A device for demonstrating physical phenomena with your own hands. Topic: DIY physics devices and simple experiments with them. Operation of the camera, its results

Introduction
Chapter I. Work in the circle
§ 1. Organization of the circle
§ 2. Work program
§ 3. Working draft
§ 4. Completing the task
§ 5. Mass work of the circle
Appendix 1. Labor protection
Appendix 2. Laboratory circle
Appendix 3. List of basic physical and measuring instruments
Appendix 4. List of tools needed to build physical devices
Appendix 5. Household materials in the physical circle

Chapter II. Measuring instruments
§ 1. Measuring wedge 45
§ 2. Vernier model 46
§ 3. Measuring tape 47
§ 4. Range finder
§ 5. Ecker 48
§ 6. Compass 49
§ 7. Tablet and sight 51
§ 8. Astrolabe 52
§ 9. Altimeter
§ 10. Sextant 54
§ 11. Level 56
§ 12. Planimeter 57
§ 13. Pantograph 58
§ 14. Scales 61
§ 15. Rope scales 63
§ 16. Sundial (gnomon)
Appendix 6. Working with surveying tools in the field 68

Chapter III. Mechanics
Installation material 79
Parallelogram of forces 81
Construction crane 83
Force polygon
Inclined plane
Parallel forces
Levers
Puck as a lever
Equilibrium of arbitrarily directed forces
Blocks
Pulley hoists
Gate
Differential block
Set of plates for determining the center of gravity
Block scales 94
Law of inertia 95
Galileo's Trench 96
Device for demonstrating the free fall of bodies
Apparatus for demonstrating apparent weight change
bodies when falling
Cord for demonstrating the law of free fall of bodies
Trajectory of a thrown body
Carts for demonstrating Newton's 3rd law
More carts to demonstrate Newton's 3rd law
Steam gun
Centrifugal machine
Device for demonstrating centrifugal force
Watt regulator
A device to prove the Earth is flattening at the poles
Rotating vessel with liquids
Centrifuge model
Model of centrifugal awl
Maxwell's pendulum
Disc rolling on a magnet Tribometer
Friction angle
§ 37. Transmission belt friction
§ 38. Transmission
§ 39. Blocks and pulleys
§ 40. Wedge as an inclined plane
§ 41. Screw as an inclined plane
§ 42. Jack
§ 43. The simplest model of a water wheel
§ 44. Turbine built on the principle of using jet impact
§ 45. Water wheel for installation on a stream
§ 46. Jet turbine
§ 47. A more advanced model of a water wheel
§ 48. Model of a sailing ship
§ 49. Wind wheel
§ 50. Wind turbine 129
§ 51. Magnus effect
§ 52. Vingrotor 131
§ 53. Wingrotor with a helical surface 133
§ 54. Weather vane 134
§ 55. Pressure Proni 136
§ 56. Band brake 138
§ 57. Determination of work and power by means of a load
§ 58. Experiments to determine the efficiency of water and wind engines
§ 59. Paper glider
§ 60. Propeller
§ 61. Airmobile model
§ 62. Model of glider
§ 63. Equilibrium of bodies
§ 64. Addition of movements
§ 65. Transmission of movements
1. Belt drive
2. Friction transmission
3. Gears
4. Right angle gearing
5. Hooke's hinge
6. Worm gear
7. Differential
8. Crank
9. Crankshaft
10. Eccentric
11. Cam mechanism
§ 66. Toys
1. Acrobats on a wire
2. Gymnast on the horizontal bar
3. Clown on uneven bars
4. Carousel
5. Transparent balls
Cyclist
Rope cyclist
Rabbit
Duck
Blacksmiths
Turtle
Clown on uneven bars
Falling Clown
Top
Another toy Snake (conditions for its flight)
Flight qualities of kites
Protozoa snakes
Butterfly

Chapter IV. Oscillations and waves
§ 1. Vibrations of an elastic body occurring vertically and horizontally 176
§ 2. Elliptic vibrations
§ 3. Torsional vibrations
§ 4. Mathematical pendulum 177
§ 5. Seconds pendulum 178
§ 6. Mayo with a variable center of gravity
§ 7. Mechanical resonance
§ 8. Conjugate vibrations 179
§ 9. Spiral machine Field 180
§ 10. Strobograms 181
§ 11. Addition of vibrations ( graphic method)
§ 12. Addition of vibrations (optical method) 184
§ 13. Water waves 185
§ 14. Pendulum with escapement 189
§ 15. Hours 190
§ 16. Rocking boy 195

Chapter V. Acoustics
§ 1. Thread telephone 196
§ 2. Chladniian figures 197
§ 3. Transfer of vibrations in air
§ 4. Device for recording sound 198
§ 5. Gramophone 200
§ 6. Pictet mirrors
§ 7. Monochord 201
§ 8. Sound resonance 203
§ 9. Resonators 204
§ 10. Organ pipes
§ 11. Musical toys 205
1. Music box
2. Xylophone 206
3. Xylophone for orchestra 207
4. Metallophone 209
5. Triangle
6. One-string violin
7. Single string cello 210
8. Ordinary pipe 210
9. Reed nozzle or bagpipes 211
10. Pipe 212

Chapter VI. Solid
§ 1. Crystalline body213
§ 2. Stretching 216
§ 3. Device for determining thread strength
§ 4. Device for determining the strength of paper 218
§ 5. Deflection deformation
§ 6. Torsional deformation 221

Chapter VII. Hydrostatics
§ 1. Hydraulic press 222
§ 2. Pascal's device
§ 3. Fluid pressure from bottom to top 224
§ 4. Lateral fluid pressure
§ 5. Demonstration of an outflowing jet 225
§ 6. Reaction of the escaping jet
§ 7. Segner wheel
§ 8. Communicating vessels 227
§ 9. Fountain
§ 10. Hydraulic ram
§ 11. Hydrostatic balances 228
§ 12. Capillary tubes
§ 13. Water clock 229
§ 14. Chain water lift 231
Application. Glass processing 233

Chapter VIII. Gases
§ 1. Definition specific gravity air 241
§ 2. Cup barometer 242
§ 3. Siphon mercury barometer 243
§ 4. Aneroid model
§ 5. Melde tube 244
§ 6. Open pressure gauge 245
§ 7. Closed pressure gauge 246
§ 8. Suction pump
§ 9. Pressure pump 248
§ 10. Siphon model 249
§ 11. Air pump with Bunsen valves
§ 12. Bunsen water jet pump 251
§ 13. Device for demonstrating experiments with rarefied air 251
§ 14. Fountain in rarefied space 252
§ 15. Baroscope 253
§ 16. "Magdeburg hemispheres"
§ 17. Spray gun 254

Chapter IX. Heat
§ 1. Pyrometer 255
§ 2. Dubrovsky's device 256
§ 3. Installation for observing the expansion of solids under small temperature fluctuations
§ 4. Device for determining the coefficient of linear expansion 257
§ 5. Bimetallic plate 258
§ 6. Device for demonstrating the expansion of liquids when heated
§ 7. Device for determining the expansion coefficient of liquids
§ 8. Device for demonstrating the expansion of gases 259
§ 9. Thermoscope 260
§ 10. Device for determining the coefficient of expansion of air
§ 11. Device for determining x the thermal coefficient of air elasticity 261
§ 12. Model for demonstrating thermal conductivity 262
§ 13. Thermos 263
§ 14. Convection in liquids 264
§ 15. Central heating model 265
§ 16. Convection in gases 266
§ 17. Rotating lantern
§ 18. Demonstration of gyaga 267
§ 19. Balloon 268
§ 20. Calorimeter 269
§ 21. Boiler 270
§ 22. Steamer
§ 23. Distillation cube
§ 24. Steam turbine 271
§ 25. Hair hygrometer 272
§ 26. Hygrometer made of fir cones 273
§ 27. Hygroscopic house
§ 28. Chemical hygroscope 274

INTRODUCTION
In the fall of 1922, I was offered to take physics lessons at school No. 12 (experimental demonstration). I admit, I agreed to take this job not without hesitation, and when I got acquainted with the physics room, I simply gave up. In two cabinets, which were also not in a special office, I found several dozen instruments from Tsvetkov, Tryndin, Vyatka zemstvo workshops and other companies that supplied school equipment to pre-revolutionary schools. And in what form! The sets were scattered and most of the instruments were dilapidated. There were not enough lenses in optical instruments, the terminals were removed from electrical instruments, and even the winding was used for some household needs.
There were only a few days left before classes, and I kept walking around and thinking about how to teach physics in an experimental demonstration school in an empty place, when I only had chalk and a blackboard at my disposal.
On September 1, the first day of classes, having met the guys, I announced to the last two grades (VIII and IX) that those interested in physics should stay after school for a small meeting. I expected that, in the best case, there would be 5-10 such people, and they would constitute the asset with which I expected to start working. But to my great surprise, when I arrived in the hall where the meeting was scheduled, I counted more than five dozen children, and among them were junior high school students. Instead of the intimate conversation that I had planned, I had to hold a meeting, choose a presidium with a chairman, a secretary, an agenda for the meeting and keeping minutes. The meeting nominated me as chairman, but I refused, citing the fact that I was the speaker at this meeting. By this I wanted to show from the very beginning that in this matter I act only as an initiator and a senior comrade, and I adhered to this line throughout my work.
First of all, I had to explain the position of the physics room, and then I asked whether my listeners wanted to learn physics by cramming with chalk in hand, or whether they preferred to derive the laws of physics through experience and become familiar with its wonderful technical applications.
Of course, the answer was a unanimous statement that the audience preferred the second way.
- But how to do this? - the guys asked me.
In response to this, I told them how I myself and my friends studied physics, how we built instruments, what failures we had, how we overcame our own ineptitude and technical difficulties, how great were our disappointments and how happy we were if we achieved a successful solution. I said that a science like physics cannot be studied only from a book and passively watch the demonstrations of an experienced teacher. It is necessary to directly take an active part in the experience of manufacturing devices with my own hands. I reminded the children that many great discoveries in the field of science and technology were made by self-taught people using instruments they themselves made. Ampere carried out his classical experiments on electricity with homemade devices. The self-taught Faraday made his greatest discoveries using homemade instruments. Herschel polished glass for himself. Our Russian physicist Lebedev also determined the force of light pressure using a homemade device. A.S. Popov himself assembled the first spark telegraph. In a word, a significant part of discoveries and the vast majority of inventions are associated with the incidental creation of home-made devices. In our country, the issue of acquiring technical skills is of particular importance.
When I asked what practical conclusions the meeting would draw from my report, the guys unanimously decided to organize a circle to build physical instruments.
This decision was prompted by the fact that this form of work was well known to them - several circles worked at the school. Of course, some were listed only on paper, but there were also those who enjoyed the attention of students.
The decision to organize the circle, after a lively exchange of opinions, was written down in the minutes of the meeting as follows:
1) To improve theoretical qualifications in the field of physics and acquire technical skills in the processing of materials and the ability to use tools, a physics club is being established at school No. 12 of the MONO "In Memory of the Decembrists".
2) The intended goals in the circle are achieved through theoretical work (with a book) on the chosen topic and through the construction of physical instruments, for which a workshop is opened at the circle.
3) All members of the circle undertake to take an active part in the manufacture of devices individually or in groups. At the same time, everyone, using tools, as well as the material of the circle, can partially make devices or models for personal use.
4) To assist the head of the circle, the physics teacher, a board is elected consisting of a chairman, his deputy, a secretary and a manager of facilities (tools and materials).
The board develops internal rules for the circle, resolves disciplinary issues, distributes work among members and takes care of the timely replenishment of tool and material warehouses.”
I admit that at that time I was skeptical about this protocol, although I pretended to take part in the discussion of this document. Reality showed that my fears were not justified. The tasks outlined by the circle were carried out strictly, and in the person of the first chairman Misha Vysotsky, the supply manager Vasya Lisitsyn and the laboratory assistant Bori Odintsov, I found such wonderful assistants that for me there were no questions of discipline, I never cared about the availability of our tools and materials during the entire period of work We didn’t have a single device missing at school; the latter circumstance could also be explained by the fact that all members of the circle, according to the resolution of the organizational meeting, could freely use both the tools of the circle and its materials.
When this meeting ended, the newly elected board members approached me and asked me to stay for the first board meeting. At this meeting, only one issue was discussed - about tools and materials. It turned out that there used to be a training workshop at the school, and Vasya Lisitsyn said that some equipment still survived, and if I “click” on the head of the school, the circle can get this equipment, and as for the materials, it would be nice to get at least a small allocation from the school. “If this is not possible, then you, Pavel Viktorinovich, don’t worry,” finished Vasya Lisitsyn, “we will get everything without the head of the school, just you make us a list of the necessary materials.”
I talked with the head of the school, and he willingly met us halfway: I received from him all the tools that were at his disposal, and a small amount of money for the first equipment. The next day I handed the list of materials to the superintendent, and he read it to all classes with a request to take all the “junk” to school and hand it over to the 9th group student Vasily Lisitsyn. From that day on, our warehouse was always loaded with the most necessary materials.
Unfortunately, there was no special room for us (in the first year): the headmaster allowed us to work in the 9th grade with the obligation to clean it up after classes. Near the classroom in the hallway we placed Big cupboard with tools and materials, worked out a schedule, and my seven-year work in this circle began until the moment when work at a higher school completely absorbed my time.
Two years later, I started the same work at the Labor Skills Course at MONO. There were already two groups here - one from Moscow schoolchildren, and the other from teachers from different schools in the Krasnopresnensky district. The experience with the latter turned out to be successful. The People's Commissariat for Education decided to expand it, and work with homemade devices was included in the program of the Central Institute for Advanced Training of Public Education Personnel. For 5 years, until the dissolution of the Institute, I and the teachers gathered in Moscow
from all over the Union, built homemade devices. Then, in 1933, he took over the management of the physics office of the Research Methodological Institute of the Moscow Region and carried out the same work with teachers. Finally, starting in 1934, at the Central Institute of Polytechnic Education under the People's Commissariat of Millet, I was already conducting research work on home-made devices, using Metalconstructor parts as the main material.
The results of these works were published in a timely manner in periodicals and individual monographs were published. This last job I would like to summarize the results of twenty years of practice, and with a description of new models and some advice to help young teachers in their difficult daily work.

