Computer Experiment Computer Experiment To give life to new design developments, introduce new technical solutions to production or check new ideas, you need an experiment. In the nearby past, such an experiment could be carried out either in the laboratory conditions on the installations specially created for it, or on nature, i.e. On this sample of the product, exposing it to all sorts of testing. This requires large material costs and time. Computer research of models came to help. When conducting a computer experiment, check the correctness of the construction of models. Learn the behavior of the model with various parameters of the object. Each experiment is accompanied by comprehension of results. If the results of the computer experiment contradict the meaning of the task is solved, then the error should be signed in the wrong selected model or in the algorithm and method of solving it. After detecting and eliminating errors, the computer experiment is repeated. To give life to new design developments, introduce new technical solutions to production or check new ideas, you need an experiment. In the nearby past, such an experiment could be carried out either in the laboratory conditions on the installations specially created for it, or on nature, i.e. On this sample of the product, exposing it to all sorts of testing. This requires large material costs and time. Computer research of models came to help. When conducting a computer experiment, check the correctness of the construction of models. Learn the behavior of the model with various parameters of the object. Each experiment is accompanied by comprehension of results. If the results of the computer experiment contradict the meaning of the task is solved, then the error should be signed in the wrong selected model or in the algorithm and method of solving it. After detecting and eliminating errors, the computer experiment is repeated.

Under the mathematical model, the system of mathematical relations of formulas, equations of inequalities, etc., reflecting the essential properties of the object or process. Under the mathematical model, the system of mathematical relations of formulas, equations of inequalities, etc., reflecting the essential properties of the object or process.

Modeling Tasks from various subject areas Problems for modeling from various subject areas Economics Economy Economics Astronomy Astronomy Astronomy Physics Physics Physics Ecology Ecology Ecology Biology Biology Biology Geography Geography Geography

Machine-building plant, selling products at bargain prices received a certain revenue, spending some amount of money on production. Determine the ratio of net profit to nested funds. Machine-building plant, selling products at bargain prices received a certain revenue, spending some amount of money on production. Determine the ratio of net profit to nested funds. Problem Statement Setting the task The purpose of modeling to explore the production process and sales process in order to gain the greatest net profit. Using economic formulas to find the ratio of net profit to nested funds. The purpose of modeling to explore the process of production and sales of products in order to gain the greatest net profit. Using economic formulas to find the ratio of net profit to nested funds.

The main parameters of the modeling object are: revenue, cost, profit, profitability, income tax. The main parameters of the modeling object are: revenue, cost, profit, profitability, income tax. Source data: source data: revenue B; revenue B; Costs (cost) S. Costs (cost) S. Other parameters will find using basic economic dependencies. The profit value is defined as the difference between the proceeds and the cost of P \u003d B-s. Other parameters will find using basic economic dependencies. The profit value is defined as the difference between the proceeds and the cost of P \u003d B-s. The profitability R is calculated by the formula:. The profitability R is calculated by the formula:. Profit corresponding to the maximum level of profitability of 50% is 50% of the cost of production S, i.e. S * 50/100 \u003d S / 2, Therefore, the income tax is determined as follows: the profit corresponding to the maximum level of profitability of 50% is 50% of the cost of production S, i.e. S * 50/100 \u003d S / 2, Therefore, the income tax n is defined as follows: if R

Analysis of the results Analysis of the results The resulting model allows, depending on profitability, determine the income tax, automatically recalculate the amount of net profit, find the ratio of net profit to the invested means. The model obtained allows, depending on the profitability, determines the income tax, automatically recalculate the amount of net profit, find the ratio of net profit to nested funds. The computer experiment shows that the ratio of net profit to nested means increases with increasing revenue and decreases with an increase in production costs. The computer experiment shows that the ratio of net profit to nested means increases with increasing revenue and decreases with an increase in production costs.

A task. A task. Determine the movement speed of the planets in orbit. To do this, make a computer model of the solar system. Setting the task The purpose of modeling to determine the speed of movement of the planets in orbit. The modeling object of the solar system, the elements of which are planets. The internal structure of the planets into the calculation is not accepted. We will consider planets as elements with the following characteristics: Name; R - remoteness from the Sun (in astronomical units; astronomer. Un. Average distance from the ground to the Sun); t - the period of circulation around the Sun (in years); V is the speed of the orbit (ASTR. / Year), assuming that the planets move around the Sun around the circles at a constant speed.

