magnifying glass and what increase does it give?
Mupa is the easiest magnifying device. The manual magnifier consists of a handle and magnifying glass, convex from two sides and inserted in the frame. It increases objects 2-20 times.
The tripod magnifier increases the items of 10-25 times. In its frames are inserted two magnifying glass, strengthened on the stand - a tripod. The subject table with a hole and mirror is attached to the tripod.
Question 3. How is a microscope?
In a visual tube, or a tube, a magnifying glass (lenses) is inserted into the luminous microscope. In the upper end of the tube there is an eyepiece through which various objects consider. It consists of a rim and two magnifying braids. At the lower end of the tube, a lens consisting of a rim and several magnifying braids is placed. The tube is attached to the tripod. The subject table is attached to the tripod, in the center of which there is a hole and a mirror under it. Using a light microscope, you can see an image of an object illuminated with this mirror.
Question 4. How to find out what an increase in the microscope gives?
To find out how much the image is when using a microscope, you must multiply the number specified on the eyepiece, by the number specified on the lens used. For example, if the eyepiece gives a 10-fold increase, and the lens is 20x, then the overall increase of 10 x 20 \u003d 200 times.
Think
Why with the help of a light microscope can not be examined by opaque objects?
The main principle of operation of the light microscope is that through a transparent or translucent object (the object of the study), located on the subject table, pass the rays of light and fall on the lens lens and eyepiece. And through opaque objects, the light does not pass, respectively, we will not see images.
Tasks
Learn the rules for working with the microscope (see above).
Using additional sources of information, find out which details of the structure of living organisms allow you to consider the most modern microscopes.
The light microscope made it possible to consider the structure of cells and tissues of living organisms. And now, he has already replaced modern electronic microscopes, allowing to consider molecules and electrons. A electronic raster microscope allows you to obtain images having permission measured in nanometers (10-9). You can get data regarding the structure of the molecular and electron composition of the surface layer of the surface under study.
Denisenko i.e.
Device of the light microscope.
The light microscope is most often used in biological, medical, veterinary and laboratory practice.
Some microscope features: Lights, resolving,
the field of view, depend on the diameter of the diaphragms and frames of the lens systems that limit the light streams entering the microscope optics. The microscope represents the optical system consisting of 2-strokes: 1 - the main, is provided by the lens; 2 - eyepiece. The lens forms a valid, enlarged and inverted image of the object under consideration. The resulting intermediate image is considered through the eyepiece, which is like a magnifier, additionally increases it. The final enlarged image observed through the eyepiece is imaginary and straight, located at a distance of the best vision from the eye of the observer (250mm). As a result, the microscope shows an image inverted relative to the preparation. To learn how to gain a general increase in the microscope, it is necessary to see how many times the lens and eyepiece increases. The product of these values \u200b\u200bis the overall increase in the microscope.
The course of the rays in the light microscope.
In the microscope differmechanical andoptical Parts. The mechanical part is represented by a tripod (consisting of the base and tube holder) and a tube-reinforced tube with a revolver for fastening and changing lenses. The mechanical part also includes: a substantive table for the drug, fixture for fastening of condenser and light filters, built into a tripod of mechanisms for coarse (macromechanism, macrovint) and thin (micromechanism, microvint) movement of the subject table or tube holder.
The optical part is representedlens , okular andlighting system which in turn consists of located under the object tablecondenzor Abbe and the built-in illuminator with a low-voltage incandescent lamp and a transformer. Lenses are screwed inrevolver , and the corresponding eyepiece, through which the image is observed, is installed on the opposite side of the tube.
Microscope device.
Mechanical part
Optical part
2. Monocular nozzle
1. Okular
3.revolver
4. Lens
5. Delivered table
9. Foundation
6.7. Condenser
10.State
8. Event with lens
11, 12, 13. - Drug holder
14. Macrolink
15. Microvent
16, 17. Preparator
18. Switch
19. Adjusting the lighting intensity
1. Answer the question.
For which I use magnifying devices.
- Answer: To study small size objects.
Manual Lup
2. Consider a manual magnifying glass. Write the names of its parts and the functions they perform.
3. Take pieces of pulp of tomato fruit, (watermelon, apple). Consider them with a naked eye. What do you leave?
- Answer: Soft thin skin and seeds.
4. Consider pieces with a magnifying glass. What do you see?
- Answer: Meat's cells.
5. Output
- Answer: Magnifier for so much that you can see cells that are not visible to the naked eye.
Light microscope
1) Examine a microscope. Find the main parts of the microscope. With the text of the textbook and the pattern, find out what their value.
2) Check out the rules of working with a microscope. Learn to set the light, achieve a good eye illumination.
3) Check the knowledge of the rules for using the microscope from each other.
4) Determine how many times the microscope increases the image of the object. (300 times. Depends on the microscope)
5) Explore the sequence of actions when working with a microscope.