CHAPTER I
WORK IN A CIRCLE

When I started working in the Yag 12 school club and told the kids about homemade devices, I still didn’t imagine the full significance of this work. Only my further observations and experience showed in full all the positive qualities of this type of pedagogical work. Now, summing up many years of impressions, I can say that working in physical circles, in addition to acquiring technical skills, develops the hand, technical acumen, eye and observation. This work introduces a number of techniques and methods for processing various materials, their technological features, production secrets and technical recipes. In this work, the guys may even encounter technical calculations in practice for the first time, use their graphic skills for the first time, sketching a sketch, then drawing up a project and drawing a working drawing. Starting from the moment the problem is solved on paper, the question of the design of the model arises, and it remains in the spotlight until the end, thereby developing constructive abilities. Then, during the first experiments with finished devices, when design flaws are revealed, the question naturally arises about remaking the device; and with further improvement in order to save money. materials, labor or energy absorbed by the device, which requires complicating or, conversely, simplifying the design, the guys come close to inventive, creative work. In addition, in this complex labor process, the children get an idea of ​​the amount of physical and mental labor and effort that results in this or that device or machine.
Speaking about the significance of a home-made device, I cannot help but note one more observation, tested over many years by our school and circle work, which is the following: often factory-made devices, coated with varnish and nickel, and antique devices - even gilded, already shiny , their elegant appearance instills some kind of fear in their children. They operate with a homemade device boldly and are not afraid to break it; if it breaks, it’s no big deal, it’s easy to fix, and in such a way that it doesn’t happen again; While working with their device, the guys quite naturally come to the idea of ​​improving their model, replacing one part with another, etc.
Finally, the last consideration about making homemade devices is dictated practically. As a result of the development of our school network, the industry supplying school equipment, does not quite manage to cope with the assigned tasks. Some schools do not have the required set of equipment. Others, although they have equipment, do not fully meet the requirements of the school curriculum. At this point in time, students’ independent activities, not to mention their pedagogical value, are of considerable importance.

§ 1. Organization of the circle
So, the activity of the circle begins with a general organizational meeting, at which the future leader makes a short report. In this speech, he sets out in an accessible form the purpose and objectives of the circle and outlines the content and form of the work. It is best if the speaker attracts the attention of his listeners not so much with a story as with a show. Through a series of simple but quite convincing experiments, the manager must demonstrate the positive qualities of a home-made device, and it is advisable to do this in parallel on factory-made and home-made devices. Further, you can show such devices that are not available on the market, but are of great theoretical and practical interest and, moreover, are quite accessible for production in a circle. For example, a stenope, that is, a photographic apparatus with a hole instead of a lens; mirror stereoscope; a device that demonstrates the refraction of a beam at the water-air boundary, etc.
Along with demonstrating such devices, it is very useful to demonstrate several experiments. For example, show the burning of an electric light bulb connected to the city network by a small glass tube heated by a gas or alcohol burner. This experiment with the conductivity of red-hot glass usually always amazes the audience with its surprise, shattering the not always correct ideas about the resistance of conductors (Volume II). You can show the electrification of a comb, but not with light pieces of paper, which everyone does with childhood, but with a heavy stick or a large ruler - for this it should be balanced on some smooth base (for example, on a convex glass lampshade) and then set in motion, bringing an electrified comb closer to it. Or use the gramophone as a physical device, in this way: instead of a membrane, place a whole sheet of plywood with a gramophone needle driven into one of the corners on a rotating plate. The vibration of a large sheet of plywood is quite sufficient to clearly transmit the sound recorded on the record.
In conclusion, the chairman of the meeting proposes a pre-developed draft of the circle’s charter and, after discussion, its draft is approved by the general meeting.
The meeting ends with the election of the board or “officials” consisting of: chairman, secretary and manager of the material and tool warehouse.
If the circle consists of several groups, then each group must have a person responsible for the warehouse with tools and materials.
The chairman of the circle should in no case be the head of the circle based on the following considerations: the leader, conducting work in a team organized on the principle of voluntariness, should never lose sight of the fact that he is only a senior workmate, but by no means a class teacher . Remaining an ordinary member of the team, the leader thereby only increases the initiative of the circle members, does not restrict freedom of judgment, and work discipline in the circle is supported not by administrative measures, but by his authority and personal example. As our experience has shown, it is very useful if the leader himself takes on a topic and works on it along with the rest of the students. In a well-established circle, only at first the leader is usually overloaded with work and often really does not have time not only to give detailed explanations, but also to answer questions; but then, when work settles into a calm course, the manager will always have free time. The author of these lines often used it both in children’s circles and when conducting practical classes with adults, in order, along with the other members of the circle, to build some kind of device, set up another experiment, etc. and this never interfered general work; The example of a leader is always instructive.
As for authority, it can never be won only by rigor, but is acquired by a leader mainly due to his qualifications. The manager must not only know physics, which is quite enough for classroom work, but also must have work skills. No professional skill is required, but he must be familiar with working wood, metal, glass and cardboard using ordinary hand tools. If the circle has lathes, planers, and drilling machines, then the leader must not only become familiar with their operation and control, but must also learn how to operate them.
Circle tasks. 1. Raising the level of theoretical knowledge of members of the circle on exact sciences and technical disciplines. 2. Mastering the technique of independent experimentation. 3. Acquisition of polytechnic skills in processing materials and the ability to use tools. 4. Independent production and repair of devices for the physics room. 5. Stimulating inventive thought.
of the circle and the school, the degree of preparedness of the children and, finally, the inclinations of the leader himself, a great variety is possible here, but as an example I will allow myself to cite the “Charter of the physical circle of school No. 1 of the Japaridze district of Baku”, as it is given in the book of the head of the circle, see. N. Shishkin, “Circle of Young Physicists”, M. 1941.
Circle structure. 1. Students are accepted into the circle on the basis of complete voluntariness. 2. The head of the circle is a physics teacher. 3. Members of the circle general meeting elect:
a) the head of the circle,
b) foremen of individual brigades,
c) the manager of the material department,
d) two toolmakers for carpentry and plumbing tools,
e) responsible for the condition of workplaces and the entire workshop premises,
f) the editorial board of the intra-circle newspaper,
g) the editorial board of the scientific and technical bulletin.
Note. Toolmakers have the right, if it is necessary to repair a tool, to assign any member of the circle to repair the tool.
Organization of the work of the circle. 1. Work on the manufacture and repair of instruments in the circle is carried out on the principle of voluntary association of circle members into teams or individually.
2. The composition of the team is maintained only for the duration of the manufacture of a particular device, after which the team can remain in its previous composition.
setting or change it.
3. The distribution of work is mainly carried out according to the wishes of individual teams, but if work is offered by the circle leader, its execution is mandatory.
4. Work in the laboratory and workshops is carried out by members of the circle in their free time from classes on all days of the week from 10 am to 10 pm.
5. After making the devices, the latter are demonstrated at the general meeting of the circle by the team that made them.
6. Members of the circle are required, in addition to conducting practical work, to participate in the preparation and conduct of scientific reports.
7. Each member of the circle is obliged to present at least one device made by him personally for the reporting exhibition by the end of the school year.
8. Each member of the circle is given the right to use the equipment of the workshops and laboratory for his personal work.
9. At the end of the school year, the circle organizes an exhibition and demonstration of the devices made.

§ 2. Work program
Despite the fact that the circle works on the principle of voluntariness, i.e. free entry and exit from it and freedom to choose the topics on which the members of the circle work, as well as methods and forms of work, the leader, before starting to organize the work, must seriously think and outline the main points in advance work program and those issues that should and can be resolved in the process of work. At this moment, some difficulties inevitably arise, since the two main reasons that led to the emergence of the circle - the underequipping of the physics room and the requests of the children caused by technical interest - collide with each other. You cannot refuse to replenish your office with the necessary equipment, but at the same time you cannot neglect the requests of the guys. Therefore, when drawing up a work program, the manager requires great tact, ingenuity and restraint in order to reconcile these contradictions that may arise when deciding on the program, without disturbing the balance between them. Therefore, in order to solve this problem painlessly, it is useful to agree in advance on the working hours of the circle necessary to repair and put in order the factory instruments of the physics room, then periodically check and prepare them for demonstrations and laboratory work in practical classes. Of course, when planning this part of the work, it must be distributed in such a way that each class devotes part of its working time to working with those instruments that they will need for the classroom study of the physics course.
The next part of the program should satisfy the children’s own needs. At the same time, we must not forget that the guys, not knowing their technical capabilities, often set themselves clearly impossible tasks. It would be a mistake to include all their requirements entirely in the program. N. Shishkin says absolutely correctly that “we must warn against an overly exaggerated idea of ​​​​the capabilities of the guys.” Of course, solving complex problems in instrument making, creating completely original designs is beyond their reach, but they can cope well with the independent design of individual units and parts of the device, various devices that facilitate and speed up work.It is in this direction that their thoughts must be forced to work.
Solving individual technical problems in a relatively short period of time creates a feeling of great satisfaction; the young author sees concrete results of his creative experimental and rationalization work, and interest in it grows.
On the contrary, this interest can be killed if you give a teenager a task that is beyond his strength. And a 15-year-old boy, joining the circle, right off the bat wants nothing more and nothing less than to build a six-lami receiver. Of course, assembling such a ‘receiver’ using ready-made parts according to this scheme with an experienced leader is a simple matter, but is the pedagogical value of such work great? We will rightfully answer: not much. Questions not only physical foundations and the essence of radio, but I don’t even master the installation technique! It’s in such work, and if after that you entrust such an “engineer” to independently assemble a simple regenerator using a ready-made circuit, he will not cope with this work.
Therefore, we must not forget when drawing up a program that the first and main requirement that must be pursued in every properly organized pedagogical process (and work in a circle is such a process) is the path from simple to complex. And how often do leaders, wanting to show off the work of the circle or obeying the demands of the children, set or agree to solve impossible tasks.
Of course, this is unacceptable, firstly, because it does not lead to the intended goal, and secondly, as experience shows, the guys, having failed to complete the task, are disappointed in their abilities, they give up, and they leave the circle . The consequences of this are the most undesirable: firstly, they lose the desire to study technology for a long time, if not forever, and secondly, they have an unhealthy effect on the surrounding mass, and as a result, the circle begins to crumble. We especially warn young leaders against this danger. N. Shishkin makes the same warning in his interesting work. He says1) that when satisfying children’s requests, “one must also take into account the fact that the interest shown by a teenager in one or another branch of science is often accidental, based on a general “fashionable” hobby.” Let’s say that if the guys are especially interested in radio engineering, then some of them, not having even the rudiments of knowledge in this area, having never built even the simplest radio receiver, will strive to take on a topic in radio engineering that is clearly beyond their capacity.
Often, when conducting conversations in a simple, unconstrained environment, I explain to the guys that in this case, the study of radio engineering must begin with the basics, and switch your abilities, your desire to work to another topic. I tell you how the simplest physical laws find application in the most complex modern machines, show interesting, outwardly impressive experiments and ask you to explain them. The student quickly becomes convinced that he does not know many simple things, but knowing them is not only interesting, but also necessary.
As a rule, after such conversations there are no more conversations about topics prompted by a simple, unfounded hobby, and the student asks for help in choosing a different topic for work.
The second danger when drawing up a working program is that it is overloaded with purely technical applied topics to the detriment of the physical device. Numerous surveys of school clubs and children's technical stations have shown us that in the overwhelming majority of cases, naked technicalism prevails in these extracurricular organizations and very rarely attention is paid to physics itself. And the very name of the circles indicates to us the predominance of technology. We have a large number of aircraft modeling and radio engineering circles, there are electrical engineering circles, communications circles, photography circles and very few physics circles. And even in such a leading institution as the Central Children's Technical Station, which has at its disposal a large number of laboratories and rich equipment, until recently there was no physics club.
Of course, in these circles they talk about physical laws, but as a rule they are taken on faith, dogmatically and are not subjected to either theoretical analysis or experimental verification. But this is wrong and unacceptable in the school circle. We must not forget that theory and practice are closely dependent on each other and develop in parallel. Therefore, it would be the same mistake to study one theory in school circles. This is also unacceptable because concrete thinking, characteristic of teenagers, will not tolerate exclusive abstraction, and work in a circle can take the form of a bad lesson if the circle does not disband at the very beginning of classes. In order to combine these two pressing issues, the leader of the circle must be a comprehensively educated person and have a large stock of technical skills. Unfortunately, in most cases this is not observed. And the leaders of the circles, having taught the children to understand radio circuits, introduced them to some assembly techniques, or taught them how to mechanically take satisfactory photographs, consider their task completed without even touching on the physical essence of the phenomena. We had to deal with this even in one of the central institutions of Moscow. Young technicians studying design work in technical circles are often completely unprepared theoretically and are not aware of the physical phenomena that they are trying to use for their invention. Their projects are sometimes striking in their illiteracy. For example, one inventor in my presence suggested building an all-metal airship and then pumping air out of it to rise, then it would be even lighter than one filled with hydrogen. This shows that the leadership was not deep enough and competent enough.
Therefore, when drawing up a program, that is, choosing topics, the manager needs to take these considerations into account.
Finally, the program is drawn up, the topics are outlined; then the question arises of how to plan this work, i.e., how to distribute topics between members of the circle so that there is no overload of some and underload of others, and this will certainly happen if the leader, due to inexperience, relies on his own strength and starts work at the same time with the whole circle. We say this because our experience and observations have shown that many people usually enroll in circles. And it is beyond the power of one leader to work simultaneously with all those who have joined the circle, and if the premises for the work of a large circle are quite sufficient, then a large number of leaders will not help the matter - they will only interfere with one another. As a rule, the number of people working simultaneously in one group should not exceed 15 people (we have also compiled lists of tools for this number).
Therefore, when planning work in a large circle, before starting work, it is necessary to divide it into groups, guided by age and interests, then draw up a firm schedule for all groups and only then begin work.