Analysis of results Analysis of results 1. Analyze the results of the calculations. Is it possible to argue that planets that are closer to the Sun have a greater speed of orbit? 1. Analyze the results of the calculations. Is it possible to argue that planets that are closer to the Sun have a greater speed of orbit? 2. The presented model of the solar system is static. When building this model, we neglected the range of distance from the planets to the Sun during their orbit movement. To know which planet further and what the approximate ratios between distances, this information is quite enough. If we want to determine the distance between the Earth and Mars, it is impossible to neglect temporary changes, and here you have to use a dynamic model. 2. The presented model of the solar system is static. When building this model, we neglected the range of distance from the planets to the Sun during their orbit movement. To know which planet further and what the approximate ratios between distances, this information is quite enough. If we want to determine the distance between the Earth and Mars, it is impossible to neglect temporary changes, and here you have to use a dynamic model.

Computer Experiment Enter the source data into the computer model. (For example: \u003d 0.5; \u003d 12) Find this coefficient of friction in which the machine will go from the mountain (at a given angle). Find such an angle in which the car will stand on the grief (with this friction coefficient). What will be the result, if the force of friction is neglected. Analysis of the results This computer model allows a computational experiment, instead of physical. Changing the values \u200b\u200bof the source data, you can see all changes occurring in the system. It is interesting to notice that in the constructed model, the result does not depend on the mass of the car, nor from accelerating the free fall.

A task. A task. Imagine that only one source of fresh water Lake Baikal will remain on Earth. How old Baikal will provide the population of the whole world with water? Imagine that only one source of fresh water Lake Baikal will remain on Earth. How old Baikal will provide the population of the whole world with water?

Development of a model Development of a model for constructing a mathematical model Determine the initial data. Denote: To build a mathematical model, we define the source data. Denote: V - Lake Lake Baikal km3; V - the volume of Lake Baikal km3; N - population of Earth 6 billion people; N - population of Earth 6 billion people; P - water consumption per day per person (on average) 300 liters. P - water consumption per day per person (on average) 300 liters. As 1l. \u003d 1 dm3 water, it is necessary to translate V water of the lake from km3 to DM3. V (km3) \u003d V * 109 (m3) \u003d V * 1012 (DM3) as 1l. \u003d 1 dm3 water, it is necessary to translate V water of the lake from km3 to DM3. V (km3) \u003d V * 109 (m3) \u003d V * 1012 (DM3) Result The number of years for which the population of the Earth uses the water of Baikal, denoted by g. So, G \u003d (V *) / (n * p * 365) Result The number of years for which the population of the Earth uses the water of Baikal, denoted by g. So, G \u003d (V *) / (N * P * 365) So the spreadsheet looks like in the formula display mode: this is how the spreadsheet looks like in the formula display mode:

A task. A task. For the production of vaccine at the factory it is planned to grow bacteria culture. It is known that if the mass of bacteria is x g, then in a day it will increase by (A-BX) X, where the coefficients A and B depend on the type of bacteria. The plant will take daily for the needs of the production of vaccine M G. Bacteria. To compile a plan, it is important to know how the mass of bacteria changes after 1, 2, 3, ..., 30 days .. For the production of vaccine at the factory, it is planned to grow culture of bacteria. It is known that if the mass of bacteria is x g, then in a day it will increase by (A-BX) X, where the coefficients A and B depend on the type of bacteria. The plant will take daily for the needs of the production of vaccine M G. Bacteria. To make a plan, it is important to know how the mass of bacteria varies after 1, 2, 3, ..., 30 days ..

