The qualities of an accountant as a specialist are: Personal and business qualities of the employee. Psychological aspects of the accounting profession
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 using it to examine the cellular structure of plants.
1. Examine a hand-held magnifying glass. What parts does it have? What is their purpose?
A hand magnifying glass 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 a distance at which the image of the object through the magnifying glass is most clear.
2. Examine with the naked eye the pulp of a semi-ripe tomato, watermelon, or apple. What is characteristic of their structure?
The pulp of the fruit is loose and consists of tiny grains. These are cells.
It is clearly visible that the pulp of the tomato fruit has a granular structure. The apple's pulp is slightly juicy, and the cells are small and tightly packed together. The pulp of a watermelon consists of many cells filled with juice, which are located either closer or further away.
3. Examine pieces of fruit pulp under a magnifying glass. Draw what you see in your notebook and sign the drawings. What shape do the fruit pulp cells have?
Even with the naked eye, or even better under a magnifying glass, you can see that the flesh of a ripe watermelon consists of very small grains, or grains. These are cells - the smallest “building blocks” that make up the bodies of all living organisms. Also, the pulp of a tomato fruit under a magnifying glass consists of cells similar to rounded grains.
Laboratory work No. 2. The structure of a microscope and methods of working with it.
1. Examine the microscope. Find the tube, eyepiece, lens, tripod with stage, mirror, screws. Find out what each part means. Determine how many times the microscope magnifies the image of the object.
Tube is a tube that contains the eyepieces of a microscope. An eyepiece is an element of the optical system facing the eye of the observer, a part of the microscope designed to view the image formed by the mirror. The lens is designed to construct an enlarged image with accurate reproduction of the shape and color of the object of study. A tripod holds the tube with an eyepiece and objective at a certain distance from the stage on which the material being examined is placed. The mirror, which is located under the object stage, serves to supply a beam of light under the object in question, i.e., it improves the illumination of the object. Microscope screws are mechanisms for adjusting the most effective 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. You should work with a microscope while sitting;
2. Inspect the microscope, wipe the lenses, eyepiece, mirror from dust with a soft cloth;
3. Place the microscope in front of you, slightly to the left, 2-3 cm from the edge of the table. Do not move it during operation;
4. Open the aperture completely;
5. Always start working with a microscope at low magnification;
6. Lower the lens to working position, i.e. at a distance of 1 cm from the 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 illuminate the field of view as much as possible and evenly;
8. Place the microspecimen on the stage so that the object being studied is under the lens. Looking from the side, lower the lens using the macroscrew until the distance between the lower lens of the lens and the microspecimen becomes 4-5 mm;
9. Look into the eyepiece with one eye and rotate the coarse aiming screw towards yourself, smoothly raising the lens to a position at which the image of the object can be clearly seen. You cannot look into the eyepiece and lower the lens. The front lens may crush the cover glass and cause scratches;
10. Moving the specimen by hand, find the desired location and place it in the center of the microscope’s field of view;
11. After finishing work with high magnification, set the magnification to low, raise the lens, remove the specimen from the work table, wipe all parts of the microscope with a clean napkin, and cover it plastic bag and put it in the closet.
3. Practice the sequence of actions when working with a microscope.
1. Place the microscope with the tripod facing you at a distance of 5-10 cm from the edge of the table. Use a mirror to shine light into the opening of the stage.
2. Place the prepared preparation on the stage and secure the slide with 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 specimen.
4. Look into the eyepiece with one eye without closing or squinting the other. While looking through the eyepiece, use the screws to slowly lift the tube until sharp image subject.
5. After use, put the microscope in its case.
Question 1. What magnifying devices do you know?
Hand magnifier and tripod magnifier, microscope.
Question 2. What is a magnifying glass and what magnification does it provide?
A magnifying glass is the simplest magnifying device. A hand magnifying glass consists of a handle and a magnifying glass, convex on both sides and inserted into a frame. It magnifies objects 2-20 times.
A tripod magnifying glass magnifies objects 10-25 times. Two magnifying glasses are inserted into its frame, mounted on a stand - a tripod. A stage 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 viewing tube, or tube, of this light microscope. At the upper end of the tube there 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, you can see an image of an object illuminated by this mirror.
Question 4. How to find out what magnification a microscope gives?
To find out how much the image is magnified when using a microscope, you need to multiply the number indicated on the eyepiece by the number indicated on the objective lens you are using. For example, if the eyepiece provides 10x magnification and the objective provides 20x magnification, then the total magnification is 10 x 20 = 200x.