§ 3. Working draft
Any idea related to a technological process, before receiving material design, must go through a sketch, design, design and, finally, a working drawing, and only after that the processing of the material begins. Work in circles in the manufacture of physical instruments and technical models should go through the same stages. Usually, when designing, circle leaders go in the direction of least resistance and pay for it later when, in the process of manufacturing the device, they encounter great difficulties. This happens because managers very often lose sight of the fact that the technological process when building homemade devices is sharply different from technological process at the factory. Given the paucity of our literature on home-made devices, the manager, to draw up a project, turns to a physics textbook or a factory catalog and, using them, often without explanation, draws up a design for the device. We often come across such cases when a physics teacher, who is also the head of a circle, takes a finished device from the physics classroom, disassembles it with the guys, and then they copy it with minor changes.
Drawing up a project in this way, of course, is a relatively simple matter, but then constructing a device according to this project is almost impossible.
When building a device at a factory, the design engineer selects from the necessary materials first of all those that are most suitable for solving a given technical problem; in doing so, he is guided, firstly, by their technical properties, secondly, by economic conditions, thirdly, by his own weapons, i.e. here he means the equipment of his factory (in relation to his machines he draws up a project), and, finally, fourthly, he takes into account the principle division of labor.
The conditions for making devices in mugs are completely different. Here we most often do not have the necessary materials at hand, which is why, willy-nilly, we have to use surrogates, scrap materials and other materials. On the equipment side, at best we can count on lathes and drilling machines, and everything else is made by hand; finally, we cannot carry out a strict distribution of labor - in a circle one and the same person is a mechanic, a carpenter and a painter, and at the same time an engineer-constructor. These conditions must be taken into account when developing the project.
Let's explain this with an example. Let's say you need to build an electromagnet. As you know, the core of an electromagnet requires soft, clean iron that can quickly demagnetize. Of course, in our warehouse of materials there is not always such iron of the required cross-section. Therefore, you will have to replace it with something else: sheet iron or tin. To do this, they need to be annealed, descaled, and then, cutting rectangular strips, put them on top of each other so that they form a prism of the required cross-section. Then bend this prism into three bends to form a U-shaped core. After this, the poles should be carefully filed in a vice and one plane (Fig. 1 i) - For winding, turned wooden coils are usually put on the core, but in this case such coils will not suit us, and making them from wood or even cardboard is a difficult matter. Therefore, in order to prevent the wire from sliding off the core when winding, we will make the following device: we will cut three plates from the same tin - one slightly longer, and two approximately equal to half of the core plates. We insert the long one inside the core and bend its ends from above towards each other, attach the smaller ones to the sides and. bend their ends to the sides, and then wrap two or three layers of paper with glue and get a core made of tempered soft iron, without wooden coils, but with sides that protect the winding from slipping (Fig. 1 b, c and d).
If the electromagnet has to be mounted on a stand with the poles facing up, then before winding, you can place plates bent to the side with holes for screws on both sides before winding.
Consequently, it is possible to design and build an electromagnet, the manufacturing process of which will be very different from an electromagnet made in a factory.
Let's take another simple example, when you have to change the technological process solely due to the lack of necessary equipment.
It is required, for example, to build a very ordinary button for an electric bell. As you know, this contact consists of two springs, enclosed in a turned wooden body, consisting of two halves, screwed onto one another. To make this body, you need a lathe, and one that can be used for screw cutting on wood. Of course, not every circle has such a machine. In this case, we will do this. cut out parts A, B and C from plywood (Fig. 2), and then cut out two plates D from brass. Attach a button to one plate with a screw and then assemble the device in this way: attach one plate to circle C, and another to circle B and then connect all three parts (Fig. 3) with screws. The D plates will serve as contacts.
Let's take another example of a successful design, solved by young technician Yuri Golubev from the city of Alapaevsk in the Urals when installing an electric bell. Two thick wire nails or iron screws are driven into a wooden beam, connected on the opposite side by an iron plate. The nails are wrapped with insulated wire. Then an anchor made of sheet iron of the shape indicated in the drawing with a hammer and an iron plate on top is attached to the left side of the block to increase the mass of the anchor. At the opposite end of the bar, a bell cup is fixed, to which the hammer touches (Fig. 4).
To connect the bell to the network, you need to secure two terminals on the block, and the device is ready.
By citing these designs as examples, I do not at all intend to assert that these are the only correct solutions and there cannot be others. On the contrary, you can come up with dozens more options,
but we must remember that good decision The problem lies not only in its correct answer, but also in the fact that of all possible solutions this is the simplest.
When solving new design problems, as a rule, the first solutions always turn out to be cumbersome, complex and clumsy. For example, the first machines of Polzunov and James Watt were much more complex than the machines built subsequently. At the same time, cars acquired simpler and more elegant shapes every year. The efficiency also increased.
Remember the history of the bicycle. What a clumsy, inconvenient and fragile structure it was, and how it was then improved year after year until it acquired the simple outlines of our days. The same can be said about a steam locomotive, a car, a gramophone, an airplane and a hundred other machines.
When designing and then building homemade devices, you cannot stop at one form. It needs to be simplified, since the most visual and most convincing form in the pedagogical process is the simplest form. But this simplification, of course, should not be done at the expense of the efficiency factor, but on the contrary, the shape should be changed in such a way that the efficiency increases with each new model.
These two demands seem to be in contradiction to each other; a true inventor and designer requires skill, talent and technical acumen to find the most appropriate solution to a problem. Therefore, in our work there can never be a final solution. Each appliance should be considered as a temporary form only. When modeling, each individual improvement often seems to the author to be the final, finishing touch in solving the problem; in fact, this improvement should be considered only as a separate step in the general stream of forward movement.
This attitude towards work is instilled with great difficulty. When I started working at the Central Institute of Polytechnic Education, my laboratory assistant, who had served there before me, at first categorically rejected my work methods. It seemed to him that the solution to the technical problem lay only in building a functioning device. And it often happened like this: I tell him the idea of ​​the device, sketch out a drawing, explain what materials to use and how to build it. He performs the device in kind. The device works and shows what is required of it, but during the experiments I notice the complexity of the design, the excessive consumption of materials and energy, and after the tests I say: “Tear it down, we’ll build a new one.”
My order was initially met by my assistant with a categorical refusal, with remarks that “building only to then destroy is sabotage.”
But I broke the devices and then built new ones. My subsequent models acted better and more clearly each time. Finally, my co-worker was convinced that I was right. He saw that I was not “sabotaging”, but on the contrary, I was striving to achieve the best results with the least amount of money and energy. Then my comments were met without any objections.
If simplicity is desirable in every design, then for a homemade device it is mandatory. But at the same time, it must be noted that in search of the most simple solution One should not lose sight of the increase in efficiency or clarity of operation of the device. From this point of view, perhaps not bad and executed with great care, some devices by Dubrovsky, Drenteln, Tochidlovsky, Krasikov, etc. are very good for an odp-nochka teacher who does not have assistants at his disposal and requires minimal means for their execution and time, but for group work (cabbage soup is not suitable. These are only material illustrations, “flying diagrams” according to N. Shishkin, and not instruments.
As an example, our drawings (Fig. 5 and 6) show a lever from the book of Prof. Tochidlovsky and a device from Krasikov’s book for demonstrating the equilibrium conditions of a floating body. The first setup, as you can see, consists of a bar, a weight and a spring scale, a table and a chair are used as tripods, the second device is made of one half of a wooden egg, a shot and a piece of wire with a wax ball 1). These devices cannot be denied ingenuity, they are quite visual, and, finally, if the teacher does not have at his disposal either assistants or visual aids, they fill this gap to some extent, since assembling such installations from scrap material is a matter of five minutes, but they are not suitable for our purpose. Indeed, which of the guys can be captivated by such devices? We must not forget that the children are attracted to our circle by the opportunity to build cars, which is why they always set out grandiose plans at first, but instead they are offered a wooden egg.
The devices coming out of our workshop should really be devices, and not abstract circuits hastily cobbled together from the first available material.
But we must not forget that the center of gravity of our activities in the circle lies in the experimental study of physics, and, therefore, when building instruments, we are interested in saving time for this. Unfortunately, most physical devices are labor-intensive and require many hours of labor to manufacture, especially if technical skills are weak. Therefore, it is necessary, at every opportunity, to use ready-made parts, semi-finished products and blanks made in carpentry and plumbing workshops. It is advisable to build devices from a ready-made standard.
1) It must be said that this device is not an original invention of Krasikov, it was borrowed from Dubrovsky’s book.
The school is obliged not only in words, but in practice to show the children positive sides standardization; The easiest way to do this is in circle work. Who of the physics teachers who has ever been involved in the manufacture of instruments does not know how much precious time is consumed by the construction of some kind of stand, rack, bar, etc., and what an annoying hindrance is sometimes the lack of a simple lens, insulated wire of the required cross-section, etc. etc. The introduction of standardization in the circle greatly simplifies matters. In fact, having at our disposal a set of semi-finished products and, when designing, taking into account the need to use the same lens, electromagnet, block, transmission wheel in a whole range of devices, we will significantly save ourselves time, labor and money, and in addition, thanks to Due to the interchangeability of parts, we can use them from devices that have gone out of use.
For wood at the Central Institute of Polytechnic Education in 1933, a standard was developed, approved by the section teaching aids GUS (July 31, 1932) and tested in mass work. This set can be made in the school's woodworking workshops or ordered externally.

It is useful to add here a set of blocks carved from wood or sawn from plywood (Fig. 7). The most suitable diameters are the following (dimensions are given for internal diameter): No. 1 2.5 cm, No. 2 5 cm, No. 3 10 cm, No. 4 15 cm, No. 5 20 cm and b 25 cm.
These parts can be used to create installations for demonstrating blocks, levers, inclined planes, gates, gears, etc.

As an excellent standard material, we warmly recommend Metallokonstruktor parts1. These kits contain a significant range of parts that we can use in a wide range.
The standard consists of the following parts (Fig. 8 - 14).
1. Strip iron (3, 5, 7, 5. Small flat plate. 9, I and 25 holes). 6. Large box cooker.
2. Wide strip iron. 7. Small box cooker.
3. Angle iron (5, 11 and 25 8. Overlay,
holes). 9. Corner.
4. Large flat stove. 10. Yoke" (U-shaped bracket).
Rice. 15
Rice. 16
11. Zeta bracket.
12. Scarf (corner).
13. Headscarf.
14. L-shaped scarf.
15. Bracket.
16. Yoke.
17. Yoke.
18. Zeta bracket.
19. Corner.
20. Straight axle (shaft 50, 65, 90, 115 and 205 mm).
21. Crankshaft (handle).
22. Installation ring.
23. Parts that replace subtypes.
24. Articulated coupling.
25. Wheel with a flat rim.
26. Block.
27. Disks (faceplates).
28. Railway wheels.
29. Roller with free bushing.
30. Gear wheel.
31. Worm.
32. Rack.
33. Gear.
34. Face gear.
35. 36. Face gear.
These parts are an excellent material for the construction of physical devices and especially technical models (Fig. 15 and 16).

§ 4 "Completing the task
Once a project has been drawn up, it is useful to subject it to general criticism. As my experience has shown, very often the guys make good suggestions that simplify and improve the original design or technological process. The expediency of this is confirmed by the experience of other teachers; Moreover, the discussion of the topic begins even before the drafting. So, for example, N. Shishkin in the book we quoted says:
“Once the topic is chosen, we discuss the basic requirements that the device must meet. Then, without fail, the student or the entire team gets acquainted with the relevant literature, not only popular science articles, brochures and textbooks, but also other works.
Manufacturing a device immediately, so to speak, taking into account all the details of the design and their interaction, due to insufficiently developed spatial imagination, is inaccessible to students. In addition, it is irrational to carry out experimental work that reveals all the design flaws on a finished device, since it is necessary to change already completely finished parts. Therefore, the so-called “flying circuit” is almost always pre-assembled from unfinished parts.
On the “flying diagram” all the shortcomings of the device are identified, errors are eliminated and correct design solutions are found, and the necessary measurements are made.
When analyzing even obvious errors, great pedagogical tact is required. On the one hand, it is necessary to prove their inevitability due to a combination of certain reasons, on the other hand, to help find the path to the right solution, without suggesting it in its entirety, but only outlining milestones towards achieving the goal....
Most often, each project in nature is carried out by one member of the circle, but if the task is complex and requires a lot of time to complete, then the work should be distributed among several participants. This, firstly, will save time on construction (or rather, speed up the process, since the number of man-hours remains the same), and secondly, it will provide an opportunity to introduce students to the principle of division of labor through live experience.
A caveat needs to be made here. It is unacceptable to divide labor, as is done in large production. We, members of the circle, are not ready for narrow specialists; our goal is to increase and deepen the knowledge given by the school, the main goal of which is to educate a versatile, harmonious personality; this goal remains mandatory for us. Therefore, introducing the children to such an organization of work, where the division of labor gives the greatest production effect, the leaders of the circles should transfer each of the circle members from one type of work to another as often as possible. We cannot have carpenters, cabinetmakers, mechanics, turners, polishers, etc., but all the guys must go through all types of work encountered in the modeling and construction of devices, that is, each of the participants in our cooperation must be familiar with all technological processes taking place in our laboratory.
“But when assigning a certain task, demanding high-quality work, we must take into account the real capabilities of the student - his age, ability to organize his work, etc. - and do everything possible to help students acquire craft skills.
Often, beginners, having received a task, strive to immediately take up the instrument and get to work; plan, saw, hammer nails - in a word, show your activity, which, by the way, is short-lived. As a result, devices appear that are made sloppily and ill-considered.
Unfortunately, a study of the work of circles shows that in most cases too little attention is paid to the appearance of the models being produced. There are also many managers who hold the completely incorrect view that the only purpose of a model is to show a physical phenomenon or simulate the operation of a machine, and if the model works well, then nothing more is required of it, and the work is considered completed.
This view is completely wrong on its merits. Grinding, polishing, painting, chrome plating and, in general, any external finishing of instruments and parts is carried out not only to give them a beautiful appearance, but mainly for strength and increased resistance.
We paint and coat the metal with nickel to protect it from corrosion. When this cannot be done, we carefully grind and then polish the surface, since during these operations the product is, as it were, covered with a compacted layer of the same metal, protecting it from rust.
The external finishing of rubbing parts is caused by the need to reduce friction - trunnions, shafts, bearing shells are scraped down, and balls and rings in ball bearings are polished to a mirror shine not at all for beauty, but in order to reduce friction, make the machine run smoothly, increase its strength and service life service, reduce the amount of lubricants; in a word, all these processes of external finishing of a thing are caused mainly by economic reasons.
The same must be said about wood. Sanding, painting, varnishing and polishing increase the service life of finished products.
Technology has now given us a variety of paints and varnishes that protect wood and metal from damage.
If these coatings are necessary for products such as furniture, utensils and household items, then to an even greater extent these protective measures should be used by builders of machines and physical devices, they are expensive, and therefore require more reliable protection. Before the discovery of nickel in the 18th and first half of the 19th centuries. Expensive physical devices were very often plated with gold, and even now many factories gild or silver critical parts of the devices.
In the work of our circles, the conditions remain the same, and, unfortunately, we observe the fulfillment of these requirements only as an exception. Much more often we see the opposite: for example, quite often in radio engineering circles, the installation of complex radio receivers is carried out on plywood, and the plywood is not even sanded or painted, but is used in the form in which it was received from the factory. It is unacceptable that expensive parts such as lamps, variable capacitors, self-induction coils are somehow attached to dirty, warping plywood that does not protect these parts from damage.
The same applies to other devices. To verify this, take a look at the attached photographs (Fig. 17, 18, 19). In the first of them we see steam engine with an oscillating cylinder.
This machine works, therefore, the steam inlet window and exhaust holes are well adjusted, in a word, the most difficult part
The work was done satisfactorily, but the appearance of the device leaves much to be desired. The same must be said about electromagnetic and mechanical hammers.
Not only is a sloppily constructed device not only not pleasing to the eye, it also necessarily works poorly and does not last long. Carelessly fitted parts soon fall apart, moisture gets into the cracks, dust and dirt accumulate, and the rubbing parts very soon refuse to work. Therefore, from the very beginning of work in the circle, it is necessary to accustom the children to careful preparation and finishing of all parts of the device. It is necessary that the so-called velvet saw, sandpaper, emery, blued, scraper and paint brush, together with paints and varnishes, are the same important tools and materials in our technological process as the primary and main tools. Along with rough processing of metal and wood, it is necessary to familiarize children with the final finishing of products and instill in them the awareness that this part of the technological process is just as necessary as the previous one.
“The design of the device, its finishing has enormous educational significance in a circle.
If, when making a device and setting up an experiment, students are driven by the desire to achieve this or that effect, then finishing and external design requires the ability to make good, beautiful things, which does not come immediately, but is achieved through hard work. It should be emphasized that it is in this part of the work, on the device, that foam qualities such as patience, perseverance, perseverance, and a love of independent work are cultivated.
Convinced from his own experience how much effort it takes to make a device, the student begins to appreciate the work of others and treat finished things with care. This is how an economic, careful attitude towards public property and conscientiousness in relation to the task are brought up"1,).
Finally, one last note. Despite the fact that these days circle work has gained a large scope, for our teachers this is a new thing: its organization, methodology, content and themes, and finally, the forms of work raise a number of questions that are still far from resolved and unclear for the people in charge of this business ; Therefore, in order to accumulate material, it is necessary to keep accurate records of the work. This is also necessary from the point of view of the pedagogical impact on the children, so that they see and can evaluate the growth of their knowledge, skills and experience, and this is only possible if there is a thorough and systematic record of work.
Current records are kept by the circle secretary; he carefully, without omissions, records all current work mug. In this case, accounting should not be complicated by cumbersome forms, but it is better to use the following simple scheme.