Setting the problem. Setting the task of the modeling object is the process of changing the population depending on time. Many factors affect this process: ecology, health care, economic situation in the country, international situation and much more. Summarizing demographic data, scientists have derived a function expressing the dependence of the population of the population: the object of modeling is the process of changing the population of the population depending on the time. Many factors affect this process: ecology, health care, economic situation in the country, international situation and much more. He summarized demographic data, scientists removed a function expressing the dependence of the population of the population: f (t) \u003d where the coefficient a and b for each state of its own, f (t) \u003d where the coefficient A and B for each state of its own, E the base of the natural logarithm. E The base of the natural logarithm. This formula only approximately reflects reality. To find the values \u200b\u200bof the coefficients A and B, you can use the statistical directory. Taking the value of F (T) from the reference book (population at time T), it is possible to close a and b approximately to close theoretical values \u200b\u200bof F (T) calculated by the formula, did not differ much from the actual data in the directory. This formula only approximately reflects reality. To find the values \u200b\u200bof the coefficients A and B, you can use the statistical directory. Taking the value of F (T) from the reference book (population at time T), it is possible to close a and b approximately to close theoretical values \u200b\u200bof F (T) calculated by the formula, did not differ much from the actual data in the directory.

The use of a computer as a learning tool makes it possible to rethink traditional approaches to the study of many issues of natural science disciplines, strengthen the experimental activities of students, bring the learning process for the real process of knowledge based on modeling technology. The use of a computer as a learning tool makes it possible to rethink traditional approaches to the study of many issues of natural science disciplines, strengthen the experimental activities of students, bring the learning process for the real process of knowledge based on modeling technology. Solving tasks from various areas of human activity on the computer are based not only on the knowledge of the teaching technology of modeling, but, of course, on the knowledge of this subject area. In this regard, the proposed modeling lessons expediently carry out after studying the student of the material on a general educational subject, the computer science teacher needs to cooperate with teachers of various educational areas. Known experience of binary lessons, i.e. lessons conducted by teacher computer science with a subject teacher. Solving tasks from various areas of human activity on the computer are based not only on the knowledge of the teaching technology of modeling, but, of course, on the knowledge of this subject area. In this regard, the proposed modeling lessons expediently carry out after studying the student of the material on a general educational subject, the computer science teacher needs to cooperate with teachers of various educational areas. Known experience of binary lessons, i.e. lessons conducted by teacher computer science with a subject teacher.

| Planning lessons for school year | The main stages of modeling

Lesson 2.
The main stages of modeling

Having studied this topic, you will learn:

What is modeling;
- what can serve as a prototype for modeling;
- What a place is the modeling in human activity;
- What are the main stages of modeling;
- What is a computer model;
- What is a computer experiment.

Computer experiment

To give life to new design developments, introduce new technical solutions to production or check new ideas, you need an experiment. Experiment is an experience that is made with an object or model. It consists in performing certain actions and determining how the experimental sample reacts to these actions.

At school, you spend experiences in the lessons of biology, chemistry, physics, geography.

Experiments are carried out when testing new product samples in enterprises. Usually, a specially created installation is used for this, which allows experiment in laboratory conditions, or the real product itself is exposed to all kinds of tests (a nutrhea experiment). For the study, for example, its operational properties of a unit or node are placed in the thermostat, they are frozen in special chambers, they are tested on vibrationandes, and so well, if it is new hours or vacuum cleaner - not a lot of loss during destruction. And if the plane or rocket?

Laboratory and full-scale experiments require large material costs and time, but their meaning is nevertheless very large.

With the development of computer equipment, a new unique research method has appeared - a computer experiment. To help, and sometimes on replacing experimental samples and test stands in many cases, computer research of models came. The computed experimental experiment includes two stages: drawing up an experiment plan and research.

Experiment Plan

The experimental plan should clearly reflect the sequence of working with the model. The first point of such a plan is always testing the model.

Testing is the process of checking the correctness of the constructed model.

The test is a set of source data that allows you to determine the cultivation of the construction of the jelly.

To be confident in the correctness of the obtained modeling results, it is necessary: \u200b\u200b♦ check the developed model constructing algorithm; ♦ Ensure that the constructed model correctly reflects the properties of the original, which were taken into account when modeling.

To verify the correctness of the model constructing algorithm, a test set of source data is used for which the end result is known in advance or pre-determined by other methods.