Think
Why can't we study opaque objects using 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 stage and hit the lens system of the objective and eyepiece. And light does not pass through opaque objects, and therefore we will not see an image.
Tasks
Learn the rules of working with a microscope (see above).
Using additional sources of information, find out what details of the structure of living organisms can be seen with 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 been replaced by modern electron microscopes, which allow us to examine molecules and electrons. And an electron scanning 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.
Task 1. Examination of onion skin.
4. Draw a conclusion.
Answer. The skin of an onion consists of cells that fit tightly together.
Task 2. Examination of tomato cells (watermelon, apple).
1. Prepare a microslide of the fruit pulp. To do this, use a dissecting needle to separate a small piece of pulp from a cut tomato (watermelon, apple) and place it in a drop of water on a glass slide. Spread the dissecting needle in a drop of water and cover with a coverslip.
Answer. What to do. Take the pulp of the fruit. Place it in a drop of water on a glass slide (2).
2. Examine the microslide under a microscope. Find individual cells. Look at the cells at low magnification and then at high magnification.
Mark the color of the cell. Explain why the drop of water changed its color and why did this happen?
Answer. The color of the flesh cells of a watermelon is red, and that of an apple is yellow. A drop of water changes its color because it receives the cell sap contained in the vacuoles.
3. Draw a conclusion.
Answer. A living plant organism consists of cells. The contents of the cell are represented by semi-liquid transparent cytoplasm, which contains a denser nucleus with a nucleolus. The cell membrane is transparent, dense, elastic, does not allow the cytoplasm to spread, and gives it a certain shape. Some areas of the shell are thinner - these are pores, through which communication between cells occurs.
Thus, the cell is the structural unit of the plant
Students of general education institutions study the cellular structure of plant organisms in the sixth grade. Biological laboratories equipped with observational equipment use an optical magnifying glass or microscopy. Cells of tomato pulp microscope are studied in practical classes and arouse genuine interest among schoolchildren, because it becomes possible, not in the pictures of a textbook, but to see with their own eyes the features of the microworld that are not visible to the naked eye with optics. The branch of biology that systematizes knowledge about the totality of flora is called botany. The subject of the description are also tomatoes, which are described in this article.
Tomato, according to modern classification, belongs to the dicotyledonous pynopetalous family of Solanaceae. Perennial herbaceous cultivated plant, widely used and grown in agriculture. They have a juicy fruit that is consumed by humans due to its high nutritional and taste qualities. From a botanical point of view, these are polyspermous berries, but in non-scientific activities, in everyday life, people often classify them as vegetables, which is considered erroneous by scientists. It is distinguished by a developed root system, a straight branching stem, and a multi-locular generative organ weighing from 50 to 800 grams or more. They are quite high in calories and healthy, increase the effectiveness of the immune system and promote the formation of hemoglobin. They contain proteins, starch, minerals, glucose and fructose, fatty and organic acids.
Preparation of a microslide for examination under a microscope.
The preparation must be microscoped using the bright field method in transmitted light. Fixation with alcohol or formaldehyde is not done; living cells are observed. The sample is prepared using the following method:
- Using metal tweezers, carefully remove the skin;
- Place a sheet of paper on the table, and on it a clean rectangular glass slide, in the center of which drop one drop of water with a pipette;
- Using a scalpel, cut off a small piece of flesh, spread it over the glass with a dissecting needle, and cover the top with a square cover slip. Due to the presence of liquid, glass surfaces will stick together.
- In some cases, tinting with a solution of iodine or brilliant green can be used to increase contrast;
- Viewing starts at the lowest magnification - a 4x objective and a 10x eyepiece are used, i.e. it turns out 40 times. This will ensure the maximum viewing angle, allow you to correctly center the microsample on the stage and quickly focus;
- Then increase the magnification to 100x and 400x. At larger zooms, use the fine focusing screw in 0.002 millimeter increments. This will eliminate image shake and improve clarity.
What organelles can be seen in tomato pulp cells under a microscope:
- Granular cytoplasm - internal semi-liquid medium;
- Limiting plasma membrane;
- The nucleus, which contains genes, and the nucleolus;
- Thin connecting threads - strands;
- Single-membrane organelle vacuole responsible for secretion functions;
- Crystallized chromoplasts of bright color. Their color is influenced by pigments - it ranges from reddish or orange to yellow;
Recommendations: educational models are suitable for examining tomatoes - for example, Biomed-1, Levenhuk Rainbow 2L, Micromed R-1-LED. At the same time, use the lower LED, mirror or halogen backlight.