To the question, what did you do? It would be desirable to receive a comprehensive answer. The same should be said about the last column, where the leader supplements the circle’s chronicle with his comments. If this diary is kept with pedantic precision, then already at the end of the first academic year there will be the most valuable material for summing up the experience of the circle.

§ 5. Mass work of the circle
Any social organization is viable only when it relies on the masses in its work. This axiom is also mandatory for group work. After all, each circle is organized among the mass of students, lives in this environment and draws new personnel from this environment. Therefore, it would be wrong if members of the circle become isolated in their work. The connection of the circle with the life of the school will give the circle participants the opportunity to make useful practical work apply the knowledge and experience gained in the circle - repair the school electrical wiring, make a number of instruments for the physics classroom and chemical laboratory, install an electrical alarm in the school, equip the classroom with projection lights, install a radio, etc.
To carry out technical propaganda, the circle first of all demonstrates the results of its work in the classroom.
When the device is manufactured and tested, it should be shown in a mug with all experiments. After the demonstration, again, as at the beginning of the work, the question should be raised about the quality of the work, what design features can be added to the model, what can be simplified in it in order to achieve even greater clarity of experiments, etc. Usually, passionate debates flare up in connection with these issues, and the model is subjected to severe criticism. Among these comments there may be very practical considerations, on the basis of which adjustments can be made to the device. Then, after corrections, if necessary, the device should be shown in the appropriate class during a physics lesson. Here, at your first experience, you will be convinced that a home-made device is more accessible to the masses of students than a ready-made factory one, since it arouses more interest, as if it were made by one’s own comrades.
It is very useful to participate in the wall newspaper, reflecting the activities of the circle there, to organize technical evenings among students not included in the circle, to end each school year with an exhibition and conference with the involvement of representatives of neighboring schools and the public.

Annex 1
OCCUPATIONAL SAFETY AND HEALTH

If Soviet laws pay so much attention to the labor protection of adult workers in manufacturing enterprises, then this applies even more to the creation of such working conditions for adolescents so that they do not in any way affect their health. Speaking about the leadership of a physics circle, we cannot ignore this issue.
All mechanical machines, if they are at the disposal of the circle, pose a danger if handled carelessly; the same must be said about the electric current of the city network.
If you touch the conductors with dry hands, stand on dry ground, and also wear galoshes that do not allow electric current to pass through, then the resistance will be so great that the current will not reach a dangerous value. But this does not always happen in practice.
Our hands are almost always covered with moisture. You can also never guarantee that the floor and walls you touch are dry. Therefore, you should not touch live wires with wet hands. And it would not be bad if, when working with current, you used rubber gloves and at the same time put on rubber galoshes. But even with these precautions, teenagers should not be allowed near electrical wiring. You need to make it a rule to never touch live wires.
We strongly insist that during any work with electrical wires they were disconnected from the network.
If your school does not have a master switch for the entire network, it is important to distribution box unscrew and remove the safety plugs, and not just one, but both.
If you are working with a switch, then in order not to allow current to pass through you, you need to unscrew the lamp with which it is connected. If you are working with a lamp socket, you must first make sure that the switch does not allow current to pass into the socket.
A particularly dangerous place when repairing a network is the plug, since accidental contact may result in a short circuit. Therefore, when installing the plug, be sure to turn off the radio. And in general, you need to take it as a rule: when working with wires, the current must be turned off in two wires, and only in this case will you be guaranteed against any accidents.
So, when working with electric current, we will adhere to the following rules:
1. Installation of motors and switching devices must be carried out by specialist installers.
2. The current in the wires must be turned off when working with them.
3. Wipe your hands dry before work, and if you work in a damp room, be sure to wear rubber galoshes on your feet and rubber gloves on your hands.
4. Carefully insulate all connections with rubber tape and ensure that the wires do not touch any walls or beams.
5. When making connections, where possible, solder the wires without using acid.
6. During experiments and wiring, turn on the current only using switches.
7. If you use current from the city network for your experiments, then never turn on the current directly to your devices from the plug, but always turn on the current in series with your devices. electric lamp. This will prevent a short circuit if the device malfunctions.
8. For all experiments with current, be sure to use two-pole fuses.
Motor guard. Although the electric motor poses the least danger of all engines, it is nevertheless necessary to protect it. Despite the fact that all motors are produced with closed casings, if they are installed on the floor, it is necessary to install a barrier around them so that children cannot reach them. Of course, if the motors are installed on walls, on brackets and high enough, then no safety devices should be made near them.
When the motor is thoroughly enclosed, the associated transmission or machinery must be fenced off. To prevent inexperienced members of the circle from aimlessly turning on the current and putting the mechanisms into action, the fuse box must be placed in an accessible place and, upon completion of work, remove the fuses so that the switch
The current could not be turned on to the motor. For the same purpose, the switch can be locked and the key kept by the manager.
In the case where the machines are powered by a foot drive, after completion of work, the transmission belts should be removed from them and locked in a cabinet.
Guarding of transmission mechanisms. Pulleys, transmissions rotating at high speed and the transmission belts driving them pose a great danger. In this case, danger threatens us from two sides. Firstly, the belt can pull clothing or a hand into the gap between itself and the pulley, and secondly, sometimes it happens that the belt breaks during operation, winds up on the operating shaft and begins to hit it in the plane of rotation. The writer of these lines himself witnessed how a broken belt from a large machine at a steam mill got entangled in the machine pulley and began to beat with such force that it destroyed the stone wall of the engine room. True, an accident with our engines cannot lead to such serious consequences, but at high rotation speeds, a broken belt can cause a lot of trouble. Therefore, both pulleys and transmission belts must be covered on all sides with wooden cases. Of course, these guards must be removable so that you can approach the transmission at any time for lubrication of bearings and routine repairs.
Sanitary rules. Almost every processing of the material is accompanied by the release of greater or lesser amounts of dust, which poses a serious danger to the eyes and lungs of a still fragile organism. Therefore, it is necessary that the room where the work is carried out is well lit and easily ventilated. To do this, the windows must be equipped with vents or transoms, and even better - electric exhaust fans.
This requirement must be met especially when working with a jigsaw. Despite the fact that this tool has a large number of positive qualities, it also has negative ones. Here, firstly, it is necessary to include the slowness of work and then harmful conditions, namely: a sitting position, and even with the body tilted towards the parts being cut, at an early age has a harmful effect on the development of the spinal column. Secondly, fine dust blown from an object spreads through the air, enters the lungs, where it settles. Thirdly, staring closely at the figured line along which the file is moving tires the eyes during long work and is the cause of the development of early farsightedness. Therefore, while paying tribute to the positive qualities of a jigsaw, one cannot ignore this aspect of working with it and recommend a passion for this tool. This work can be allowed for short periods of time and must necessarily end with light gymnastics for outdoors. The room where such work is carried out must be spacious, easily ventilated and well lit. Long-term work under artificial light is not recommended at all.

Appendix 2
LABORATORY CLUB

1. Premises. For the work of the circle, it is desirable to have a separate room of about 100 m2 where, in addition to making instruments, one could give lectures, make reports, demonstrate and conduct laboratory classes. The room should be dry and well lit natural light. It is advisable that it does not come into contact with classrooms, as the inevitable knocking and noise during operation will disturb classroom activities. To conduct light experiments and demonstrations with a projection lantern, the room must be equipped with blackout from thick double curtains and, in addition, for ventilation it is necessary to have transoms in the windows, or even better, an electric fan.
2. Desks and workplace. Tables for mounting instruments should be heavy, with thick lids, with protruding edges so that small bench vices and sawing tables for a jigsaw can be attached to them. Tables must be double: 200 cm X 75 cm, with two drawers.
3. Installation tools must be mounted on panels with sockets. These shields (Fig. 20) are equipped with two vertical strips, with the help of which they are installed at work tables.
4. For woodworking, you must have at least one medium-sized regular type workbench with two wooden clamping screws.
5. For filing, cutting and chopping metal, you should place a vice on a special bench.
6. Soldering table can be equipped electric soldering irons by the circle members themselves.
7. Since when testing instruments and during reports and lectures it is often necessary to use electric current, it is necessary to install a distribution board, which can be built by members of the circle. Current from the shield must be supplied to each workbench.
8. In addition to work tables, for demonstrations and lectures it is necessary to install a large demonstration table 100 cm high with tightly closed (front and two side) walls. The table should be equipped with drawers and shelves for storing regular utensils. Current must be supplied to the table, and if there is a gas pipeline and water supply in the school premises, then gas and water.
9. The laboratory must be equipped with a sufficiently strong projection lamp. If the circle does not have the opportunity to purchase a factory device, it can be built on its own.
10. For lectures and reports, a black board for writing with chalk and a lifting bar should be hung behind the demonstration table. White screen for demonstrations.
11. A sufficient number of cabinets must be provided to store physical instruments, tools and materials. Instrument cabinets in the upper part should be glazed, and the lower, blind part can be used for storing tools and materials.
In addition to this mandatory equipment for the normal operation of the circle, it is advisable to have in the laboratory:
12. Metal lathe.
13" Drilling machine.
The approximate location of laboratory equipment is shown in the attached diagram (Fig. 21).

Appendix 3
LIST OF BASIC PHYSICAL AND MEASURING INSTRUMENTS

1. Vernier caliper.
2. Micrometer.
3. Meter ruler.
4. Set of beakers.
5. Pycnometers.
6. Technical scales with a set of weights.
7. Chemical scales.
8. Set of hydrometers.
9. Clock.
10. Stopwatch.
11. Revolution counter.
12. Mercury barometer.
13. Aneroid barometer.
14. Psychrometer.
15. Pressure gauges for determining pressures higher and lower than one atmosphere.
16. Set of thermometers.
17. Kolbe electrometers.
18. Ammeters for direct current.
19. Ammeters for alternating current.
20. Voltmeter for direct current.
21. Voltmeter for alternating current.
22. Milliammeters.
23. Millivoltmeters.
24. Resistance standards.
25. Set of rheostats.
26. Mirror galvanometer.
27. Siren of Cagnard-Latour with furs.
28. A set of tuning forks.
29. Oily air pump with a motor.
30. Umformer for obtaining direct current.
31. Transformer.
32. Battery.
33. Projection lamp.
34. Microscope.
35. Photographic apparatus.
36. Electrophore machine.
37. Spectroscope.
38. Ruhmkorff spiral with a set of Heusler, Crookes and X-ray tubes.
39. Platinum blue screen.
40. Equilateral glass prisms (60°).
41. Large reversible prism (45°).
42. Neon lamp.

Appendix 4
LIST OF TOOLS REQUIRED FOR CONSTRUCTION OF PHYSICAL INSTRUMENTS

A jigsaw is a wooden or metal U-shaped frame, at the ends of which iron or steel clamps are attached to secure the files (in Fig. 22 the file is shown through a magnifying glass).
Usually in cheap jigsaws these clamps are tightly attached to the frame, but sometimes they are made retractable - either one upper clamp, or both.
In the first case, the clamp is attached to a vertical screw and passed through a hole in the upper end of the frame, where it is attached
the clamp (Fig. 23) is attached to a long screw; the latter is passed through a hole in the lower end of the frame, inside a wooden handle, and there is grabbed by a metal nut connected to a regulator, with which you can change the distance between the clamps. Jigsaws with such a device are somewhat more expensive, but due to the fact that they allow you to use broken files, they quickly make up for the difference in price.
The distance between the clamps on commercial jigsaws is more or less standard, but as for the frame itself, there is a wide variety: there are jigsaws whose depth does not exceed 10 mm - such tools are intended for small watchmaking and jewelry work, and jigsaws with half-meter frames , used for inlay work in furniture production.
For a physicist, extremes are not needed, and therefore it is better to buy a medium-sized jigsaw.
When purchasing, you should pay attention to the fact that the clamps fit well together, and that the clamping screws have a deep and clean cut. It often happens that
artisans who make jigsaws make poor cuts, and if the material used is soft iron, then such screws break off very quickly and the jigsaw becomes unusable.
The disadvantages of jigsaws also include weak frames that bend easily when the saws are pulled, which leads to weak tension and frequent breakdown files; Therefore, when buying a jigsaw, you should pay attention to this side.
For successful work with a jigsaw, I think it is necessary to tell the main techniques for handling this tool;
1. Do not press on the file.
2. Keep it strictly vertical without tilting.
3. If possible, avoid frame rotation.
4. Make movements of the jigsaw by rhythmically flexing and extending the right arm at the elbow joint.
5. Feed material only at those moments when the saw goes up.
6. On sharp turns it is necessary to slow down the supply of materials so that
the file moved almost in one place until the cut was sufficient
nom for turning.
7. Very sharp corners never pierce plywood or other material with an awl or drill, but when you reach a corner, go back half a centimeter, make a smooth turn and continue sawing further, and when this part falls out, then on the other side go with the saw to the top of the sharp corner.
8. Thin parts that can easily break during operation should be sawed out at the narrowest point of the cutout of the sawing clamp.
9. When the internal cutting is completed, the external contour is cut out.
10. Do not rush in your work under any circumstances.
One more note: the file is inserted into the lower clamp with its teeth downwards (Fig. 22 under the magnifying glass), and then it is passed through the hole in the material, stretched and secured in the upper clamp.
We put this tool first because when modeling it is an absolutely indispensable tool.
Anyone who takes this instrument in hand for the first time already within the first hour of work masters the “secret” of the first techniques and through short term receives into his hands the thing he has made.
But this is not the only reason for the popularity of the jigsaw with a file - it lies in its versatility. With the help of a jigsaw, we can process not only flat figures and simple models, but with a certain skill we can obtain embossed things, even partially replacing them lathe. As skills develop, the master gradually moves from a light material - wood - to a more difficult to process material, such as: celluloid, fiber, rubber, gramophone records, and from metals: aluminum, zinc, brass, iron and, finally, red copper (the most difficult material).
As you can see, not only the nature of the working methods, but also the types of material being processed and their diversity make the jigsaw a truly universal tool.
Sawing table. It is a wooden platform with a triangular cutout (Fig. 24), equipped with a clamp for attaching the table to the table. The best sawing tables are made from beech wood with the same clamping screw.
Bow saw. In our work, we cannot use only a jigsaw to cut wood, of course. Thick boards for straight
sawing will require a bow saw (Fig. 25). Bow saw blade various forms and notches exist
so many. For us, the best would be the so-called “small tooth” with a frame no more than 60 cm.
Plane. A plane is used to process the surfaces of the boards (Fig. 26).
When modeling, the best planer is one made entirely of metal with a set screw that allows you to change the angle of the blade to the surface being processed.
Flat chisel. To knock out recesses or rectangular holes in wood, we need a flat chisel (Fig. 27). So
Just like the previous tools, it should not be taken with a wide blade - it is quite enough if its width is 1 cm.
For speed of work, and mainly for its cleanliness, it is necessary that the saw, plane and chisel are always in good working order: the saw teeth are sharpened and set apart, the blades of the plane and chisel should not have jagged edges and should also be sharpened. When sharpening blades, care should be taken to ensure that the chamfer of the blade has a completely flat surface and does not protrude into a hump.
Kleyanka. To connect wooden parts in our work, we often use wood glue. The glue does not lose its binding properties only if it does not burn during cooking. In order to avoid this, you should build a special tank for cooking it. It can be made from two tin cans - one larger and the other smaller. To the top
A ring of tin is soldered to the edge of the smaller can so that the inner can does not fall through and so that there is a small gap between the bottoms of the cans (Fig. 28).
The glue (the best one is transparent) is crushed with a hammer, placed in an inner jar and filled with water for a day. As a result, it swells, increases in volume, and its edges become semi-liquid. Before cooking, excess water is drained, clean water is poured into the gap between the jars, the glue is placed on the fire, and when the water boils, the glue will begin to dissolve in the water bath. Cooking should be continued until Fig. 28 the adhesive mass will not become homogeneous and slightly viscous; then the glue is ready for use. It should be consumed hot, and so that it does not cool down during operation, it must be kept on low heat.
Vise. A vice is used to strengthen the material being processed. They come in “canteen” types, tightly attached to carpenter's workbench, and a small “removable” vice with a clamp (Fig. 29 and 30). For our work, the latter are more convenient. There are two types of vices for the clamping device: most often you come across vices in which the lips clamping the material move at a certain angle to each other, while in the best vices the lips move parallel to each other, which is why these vices are called parallel vices. The latter are much more convenient for us in our work, and therefore if we have to buy a vice, it is better to purchase parallel ones. When purchasing, you should pay attention to the fact that their lips are made of separate pieces of steel, as well as to the cleanliness and depth of cutting of the clamping screw.
Anvil. For cutting thick plates of metal, flattening and cold forging, it is advisable to have at least a small piece of rail or I-beam.
Files. Due to the fact that our work will be quite varied, we should acquire several files of various medium-sized sections.
The most suitable sections for us will be flat, triangular, semicircular and round (Fig. 31). Mechanics divide files or, as they call them, "hand saws" into two categories: "fighter" saws and "personal" saws. They differ in the size of the notch - the first ones have a coarser notch and are used for
more rough primary metal processing. Due to the nature of our work, the need for them will be small, and if they are not at our disposal, we can easily do without them - with only personal saws.
For small jobs, so-called velvet saws with a very fine cut, almost invisible to the eye, can be of great benefit to us.
Finally, when modeling you cannot do without needle files - very small files of the same profiles.
Plumber's scissors. For cutting sheet metal Pruning shears are used. When purchasing them, you should pay attention to a good and tight fit of the knives (Fig. 32).
When working with scissors, you should clamp one handle in a vice, feed the material with your left hand, and act on the upper handle of the scissors with your right hand.
Hacksaw. To cut thick pieces of metal, use a hacksaw, which is a fine-toothed saw. 32 PI/1U made of hardened steel, tensioned into a metal frame. Frames come in two types - permanent with a constant distance between the clamps and hinged. The latter are more convenient, as they allow you to use canvases of various lengths and even fragments of canvases.
Chisel. This tool is used for chopping metal and is a rod with a flat blade (Fig. 33).
Since we don’t have to chop large surfaces, a chisel with a 1 cm blade is quite enough for us. If we can’t get one on the market, then we can order it from any blacksmith.
Kern. A core is used to mark the places on the metal that need to be drilled. It is a steel cylinder with one end sharpened to a cone. It can also be ordered from a blacksmith.
Bench drill. For drilling holes in metal (and other materials), the most convenient tool is a table drill, which is a small drilling machine, attached to a table and driven by a small handle connected to a pair of bevel gears.
Hand drill. For drilling small holes in both metal and wood, a good tool is a drill, which is a screw with a very sharp round thread (Fig. 34). The upper end of this screw rotates in a wooden head that serves as a handle, and a feather clip is attached to the lower end. A nut slides along the screw, which sets the drill in motion. The best drills are two-way drills, in which the nut sets the drill in motion both when lowering it down and when lifting it up. Drills with a balancer are also good for drilling small holes - their nut is arranged in such a way that the upward stroke is idle, and the drill continues to rotate by inertia in the working direction (clockwise).
When purchasing a drill, you should pay attention to the softness of the screw in the head and the cutting of the clamping nut - the cutting should be clean and deep.
For drilling in wood, punches are used, which are steel rods with a rhombic extension at the working end (Fig. 35).
Drills for metal are often made of the same shape, but they are made from harder and more hardened steel, and therefore, due to their fragility, they should not be used for drilling wood, since they break easily in viscous material. For drilling metal, it is better to use screw twist drills (Fig. 36), made from the highest grades of steel.
When drilling soft metals such as red copper, aluminum, lead, zinc and soft iron, it is necessary to 35. Fig. 36 It is important to pour oil over the drilling area, or at least kerosene, otherwise metal shavings will wrap around the drill, which will easily break as a result. "
Screw-cutting board. It is a steel plate with cut holes for screws of various sections and then hardened. Usually, for the same size, two cuts are made in the board - one for the first pass through the screw, and a second slightly smaller one for the final cutting of the screw.
In order not to spoil the tool and get a good screw, the following conditions must be observed when cutting: the rod on which the cutting is made must be slightly larger than the hole, and its end must be slightly lowered onto the cone so that the threaded nut grips the metal. The rod to be cut is fixed as low as possible in a vice, a screw-cutting board with the corresponding number is put on it and turned with gentle pressure down clockwise. If the diameter of the rod corresponds to the hole in the board, then the latter, cutting off the metal, rotates relatively easily on the rod, gradually lowering down. If the board “sticks,” this means that the diameter of the rod is large, and the following can happen: either the cutting in the board breaks and the board is damaged, or the rod breaks, twisting around its axis; some of it will get stuck in the board. You will have to subsequently drill it out from there, and this operation can ruin the cutting in the board. To prevent the rod from breaking, you should immediately unscrew the board from the rod and then saw it in a vice to the required diameter and try to cut the screw. If this time the board works, then you need to drop a drop of oil on the cutting hole and start cutting. If the screw is long, then, having reached the vice, you should raise the rod slightly and continue cutting until the entire screw is threaded. Then screw the board and go through the entire screw again with the next, slightly smaller hole in the board of the same number. When the board goes through the entire screw from top to bottom and back, the cutting will be ready.
To cut the corresponding nuts, a set of taps of the same numbers is attached to each screw-cutting board. When purchasing, you should pay attention to the taps so that the cuts on them are deep, clean and sharp.
Pliers, round nose pliers and wire cutters. To work with metal, the following tools are required. Their very name indicates that the clamping lips of the first tool (Fig. 37) are flat surfaces, those of the second (Fig. 38) are round, and those of the third are sharp (Fig. 39) for biting nails and wires.
When purchasing them, you should pay attention to the cleanliness of the finish, and mainly to the precise fit of the working parts of the tools.
Soldering iron. To connect individual metal parts, a soldering iron is required (Fig. 40). Soldering irons differ in their purpose for soldering the surface (a) and internal parts of a vessel (£). They then vary in weight. A soldering iron weighing 100 - 200 g will be quite sufficient for us.
When working with a soldering iron, we remind inexperienced craftsmen that the heel of the soldering iron should be heated, not the toe.
Needless to say, in our school practice the most convenient soldering iron is an electric one. If you have an electric iron at your disposal and if you cannot purchase a factory soldering iron, then you need to build it yourself.
Screwdriver. For clean work, it is desirable that its dimensions exactly match the screw head.
Hammer. For all work on wood and metal, this tool is necessary. It is best to have a plumber's hammer with a flat heel and a sharp point on the other side. Its weight of 500 g will be quite sufficient for us.
Finally, during installation work we cannot do without such household tools as scissors for paintings and paper, thin sheet metal, and a straight awl with a rhombic cross-section. When working with cardboard, we will really need a so-called bookbinding knife.

Appendix 5
HOUSEHOLD MATERIALS IN THE PHYSICS CLUB

We do not present here full list materials for a physical circle - it is too large, and we will limit ourselves to indicating materials found in household use and suitable for use in the work of a physical circle.
Aluminum cookware(mugs, pots, pans) - valuable material when building models.
Glass jars (preferably pharmaceutical jars, smooth, of different sizes) are used in almost all departments of physics.
Newsprint paper, for making papier-mâché, tissue paper, colored paper for electrostatics, binding paper for pasting many devices.
Bottles of different sizes for making glasses, cylinders, etc.
Wax, paraffin for filling devices; for impregnation of wooden planks, to give them some insulating properties and for matte polishing of wooden parts of devices.
Nuts of different sizes are used as weights for experiments in mechanics, as samples of metals when determining heat capacity.
Copper shells from rifle cartridges of various calibers are an extremely valuable material, which, in the absence of copper tubes, can be used in all departments of physics.
Gramophone records. The plates are easily softened on a hot but not hot stove, cut with scissors, rolled into tubes, bent, the seams are melted on the flame of an alcohol burner and easily sealed. When cold, they can be easily filed with a jigsaw, files, sanded and polished.
Graphite (pencils) has electrical applications as a high-resistivity material. Crushed to a powder, it is used as a dry lubricant for rubbing parts made of wood.
Dermantin for gluing devices.
Fraction as a container for casting material.
Iron wire (furnace and from packing boxes). It is used in all departments of physics.
Tin (boxes and cans) is used in all departments of physics.
Mirrors (fragments); light, electricity.
Gear wheels (from broken watches, gramophones and wind-up children's toys) are used mainly in mechanics in the construction of technical models and in some other departments of physics; for example, in electricity they can be used as breakers.
Cardboard (boxes, old bindings) - in all departments of physics.
Reels (wooden from threads and iron from typewriter ribbons): in mechanics and in electrical modeling.
Electric light bulbs. The bases are used to make cartridges and plugs, and glass containers are used in the gas department; filled with water, can be used as light condensers.
Safety razor blades: magnetism, electricity, light.
Glass lenses (broken children's toys, scattered instruments and magnifying glasses): light.
Coins (silver, nickel, copper and aluminum bronze). The former are like material, and the latter are like gram weight - a penny weighs a gram, etc., and five kopecks weighs five grams.
Metal filings: magnetism and electricity.
Lead fillings are used as a material for castings.
Sunflower pulp. Dried, it is easily cut with a sharp razor and replaces elderberry pith, which is not available everywhere, for experiments in electrostatics.
Glass prisms (lamp pendants): light.
Test tubes (as vessels for storing various medications and photochemicals) are used in many departments of physics.
Cortical traffic jams occur in almost all departments of physics.
Insulated wire of various sections (damaged bells, physical devices, etc.) - in the electricity department.
Steel springs (from broken watches, gramophones and children's toys) - in mechanics, electricity, sound and modeling.
Bullets (mainly military grade) - in many departments of physics.
Lead scrap - as a material for casting.
Mica: light and electricity.
Steel needles (sewing and knitting) - in magnetism, electricity and modeling.
Sheet glass (damaged negatives and window glass): optics, hydrostatics, electricity.
Iron and steel strings: sound, modeling.
Sealing wax: gases, liquids, electricity.
Spectacle glasses (concave and convex) are an excellent material for optical instruments and technical models.
Charcoal sticks (from arc lights and pocket batteries): electricity.
Plywood: all departments of physics and modeling.
Fiber is an excellent insulating material.
Faceted bottles (from perfume and cologne): for storing chemical reagents and as material for the construction of some devices around the world.
Cellophane (packaging material) - has birefringent properties.
Celluloid (films and photographic films). If we remove the emulsion, we get a good, unbreakable, transparent material for protecting the scales of measuring instruments. Dissolve in acetone or pear essence to obtain celluloid glue. Important note: never forget that films and everything derived from them are highly flammable.
Zinc (boxes, electrodes from elements) - in many departments of physics and as a material for castings.
Clock circuits: mechanics, electricity and modeling.
Silk threads and fabric: electricity.
Boxes (packaging) - as material for all departments of physics.