Even if you've never wondered what our everyday food looks like in extreme close-up, these photographs taken through an electron microscope can impress with their beauty and originality.
The fact is that a simple optical microscope is limited in its resolution by the wavelength of light. A smaller object will be bent by the light wave, so the reflected signal will not be able to return to the device sensor and we will not receive any information. It’s another matter when, instead of a beam of light, a stream of electrons is directed at an object - they are reflected, being comparable in size, and return to the bowels of the microscope, carrying with them various information about the object.
The only thing we can no longer do, having found ourselves so deep in the microworld, is see and distinguish colors, because... They are essentially not there yet. Therefore, all the bright colors presented in photographs taken through a scanning electron microscope are the fruit of the work of artists.
The broccoli flower, for example, looks like a tulip. So if your girlfriend is having a holiday and you forgot to buy flowers, you can just take the Broccoli out of the refrigerator and hold it up with a microscope :)
This alien planet is actually nothing more than blueberries. This is impressive, but will anyone eat blueberries after this? You give a whole Constellation of Yogurt at once!
A grain of salt is an example of a typical fractal shape. Both outside and inside there is the same crystal pattern.
Airy mint chocolate. As we can see, inside the small pores of the chocolate there are even smaller pores of the mint filling.
Strawberry. In the foreground is a crunchy, buttery seed. The vague fibrousness of this berry is now more than tangible.
Bird's eye chili pepper. The smallest representative of Chile looks solid and respectable, it can even be confused with a chocolate bar with nuts.
Raw meat . These are fibers! If it were not for the nutritional value of this product, it would truly be fabric for clothing.
Cooked meat. But after boiling and frying, the fibers crumble and break, which makes the work easier for our teeth and our stomach.
White grapes. Who would have thought that this homogeneous jelly inside the grape berry has such a porous character. It is probably the microporosity that creates that familiar tingling sensation on the tongue (as if bubbles are exploding).
Elegant and spicy, saffron tastes like bark from a wood processing plant. A piquant piece of gigantic wood.
The dried anise fruit resembles a cephalopod that has too many legs.
Coffee granules. Even knowing what it really is, it’s still hard to believe: these delicate sponges painted with hieroglyphs are amazing! If companies producing granulated coffee placed such photographs on their packaging, they would most likely be able to significantly increase their sales.
Sugar . Fractal brother of salt crystals. Who says that nature does not tolerate right angles?
Sweetener "Aspartame". So think about it: can an uneven, holey ball replace a polished cube or parallelepiped?
Tomato . Or is it still the honeycombs of red Martian bees? Scientists do not yet know the exact answer to this question.
The roasted coffee bean just begs to have a nut placed in its microcells and concreted on the outside with cream.
Romanesco cabbage. Perhaps this is the only product that resembles itself in the macrocosm.
Almonds are layers of heat-resistant carbohydrate slabs. If they were bigger, it would be possible to assemble a house.
If almonds are a house, then powdered sugar on a cupcake is upholstered furniture. Why does all junk food look so cozy?
Onion . As you can see, these are quite rough layers of sandpaper. That's what those who don't like onions will say. Others will note the resemblance to velvet carpets.
The inside of the radish crumbles into entire deposits of precious stones and volcanic rocks.
So, we are convinced that our everyday food, in a greatly exaggerated form, evokes strong associations with rocks, minerals and even space objects. What if one day - in the depths of the Universe - we discover entire planets and star systems consisting entirely of organic matter, including edible matter? We simply must be ready for this! The development of food spaces and the colonization of the edible landscape is the main topic of research by the famous American photographer and writer Christopher Boffoli. He called his collection “Inconsistency”; by the way, human figures were attached to the surface with agave nectar.
A repair team inspects a broken egg. Nothing can be done: now this hole will have to be repaired.
Banana roads promise to be the most convenient overpass for cyclists.
Robbery in the fig area. Previously, they didn’t even lock the doors there at night.
Be careful around melon holes.
The candy deposit scouts are moving with confidence and assessing the scale of the development.
Children play in the snow on cupcake hill. Make sure no one falls and catches a cold.
Waffle meadows are considered the best places for bees.
A worker brushing a sausage with dough. They say that Harry was too zealous with mustard, but that is not his fault: the unions decide everything.