Fomin Daniil

Physics is an experimental science and creating instruments with your own hands contributes to a better understanding of laws and phenomena. Many different questions arise when studying each topic. Many can be answered by the teacher himself, but how wonderful it is to get the answers through your own independent research.

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DISTRICT RESEARCH CONFERENCE OF STUDENTS

SECTION “Physics”

Project

Do-it-yourself physical device.

8th grade student

GBOU secondary school No. 1 town. Sukhodol

Sergievsky district, Samara region

Scientific supervisor: Shamova Tatyana Nikolaevna

Physics teacher

1. Introduction.

1. Main part.

1. Purpose of the device;
2. tools and materials;
3. Manufacturing of the device;
4. General view of the device;
5. Features of the device demonstration.

3.Research.

4. Conclusion.

5. List of used literature.

1. Introduction.

In order to provide the necessary experience, you need to have instruments and measuring instruments. And don’t think that all devices are made in factories. In many cases, research facilities are built by the researchers themselves. At the same time, it is believed that the more talented researcher is the one who can carry out experiments and obtain good results not only on complex, but also on simpler instruments. It is reasonable to use complex equipment only in cases where it is impossible to do without it. So don’t neglect homemade devices; it’s much more useful to make them yourself than to use store-bought ones.

TARGET:

Make a device, a physics installation to demonstrate physical phenomena with your own hands.

Explain the operating principle of this device. Demonstrate the operation of this device.

TASKS:

Make devices that arouse great interest among students.

Make devices that are not available in the laboratory.

Make devices that cause difficulty in understanding theoretical material in physics.

Investigate the dependence of the period on the length of the thread and the amplitude of the deflection.

HYPOTHESIS:

Use the made device, a physics installation for demonstrating physical phenomena with your own hands in the lesson.

If this device is not available in the physical laboratory, this device will be able to replace the missing installation when demonstrating and explaining the topic.

2. Main part.

2.1. Purpose of the device.

The device is designed to observe resonance in mechanical vibrations.

2.2.Tools and materials.

Ordinary wire, balls, nuts, tin, fishing line. Soldering iron.

2.3. Manufacturing of the device.

Bend the wire into a support. Stretch the common line. Solder the balls to the nuts, measure 2 pieces of fishing line of the same length, the rest should be shorter and longer by several centimeters, hang the balls with them. Make sure that pendulums with the same length of fishing line are not located next to each other. The device is ready for experiment!

2.4. General view of the device.

2.5.Features of the device demonstration.

To demonstrate the device, it is necessary to select a pendulum whose length coincides with the length of one of the three remaining ones; if you deviate the pendulum from the equilibrium position and leave it to itself, then it will perform free oscillations. This will cause the fishing line to oscillate, as a result of which a driving force will act on the pendulums through the suspension points, periodically changing in magnitude and direction with the same frequency as the pendulum oscillates. We will see that a pendulum with the same length of suspension will begin to oscillate with the same frequency, while the amplitude of oscillations of this pendulum is much greater than the amplitudes of other pendulums. In this case, the pendulum oscillates in resonance with pendulum 3. This happens because the amplitude of steady-state oscillations caused by the driving force reaches its greatest value precisely when the frequency of the changing force coincides with the natural frequency of the oscillatory system. The fact is that in this case the direction of the driving force at any moment of time coincides with the direction of movement of the oscillating body. In this way, the most favorable conditions are created for replenishing the energy of the oscillatory system due to the work of the driving force. For example, in order to swing a swing more strongly, we push it in such a way that the direction of the acting force coincides with the direction of movement of the swing. But it should be remembered that the concept of resonance is applicable only to forced oscillations.

3. Thread or mathematical pendulum

Hesitation! Our gaze falls on the pendulum of the wall clock. He rushes restlessly, first in one direction, then in the other, with his blows as if breaking the flow of time into precisely measured segments. “One-two, one-two,” we involuntarily repeat in time with his ticking.

A plumb line and a pendulum are the simplest of all instruments used in science. It is all the more surprising that truly fabulous results have been achieved with such primitive tools: thanks to them, man has managed to penetrate mentally into the bowels of the Earth, to find out what is happening tens of kilometers under our feet.

Swinging to the left and back to the right, to the original position, constitutes a complete swing of the pendulum, and the time of one complete swing is called the period of swing. The number of times a body oscillates per second is called the oscillation frequency. A pendulum is a body suspended on a thread, the other end of which is fixed. If the length of the thread is large compared to the size of the body suspended on it, and the mass of the thread is negligible compared to the mass of the body, then such a pendulum is called a mathematical or thread pendulum. Almost a small heavy ball suspended on a light long thread can be considered a thread pendulum.

The period of oscillation of a pendulum is expressed by the formula:

Т = 2π √ l/g

From the formula it is clear that the period of oscillation of the pendulum does not depend on the mass of the load or the amplitude of the oscillations, which is especially surprising. After all, with different amplitudes, an oscillating body travels different paths during one oscillation, but the time spent on it is always the same. The duration of a pendulum's swing depends on its length and the acceleration of gravity.

In our work, we decided to test experimentally that the period does not depend on other factors and verify the validity of this formula.

Study of the dependence of the oscillations of a pendulum on the mass of the oscillating body, the length of the thread and the magnitude of the initial deflection of the pendulum.

Study.

Devices and materials: stopwatch, measuring tape.

We first measured the period of oscillation of the pendulum for a body mass of 10 g and a deflection angle of 20°, while changing the length of the thread.

The period was also measured by increasing the deflection angle to 40°, with a mass of 10 g and different lengths of the thread. The measurement results were entered into a table.

Table.

From experiments we were convinced that the period really does not depend on the mass of the pendulum and its angle of deflection, but with increasing length of the pendulum thread, the period of its oscillation will increase, but not in proportion to the length, but in a more complex manner. The experimental results are shown in the table.

So, the period of oscillation of a mathematical pendulum depends only on the length of the pendulum l and from the acceleration of free fall g.

4. Conclusion.

It is interesting to observe the experiment conducted by the teacher. Carrying it out yourself is doubly interesting.

And conducting an experiment with a device made and designed with your own hands arouses great interest among the whole class. INIn such experiments it is easy to establish a relationship and draw a conclusion about how this installation works.

5.Literature.

1. Teaching equipment for physics in high school. Edited by A.A. Pokrovsky “Enlightenment” 1973

2. Textbook on physics by A. V. Peryshkina, E. M. Gutnik “Physics” for grade 9;

3. Physics: Reference materials: O.F. Kabardin Textbook for students. – 3rd ed. – M.: Education, 1991.

Do you love physics? You love experiment? The world of physics is waiting for you!
What could be more interesting than experiments in physics? And, of course, the simpler the better!
These exciting experiments will help you see extraordinary phenomena light and sound, electricity and magnetism Everything necessary for the experiments is easy to find at home, and the experiments themselves simple and safe.
Your eyes are burning, your hands are itching!
Go ahead, explorers!

Robert Wood - a genius of experimentation.........
- Up or down? Rotating chain. Fingers of salt......... - The Moon and diffraction. What color is the fog? Newton's rings......... - A top in front of the TV. Magic propeller. Ping-pong in the bath......... - Spherical aquarium - lens. Artificial mirage. Soap glasses......... - Eternal salt fountain. Fountain in a test tube. Rotating spiral......... - Condensation in a jar. Where is the water vapor? Water engine........ - Popping egg. An overturned glass. Swirl in a cup. Heavy newspaper.........
- IO-IO toy. Salt pendulum. Paper dancers. Electric dance.........
- The mystery of ice cream. Which water will freeze faster? It's frosty, but the ice is melting! .......... - Let's make a rainbow. A mirror that doesn't confuse. Microscope made from a drop of water.........
- The snow creaks. What will happen to the icicles? Snow flowers......... - Interaction of sinking objects. Ball is touchable.........
- Who is faster? Reactive balloon. Air carousel......... - Bubbles from a funnel. Green hedgehog. Without opening the bottles......... - Spark plug motor. Bump or hole? A moving rocket. Divergent rings.........
- Multi-colored balls. Sea resident. Balancing egg.........
- Electric motor in 10 seconds. Gramophone..........
- Boil, cool......... - Waltzing dolls. Flame on paper. Robinson's feather.........
- Faraday experiment. Segner wheel. Nutcrackers......... - Dancer in the mirror. Silver plated egg. Trick with matches......... - Oersted's experience. Roller coaster. Don't drop it! ..........

Body weight. Weightlessness.
Experiments with weightlessness. Weightless water. How to reduce your weight.........

Elastic force
- Jumping grasshopper. Jumping ring. Elastic coins..........
Friction
- Reel-crawler..........
- Drowned thimble. Obedient ball. We measure friction. Funny monkey. Vortex rings.........
- Rolling and sliding. Rest friction. The acrobat is doing a cartwheel. Brake in the egg.........
Inertia and inertia
- Take out the coin. Experiments with bricks. Wardrobe experience. Experience with matches. Inertia of the coin. Hammer experience. Circus experience with a jar. Experiment with a ball.........
- Experiments with checkers. Domino experience. Experiment with an egg. Ball in a glass. Mysterious skating rink.........
- Experiments with coins. Water hammer. Outsmarting inertia.........
- Experience with boxes. Experience with checkers. Coin experience. Catapult. Inertia of an apple.........
- Experiments with rotational inertia. Experiment with a ball.........

Mechanics. Laws of mechanics
- Newton's first law. Newton's third law. Action and reaction. Law of conservation of momentum. Quantity of movement.........

Jet propulsion
- Jet shower. Experiments with jet spinners: air spinner, jet balloon, ether spinner, Segner wheel.........
- Balloon rocket. Multistage rocket. Pulse ship. Jet boat.........

Free fall
-Which is faster.........

Circular movement
- Centrifugal force. Easier on turns. Experience with the ring.........

Rotation
- Gyroscopic toys. Clark's top. Greig's top. Lopatin's flying top. Gyroscopic machine.........
- Gyroscopes and tops. Experiments with a gyroscope. Experience with a top. Wheel experience. Coin experience. Riding a bike without hands. Boomerang experience.........
- Experiments with invisible axes. Experience with paper clips. Rotating a matchbox. Slalom on paper.........
- Rotation changes shape. Cool or damp. Dancing egg. How to put a match.........
- When the water does not pour out. A bit of a circus. Experiment with a coin and a ball. When the water pours out. Umbrella and separator..........

Statics. Equilibrium. Center of gravity
- Vanka-stand up. Mysterious nesting doll.........
- Center of gravity. Equilibrium. Center of gravity height and mechanical stability. Base area and balance. Obedient and naughty egg..........
- Center of gravity of a person. Balance of forks. Fun swing. A diligent sawyer. Sparrow on a branch.........
- Center of gravity. Pencil competition. Experience with unstable balance. Human balance. Stable pencil. Knife at the top. Experience with a ladle. Experience with a saucepan lid.........

Structure of matter
- Fluid model. What gases does air consist of? Highest density of water. Density tower. Four floors.........
- Plasticity of ice. A nut that has come out. Properties of non-Newtonian fluid. Growing crystals. Properties of water and eggshells..........

Thermal expansion
- Expansion of a solid. Lapped plugs. Needle extension. Thermal scales. Separating glasses. Rusty screw. The board is in pieces. Ball expansion. Coin expansion.........
- Expansion of gas and liquid. Heating the air. Sounding coin. Water pipe and mushrooms. Heating water. Warming up the snow. Dry from the water. The glass is creeping.........

Surface tension of a liquid. Wetting
- Plateau experience. Darling's experience. Wetting and non-wetting. Floating razor.........
- Attraction of traffic jams. Sticking to water. A miniature Plateau experience. Bubble..........
- Live fish. Paperclip experience. Experiments with detergents. Colored streams. Rotating spiral.........

Capillary phenomena
- Experience with a blotter. Experiment with pipettes. Experience with matches. Capillary pump.........

Bubble
- Hydrogen soap bubbles. Scientific preparation. Bubble in a jar. Colored rings. Two in one..........

Energy
- Transformation of energy. Bent strip and ball. Tongs and sugar. Photo exposure meter and photo effect.........
- Translation mechanical energy to thermal. Propeller experience. Bogatyr in a thimble..........

Thermal conductivity
- Experiment with an iron nail. Experience with wood. Experience with glass. Experiment with spoons. Coin experience. Thermal conductivity of porous bodies. Thermal conductivity of gas.........

Heat
-Which is colder. Heating without fire. Absorption of heat. Radiation of heat. Evaporative cooling. Experiment with an extinguished candle. Experiments with the outer part of the flame..........

Radiation. Energy transfer
- Transfer of energy by radiation. Experiments with solar energy.........

Convection
- Weight is a heat regulator. Experience with stearin. Creating traction. Experience with scales. Experience with a turntable. Pinwheel on a pin..........

Aggregate states.
- Experiments with soap bubbles in the cold. Crystallization
- Frost on the thermometer. Evaporation from the iron. We regulate the boiling process. Instant crystallization. growing crystals. Making ice. Cutting ice. Rain in the kitchen.........
- Water freezes water. Ice castings. We create a cloud. Let's make a cloud. We boil the snow. Ice bait. How to get hot ice.........
- Growing crystals. Salt crystals. Golden crystals. Large and small. Peligo's experience. Experience-focus. Metal crystals.........
- Growing crystals. Copper crystals. Fairytale beads. Halite patterns. Homemade frost.........
- Paper pan. Dry ice experiment. Experience with socks.........

Gas laws
- Experience on the Boyle-Mariotte law. Experiment on Charles's law. Let's check the Clayperon equation. Let's check Gay-Lusac's law. Ball trick. Once again about the Boyle-Mariotte law..........

Engines
- Steam engine. The experience of Claude and Bouchereau.........
- Water turbine. Steam turbine. Wind engine. Water wheel. Hydro turbine. Windmill toys.........

Pressure
- Pressure of a solid body. Punching a coin with a needle. Cutting through ice.........
- Siphon - Tantalus vase..........
- Fountains. The simplest fountain. Three fountains. Fountain in a bottle. Fountain on the table.........
- Atmosphere pressure. Bottle experience. Egg in a decanter. Can sticking. Experience with glasses. Experience with a can. Experiments with a plunger. Flattening the can. Experiment with test tubes.........
- Vacuum pump made from blotting paper. Air pressure. Instead of the Magdeburg hemispheres. A diving bell glass. Carthusian diver. Punished curiosity.........
- Experiments with coins. Experiment with an egg. Experience with a newspaper. School gum suction cup. How to empty a glass.........
- Pumps. Spray..........
- Experiments with glasses. The mysterious property of radishes. Experience with a bottle.........
- Naughty plug. What is pneumatics? Experiment with a heated glass. How to lift a glass with your palm.........
- Cold boiling water. How much does water weigh in a glass? Determine lung volume. Resistant funnel. How to pierce a balloon without it bursting..........
- Hygrometer. Hygroscope. Barometer from a cone......... - Barometer. Aneroid barometer - do it yourself. Balloon barometer. The simplest barometer......... - Barometer from a light bulb.......... - Air barometer. Water barometer. Hygrometer..........

Communicating vessels
- Experience with the painting.........

Archimedes' law. Buoyancy force. Floating bodies
- Three balls. The simplest submarine. Grape experiment. Does iron float.........
- Ship's draft. Does the egg float? Cork in a bottle. Water candlestick. Sinks or floats. Especially for drowning people. Experience with matches. Amazing egg. Does the plate sink? The mystery of the scales.........
- Float in a bottle. Obedient fish. Pipette in a bottle - Cartesian diver..........
- Ocean level. Boat on the ground. Will the fish drown? Stick scales.........
- Archimedes' Law. Live toy fish. Bottle level.........

Bernoulli's law
- Experience with a funnel. Experiment with water jet. Ball experiment. Experience with scales. Rolling cylinders. stubborn leaves.........
- Bendable sheet. Why doesn't he fall? Why does the candle go out? Why doesn't the candle go out? The air flow is to blame.........

Simple mechanisms
- Block. Pulley hoist.........
- Lever of the second type. Pulley hoist.........
- Lever arm. Gate. Lever scales.........

Oscillations
- Pendulum and bicycle. Pendulum and globe. A fun duel. Unusual pendulum..........
- Torsion pendulum. Experiments with a swinging top. Rotating pendulum.........
- Experiment with the Foucault pendulum. Addition of vibrations. Experiment with Lissajous figures. Resonance of pendulums. Hippopotamus and bird.........
- Fun swing. Oscillations and resonance.........
- Fluctuations. Forced vibrations. Resonance. Seize the moment.........

Sound
- Gramophone - do it yourself..........
- Physics of musical instruments. String. Magic bow. Ratchet. Singing glasses. Bottlephone. From bottle to organ.........
- Doppler effect. Sound lens. Chladni's experiments.........
- Sound waves. Propagation of sound.........
- Sounding glass. Flute made from straw. The sound of a string. Reflection of sound.........
- Phone made from a matchbox. Telephone exchange.........
- Singing combs. Spoon ringing. Singing glass.........
- Singing water. Shy wire.........
- Sound oscilloscope..........
- Ancient sound recording. Cosmic voices.........
- Hear the heartbeat. Glasses for ears. Shock wave or firecracker..........
- Sing with me. Resonance. Sound through the bone.........
- Tuning fork. A storm in a teacup. Louder sound.........
- My strings. Changing the pitch of the sound. Ding Ding. Crystal clear.........
- We make the ball squeak. Kazoo. Singing bottles. Choral singing..........
- Intercom. Gong. Crowing glass.........
- Let's blow out the sound. Stringed instrument. Small hole. Blues on bagpipes..........
- Sounds of nature. Singing straw. Maestro, march.........
- A speck of sound. What's in the bag? Sound on the surface. Day of disobedience.........
- Sound waves. Visual sound. Sound helps you see.........

Electrostatics
- Electrification. Electric panty. Electricity is repellent. Dance of soap bubbles. Electricity on combs. The needle is a lightning rod. Electrification of the thread.........
- Bouncing balls. Interaction of charges. Sticky ball.........
- Experience with a neon light bulb. Flying bird. Flying butterfly. An animated world.........
- Electric spoon. St. Elmo's Fire. Electrification of water. Flying cotton wool. Electrification of a soap bubble. Loaded frying pan.........
- Electrification of the flower. Experiments on human electrification. Lightning on the table.........
- Electroscope. Electric Theater. Electric cat. Electricity attracts.........
- Electroscope. Bubble. Fruit battery. Fighting gravity. Battery galvanic cells. Connect the coils.........
- Turn the arrow. Balancing on the edge. Repelling nuts. Turn on the light.........
- Amazing tapes. Radio signal. Static separator. Jumping grains. Static rain.........
- Film wrapper. Magic figurines. Influence of air humidity. Revived door knob. Sparkling clothes.........
- Charging from a distance. Rolling ring. Crackling and clicking sounds. Magic wand..........
- Everything can be charged. Positive charge. Attraction of bodies. Static glue. Charged plastic. Ghost leg.........

Semyon Burdenkov and Yuri Burdenkov

Making a device with your own hands is not only a creative process that encourages you to show your ingenuity and ingenuity. In addition, during the manufacturing process, and even more so when demonstrating it in front of a class or the entire school, the manufacturer receives a lot of positive emotions. The use of homemade devices in the classroom develops a sense of responsibility and pride in the work performed and proves its significance.

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Preview:

Municipal government educational institution

Kukui basic secondary school No. 25

Project

Do-it-yourself physics device

Completed by: 8th grade student

MKOU secondary school No. 25

Burdenkov Yu.

Head: Davydova G.A.,

Physics teacher.

1. Introduction.
2. Main part.

1. Purpose of the device;
2. tools and materials;
3. Manufacturing of the device;
4. General view of the device;

1. Conclusion.
2. Bibliography.

1. Introduction.

In order to provide the necessary experience, you need to have instruments and measuring instruments. And don’t think that all devices are made in factories. In many cases, research facilities are built by the researchers themselves. At the same time, it is believed that the more talented researcher is the one who can carry out experiments and obtain good results not only on complex, but also on simpler instruments. It is reasonable to use complex equipment only in cases where it is impossible to do without it. So don’t neglect homemade devices; it’s much more useful to make them yourself than to use store-bought ones.

TARGET:

Make a device, a physics installation to demonstrate physical phenomena with your own hands.

Explain the operating principle of this device. Demonstrate the operation of this device.

TASKS:

Make devices that arouse great interest among students.

Make devices that are not available in the laboratory.

Make devices that cause difficulty in understanding theoretical material in physics.

HYPOTHESIS:

Use the made device, a physics installation for demonstrating physical phenomena with your own hands in the lesson.

If this device is not available in the physical laboratory, this device will be able to replace the missing installation when demonstrating and explaining the topic.

1. Main part.

1. Purpose of the device.

The device is designed to observe the expansion of air and liquid when heated.

1. Tools and materials.

An ordinary bottle, a rubber stopper, a glass tube, the outer diameter of which is 5-6 mm. Drill.

1. Manufacturing of the device.

Use a drill to make a hole in the cork so that the tube fits tightly into it. Next, pour colored water into the bottle to make it easier to observe. Apply a scale to the neck. Then insert the cork into the bottle so that the tube in the bottle is below the water level. The device is ready for experiment!

1. General view of the device.

1. Features of the device demonstration.

To demonstrate the device, you need to wrap your hand around the neck of the bottle and wait a while. We will see that the water begins to rise up the tube. This happens because the hand heats the air in the bottle. When heated, the air expands, puts pressure on the water and displaces it. The experiment can be done with different amounts of water, and you will see that the level of rise will be different. If the bottle is completely filled with water, you can already observe the expansion of water when heated. To verify this, you need to lower the bottle into a vessel with hot water.

1. Conclusion.

It is interesting to observe the experiment conducted by the teacher. Carrying it out yourself is doubly interesting.

And conducting an experiment with a device made and designed with your own hands arouses great interest among the whole class. In such experiments it is easy to establish a relationship and draw a conclusion about how this installation works.

1. Literature.

1. Teaching equipment for physics in high school. Edited by A.A. Pokrovsky “Enlightenment” 1973

The text of the work is posted without images and formulas.
The full version of the work is available in the "Work Files" tab in PDF format

annotation

This school year I began to study this very interesting science that is necessary for every person. From the very first lesson, physics captivated me, lit a fire in me with a desire to learn new things and get to the bottom of the truth, drew me into thought, brought me to interesting ideas...

Physics is not only scientific books and complex instruments, not only huge laboratories. Physics is also about tricks performed among friends, this is funny stories and funny homemade toys. Physical experiments can be done with a ladle, a glass, a potato, a pencil, balls, glasses, pencils, plastic bottles, coins, needles, etc. Nails and straws, matches and cans, scraps of cardboard and even drops of water - everything will go into use! (3)

Relevance: physics is an experimental science and creating instruments with your own hands contributes to a better understanding of laws and phenomena.

Many different questions arise when studying each topic. A teacher can answer many things, but how wonderful it is to get the answers through your own independent research!

Target: make physics devices to demonstrate some physical phenomena with your own hands, explain the principle of operation of each device and demonstrate their operation.

Tasks:

Study scientific and popular literature.

Learn to apply scientific knowledge to explain physical phenomena.

Make devices that arouse great interest among students.

Replenishment of the physics classroom with homemade devices made from scrap materials.

Take a deeper look at the practical use of the laws of physics.

Project product: DIY devices, videos of physical experiments.

Project result: the interest of students, the formation of their idea that physics as a science is not divorced from real life, the development of motivation for learning physics.

Research methods: analysis, observation, experiment.

The work was carried out according to the following scheme:

Formulation of the problem.

Studying information from various sources on this issue.

Selection of research methods and practical mastery of them.

Collection own material- collecting available materials, conducting experiments.

Analysis and synthesis.

Formulation of conclusions.

During the work the following were used physical research methods:

I. Physical experience

The experiment consisted of the following stages:

Clarification of the experimental conditions.

This stage involves familiarization with the conditions of the experiment, determination of the list of necessary available instruments and materials and safe conditions during the experiment.

Drawing up a sequence of actions.

At this stage, the procedure for conducting the experiment was outlined, and new materials were added if necessary.

Conducting the experiment.

Modeling is the basis of any physical research. When conducting experiments, we simulated the structure of a fountain, reproduced ancient experiments: “Tantalus’ Vase”, “Cartesian Diver”, created physical toys and instruments to demonstrate physical laws and phenomena.

In total, we modeled, conducted and scientifically explained 12 entertaining physical experiments.

MAIN PART.

Physics, translated from Greek, is the science of nature. Physics studies phenomena that occur in space, in the bowels of the earth, on the earth, and in the atmosphere - in a word, everywhere. Such common phenomena are called physical phenomena.

When observing an unfamiliar phenomenon, physicists try to understand how and why it occurs. If, for example, a phenomenon occurs quickly or occurs rarely in nature, physicists strive to see it as many times as necessary in order to identify the conditions under which it occurs and establish the corresponding patterns. If possible, scientists reproduce the phenomenon being studied in a specially equipped room - a laboratory. They try not only to examine the phenomenon, but also to make measurements. Scientists - physicists call all this experience or experiment.

Observation does not end with observation, but only the beginning of the study of a phenomenon. The facts obtained during observation must be explained using existing knowledge. This is the stage of theoretical understanding.

In order to verify the correctness of the explanation found, scientists test it experimentally. (6)

Thus, the study of a physical phenomenon usually goes through the following stages:

1. Observation

   Experiment

   Theoretical background

   Practical use

While carrying out my scientific fun at home, I developed the basic steps that allow you to conduct a successful experiment:

For home experimental assignments, I put forward the following requirements:

safety during carrying out;

minimal material costs;

ease of implementation;

value in learning and understanding physics.

I have conducted many experiments on various topics 7th grade physics course. I will present some of them, in my opinion, the most interesting and at the same time simple to implement.

2.2 Experiments and instruments on the topic “Mechanical phenomena”

Experience No. 1. « Reel - crawler»

Materials: wooden spool of thread, nail (or wooden skewer), soap, rubber band.

Sequencing

Is friction harmful or beneficial?

To understand this better, make a crawling reel toy. This is the most simple toy with rubber motor.

Let's take an ordinary old spool of thread and use a penknife to notch the edges of both its cheeks. Fold a strip of rubber 70-80 mm long in half and push it into the hole of the reel. In the elastic loop that peeks out from one end, we will place a piece of a match 15 mm long.

Place a soap washer on the other cheek of the coil. Cut a circle from hard, dry soap about 3 mm thick. The diameter of the circle is about 15 mm, the diameter of the hole in it is 3 mm. Place a new, shiny steel nail 50-60 mm long on the soap washer and tie the ends of the elastic band on top of this nail with a secure knot. Turning the nail, we wind the crawler coil until a piece of the match begins to scroll on the other side.

Let's put the reel on the floor. The rubber band, unwinding, will carry the reel, and the end of the nail will slide along the floor! No matter how simple this toy is, I knew guys who made several of these “crawlers” at once and staged entire “tank battles.” The reel that crushed the other one under itself, or knocked it over, or threw it off the table, won. The “vanquished” were removed from the “battlefield.” Having played enough with the crawling reel, remember that this is not just a toy, but a scientific instrument.

Scientific explanation

Where does friction occur here? Let's start with a piece of a match. When we wind the rubber band, it tightens and presses the fragment more and more tightly to the cheek of the reel. There is friction between the fragment and the cheek. If this friction did not exist, the piece of the match would spin completely freely and the crawler coil would not be able to be wound up even one turn! And to make it start even better, we make a hollow in the cheek for a match. This means that friction is useful here. It helps the mechanism we made work.

But with the other cheek of the coil the situation is completely opposite. Here the nail should rotate as easily as possible, as freely as possible. The easier it slides along the cheek, the farther the crawler reel will go. This means that friction is harmful here. It interferes with the operation of the mechanism. It needs to be reduced. That is why a soap washer is placed between the cheek and the nail. It reduces friction and acts as a lubricant.

Now let's look at the edges of the cheeks. These are the “wheels” of our toy; we’ll notch them with a knife. For what? Yes, so that they adhere better to the floor, so that they create friction and do not “slip,” as drivers and drivers say. This is where friction is helpful!

Yes, they have such a word. After all, in rain or ice, the wheels of the locomotive slip, spin on the rails, and it cannot move a heavy train. The driver has to turn on a device that pours sand onto the rails. For what? Yes, in order to increase friction. And when braking in icy conditions, sand also pours onto the rails. Otherwise you won’t be able to stop it! And special chains are put on the wheels of the car when driving on slippery roads. They also increase friction: they improve the grip of the wheels on the road.

Let's remember: friction stops the car when all the gas runs out. But if there were no friction of the wheels on the road, the car would not be able to move even with a full tank of gasoline. Its wheels would turn and slip, as if on ice!

Finally, the crawler reel has friction in one more place. This is the friction of the end of the nail on the floor along which it crawls following the coil. This friction is harmful. It interferes, it delays the movement of the coil. But it's difficult to do anything here. Unless you sand the end of the nail with fine sandpaper. No matter how simple our toy is, it helped to figure it out.

Where parts of the mechanism must move, friction is harmful and must be reduced. And where parts must not move, where good grip is needed, friction is useful and must be increased.

And friction is also needed in the brakes. The crawler doesn't have them; she can barely crawl anyway. And all real wheeled cars have brakes: driving without brakes would be too dangerous.(9)

Experience No. 2.« Wheel on a slide»

Materials: cardboard or thick paper, plasticine, paints (to paint the wheel)

Sequencing

It's rare to see a wheel roll up on its own. But we will try to make such a miracle. From cardboard or thick paper glue the wheel. On the inside we will stick a large piece of plasticine somewhere in one place.

Ready? Now let's put the wheel on an inclined plane (slide) so that a piece of plasticine is at the top and slightly on the uphill side. If you now let go of the wheel, then due to the additional load it will calmly roll upward! (2)

It really is going up. And then it stops altogether on the slope. Why? Remember the Vanka-Vstanka toy. When Vanka deviates and tries to put him down, the toy’s center of gravity rises. That's how it's made. So he strives for a position in which his center of gravity is the lowest, and... stands up. It looks paradoxical to us.

It's the same with a wheel on a slide.

Scientific explanation

When we stick plasticine, we shift the center of gravity of the object so that it will quickly return to a state of equilibrium (minimum potential energy, lowest position of the center of gravity) by rolling upward. And then, when this state is achieved, it stops altogether.

In both cases, there is a sinker inside the low-density volume (we have plasticine), as a result of which the toy tends to occupy a position strictly defined by the design, due to a shift in the center of gravity.

Everything in the world strives for a state of balance.(2)

1. Experiments and instruments on the topic “Hydrostatics”

Experiment No. 1 “Cartesian diver”

Materials: bottle, pipette (or matches weighted with wire), figurine of a diver (or any other)

Sequencing

This entertaining experience is about three hundred years old. It is attributed to the French scientist Rene Descartes (his last name is Cartesius in Latin). The experiment was so popular that a toy was created based on it, which was called the “Cartesian diver.” The device was a glass cylinder filled with water, in which a figurine of a man floated vertically. The figurine was in the upper part of the vessel. When the rubber film covering the top of the cylinder was pressed, the figure slowly sank down to the bottom. When they stopped pressing, the figure rose up.(8)

Let's make this experiment simpler: the role of the diver will be played by a pipette, and an ordinary bottle will serve as the vessel. Fill the bottle with water, leaving two to three millimeters to the edge. Let's take a pipette, fill it with some water and lower it into the neck of the bottle. Its upper rubber end should be at or slightly above the water level in the bottle. In this case, you need to ensure that with a slight push with your finger the pipette sinks, and then floats up on its own. Now, having attached thumb or the soft part of your palm to the neck of the bottle so as to close its opening, press on the layer of air that is above the water. The pipette will go to the bottom of the bottle. Release the pressure of your finger or palm and it will float up again. We slightly compressed the air in the neck of the bottle, and this pressure was transferred to the water.(9)

If at the beginning of the experiment the “diver” does not listen to you, then you need to adjust the initial amount of water in the pipette.

Scientific explanation

When the pipette is at the bottom of the bottle, it is easy to see how, as the pressure on the air in the neck of the bottle increases, water enters the pipette, and when the pressure is released, it comes out of it.

This device can be improved by stretching a piece of bicycle inner tube or balloon film over the neck of the bottle. Then it will be easier to control our “diver”. We also had matchstick divers swimming along with the pipette. Their behavior is easily explained by Pascal's laws. (4)

Experience No. 2. Siphon - "Vase of Tantalus"

Materials: a rubber tube, a transparent vase, a container (into which the water will go),

Sequencing

At the end of the last century there was a toy called “Tantalus Vase”. She, like the famous "Carthusian Diver", enjoyed great success with the public. This toy was also based on a physical phenomenon - on the action of a siphon, a tube from which water flows even when its curved part is above the water level. It is only important that the tube is first completely filled with water.

When making this toy you will have to use your sculpting abilities.

But where does such a strange name come from - “Vase of Tantalus”? There is a Greek myth about the Lydian king Tantalus, who was condemned to eternal torment by Zeus. He had to suffer from hunger and thirst all the time: standing in the water, he could not get drunk. The water teased him, rising all the way to his mouth, but as soon as Tantalus leaned a little towards it, it instantly disappeared. After some time, the water appeared again, disappeared again, and this continued all the time. The same thing happened with the fruits of the trees, with which he could satisfy his hunger. The branches instantly moved away from his hands as soon as he wanted to pick the fruits.

So, the toy that we can make is based on the episode with water, with its periodic appearance and disappearance. Take a plastic container from the cake packaging and drill a small hole in the bottom. If you don’t have such a vessel, you will have to take a liter jar and very carefully drill a hole in its bottom with a drill. Using round files, the hole in the glass can be gradually enlarged to the desired size.

Before sculpting a figurine of Tantalus, make a device for releasing water. A rubber tube is tightly inserted into the hole in the bottom of the vessel. Inside the vessel, the tube is bent into a loop, its end reaches the very bottom, but does not rest against the bottom. Top part the loops will have to be at the chest level of the future Tantalus figurine. After making notes on the tube, for ease of use, remove it from the vessel. Cover the loop with plasticine and shape it into a rock. And in front of it place a figurine of Tantalus sculpted from plasticine. It is necessary for Tantalus to stand at full height with his head tilted towards the future water level and his mouth open. Nobody knows how the mythical Tantalus was imagined, so don’t skimp on your imagination, even if it looks like a caricature. But in order for the figurine to stand steadily at the bottom of the vessel, sculpt it in a wide, long robe. Let the end of the tube, which will be in the vessel, peek out imperceptibly near the bottom of the plasticine rock.

When everything is ready, place the vessel on a board with a hole for the tube, and place a vessel under the tube to drain the water. Drape these devices so that it is not visible where the water disappears. When you pour water into the jar of Tantalum, adjust the stream so that it is thinner than the stream that will flow out.(4)

Scientific explanation

We have an automatic siphon. Water gradually fills the jar. The rubber tube is also filled to the very top of the loop. When the tube is full, water will begin to flow out and will continue to flow out until its level is lower than the outlet of the tube at Tantalus's feet.

The flow stops and the vessel fills again. When the entire tube is filled with water again, water will begin to flow out again. And this will continue as long as a stream of water flows into the vessel.(9)

Experience No. 3.« Water in a sieve»

Materials: bottle with cap, needle (to make holes in the bottle)

Sequencing

When the cap is not opened, the atmosphere forces water out of the bottle, which has tiny holes in it. But if you tighten the cap, only the air pressure in the bottle acts on the water, and its pressure is low and the water does not pour out! (9)

Scientific explanation

This is one of the experiments demonstrating Atmosphere pressure.

Experience No. 4.« The simplest fountain»

Materials: glass tube, rubber tube, container.

Sequencing

In order to build a fountain, take a plastic bottle with the bottom cut off or glass from a kerosene lamp, select a stopper to cover the narrow end. We will make a through hole in the cork. It can be drilled, pierced with a faceted awl, or burned through with a hot nail. A glass tube bent in the shape of the letter “P” or a plastic tube should fit tightly into the hole.

Pinch the hole in the tube with your finger, turn the bottle or lamp glass upside down and fill it with water. When you open the exit from the tube, water will flow out of it like a fountain. It will work until the water level in the large vessel is equal to the open end of the tube.(3)

Scientific explanation

I made a fountain that works on the property of communicating vessels .

Experience No. 5.« Floating bodies»

Materials: plasticine.

Sequencing

I know that bodies immersed in liquid or gas are acted upon by a force. But not all bodies float in water. For example, if you throw a piece of plasticine into water, it will drown. But if you make a boat out of it, it will float. This model can be used to study the navigation of ships.

Experience No. 6. "Drop of Oil"

Materials: alcohol, water, vegetable oil.

Everyone knows that if you drop oil on water, it will spread in a thin layer. But I placed a drop of oil in a state of weightlessness. Knowing the laws of floating of bodies, I created conditions under which a drop of oil takes on an almost spherical shape and is located inside the liquid.

Scientific explanation

Bodies float in a liquid if their density is less than the density of the liquid. IN volumetric figure The average density of a boat is less than the density of water. The density of oil is less than the density of water, but greater than the density of alcohol, so if you carefully pour alcohol into water, the oil will sink in the alcohol, but float at the interface between the liquids. Therefore, I placed a drop of oil in a state of weightlessness, and it takes on an almost spherical shape. (6)

1. Experiments and instruments on the topic “Thermal Phenomena”

Experience No. 1. "Convection currents"

Materials: paper snake, heat source.

Sequencing

There is a cunning snake in the world. She senses the movement of air currents better than people. Now we will check whether the air in a closed room is really so still.

Scientific explanation

The cunning snake really notices what people don't see. She feels when the air rises. With the help of convection, air flows move: warm air rises. He twirls the cunning snake. Convection currents constantly surround us in nature. In the atmosphere, convection currents are winds and the water cycle in nature.(9)

2.5 Experiments and instruments on the topic “Light phenomena”

Experience No. 1.« Pinhole camera»

Materials: cylindrical box of Pringles chips, thin paper.

Sequencing

A small camera obscura can easily be made from a tin, or better yet, from a cylindrical box of Pringles chips. On one side, a neat hole is pierced with a needle, on the other, the bottom is sealed with thin translucent paper. The camera obscura is ready.

But it’s much more interesting to take real photographs using a pinhole camera. In a matchbox painted black, cut a small hole, cover it with foil and pierce a tiny hole no more than 0.5 mm in diameter with a needle.

Pass the film through the matchbox, sealing all the cracks so as not to expose the frames. The “lens”, that is, the hole in the foil, needs to be sealed with something or covered tightly, simulating a shutter. (09)

Scientific explanation

The camera obscura operates on the laws of geometric optics.

2.6 Experiments and instruments on the topic “Electrical phenomena”

Experience No. 1.« Electric panty»

Materials: plasticine (to sculpt the head of a coward), ebonite shelves

Sequencing

Make a head out of plasticine with the most frightened face you can, and put this head on a fountain pen (closed, of course). Strengthen the handle in some kind of stand. From a staniol wrapper from processed cheese, tea, chocolate, make a hat for the coward and glue it to the plasticine head. Cut the “hair” from tissue paper into strips 2-3 mm wide and 10 centimeters long and glue it to the cap. These paper strands will hang out in disarray.

Now thoroughly electrify the wand and bring it to the panty. He is terribly afraid of electricity; the hair on his head began to move, touch the staniol cap with a stick. Even run the side of the stick along the free area of ​​the staniol. The horror of the electric panty will reach its limit: his hair will stand on end! Scientific explanation

Experiments with the coward showed that electricity can not only attract, but also repel. There are two types of electricity "+" and "-". What is the difference between positive and negative electricity? Like charges repel, and unlike charges attract.(5)

CONCLUSION

All phenomena observed during entertaining experiments have a scientific explanation; for this we used the fundamental laws of physics and the properties of the matter around us - the laws of hydrostatics and mechanics, the law of straightness of light propagation, reflection, electromagnetic interactions.

In accordance with the task, all experiments were carried out using only cheap, small-sized available materials; during their implementation, home-made devices were made, including a device for demonstrating electrification; the experiments were safe, visual, and simple in design

Conclusion:

Analyzing the results of entertaining experiments, I was convinced that school knowledge is quite applicable to solving practical issues.

I have carried out various experiments. As a result of observation, comparison, calculations, measurements, experiments, I observed the following phenomena and laws:

Natural and forced convection, Archimedes' force, floating of bodies, inertia, stable and unstable equilibrium, Pascal's law, atmospheric pressure, communicating vessels, hydrostatic pressure, friction, electrification, light phenomena.

I liked making homemade devices and conducting experiments. But there is a lot of interesting things in the world that you can still learn, so in the future:

I will continue to study this interesting science;

I hope that my classmates will be interested in this problem, and I will try to help them;

In the future I will conduct new experiments.

It is interesting to observe the experiment conducted by the teacher. Carrying it out yourself is doubly interesting. And conducting an experiment with a device made and designed with your own hands arouses great interest among the whole class. In such experiments it is easy to establish a relationship and draw a conclusion about how this installation works.

List of studied literature and Internet resources

M.I. Bludov “Conversations on Physics”, Moscow, 1974.

A. Dmitriev “Grandfather’s Chest”, Moscow, “Divo”, 1994.

L. Galpershtein “Hello, physics”, Moscow, 1967.

L. Galpershtein “Funny Physics”, Moscow, “Children’s Literature”, 1993.

F.V. Rabiz "Funny Physics", Moscow, "Children's Literature", 2000.

ME AND. Perelman “Entertaining tasks and experiments”, Moscow, “Children’s Literature” 1972.

A. Tomilin “I want to know everything”, Moscow, 1981.

Magazine " Young technician"

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