For example, if you use calculated formulas during modeling, then you need to select several source data options and calculate them "manually". These are test tasks. When the model is built, you are tested with the same source data options and compare the simulation results with the outputs obtained by the calculation. If the results coincide, the algorithm is designed correctly, if not, it is necessary to search and eliminate the reason for their discrepancy. Test data may not completely reflect the real situation and do not bear the semantic content. However, the results obtained in the testing process can push you on the idea of \u200b\u200bchanging the original information or sign model, primarily in the part where the semantic content is laid.

To make sure that the constructed model reflects the properties of the original, which were taken into account when modeling, it is necessary to choose a test example with real source data.

Conducting research

After testing, when you have confidence in the correctness of the constructed model, you can move directly to the study.

The plan should provide an experiment or a series of experiments that satisfy modeling goals. Each experiment must be accompanied by an understanding of the results, which serves as the basis for analyzing the results of modeling and decision-making.

The preparation and conducting computer experiment is shown in Figure 11.7.

Fig. 11.7. Computer Experiment Scheme

Analysis of modeling results

The ultimate goal of modeling is the decision-making, which must be developed on the basis of a comprehensive analysis of modeling results. This stage is decisive - either you continue the study or finish. Figure 11.2 shows that the results of the analysis of the results cannot exist autonomously. The resulting conclusions often contribute to the implementation of an additional series of experiments, and sometimes a change in the task.

The basis for solving solutions is the results of testing and experiments. If the results do not correspond to the objectives of the task, it means that errors were made at the previous stages. This can be either incorrect setting of the problem, or too simplified construction of an information model, or an unsuccessful choice of method or modeling environment, or a violation of technological techniques in constructing a model. If such errors are revealed, then the model adjustment is required, that is, return to one of the previous steps. The process is repeated until the results of the experiment will not respond to modeling goals.

The main thing is to always remember: the identified error is also the result. How folk wisdom says, learn on errors. The great Russian poet A. S. Pushkin wrote about this:

Oh how much the discoveries are wonderful
Prepare the Enlightenment of Spirit
And experience, the son of difficult mistakes,
And genius, paradoxes friend,
And the case, God is inventor ...

Check questions and tasks

1. Name the two main types of modeling tasks.

2. In the famous "task book" of Oster there is a maximum task:

The evil sorceress, working not to twist the hands, turns into caterpillars of 30 princesses per day. How many days do she need to turn 810 princesses to the caterpillars? How many princesses in the day will have to turn into caterpillars to manage with work for 15 days?
What a question can be attributed to the type "What will happen if ...", and what - to the type "How to make ..."?

3. List the most well-known modeling objectives.

4. Formalize the humorous task from the "task" of Oster:

Of the two booths, located at a distance of 27 km one of the other, towards each other jumped at the same time two scarily dogs. The first runs at a speed of 4 km / h, and the second is 5 km / h.
How long will the fight begins?

5. Name as much characteristics of the "pair of shoes" as possible. Make an informational model of an object for different purposes:
■ Selection of shoes for a tourist campaign;
■ Selection of a suitable shoe box;
■ Buying a shoe care cream.

6. What are the characteristics of the teenager are essential for recommendation on the choice of profession?

7. What are the reasons for the computer widely used in modeling?

8. Name the computer simulation tools known to you.

9. What is a computer experiment? Give an example.

10. What is the testing of the model?

11. What errors are found in the process of modeling? What should I do when the error is detected?

12. What is the analysis of modeling results? What conclusions are usually done?

Experiment

Experiment (from lat. experimentum - Sample, experience) in the scientific method - the method of studying some phenomenon under control conditions. It differs from the observation of the active interaction with the studied object. Typically, the experiment is carried out within the framework of a scientific research and serves to test the hypothesis, establishing causal connections between phenomena. The experiment is the cornerstone of the empirical approach to knowledge. Popper's criterion puts forward the possibility of experimenting as the main difference of scientific theory from pseudo-scientific. An experiment is a research method that is reproduced in the unlimited number of times, and gives an identical result.

Experimental models

There are several models of the experiment: an impeccable experiment - in practice a model of an experiment used by psychologists-experimenters as a reference. In an experimental psychology, this term introduced Robert Gottsdanker, the author of the famous book "Fundamentals of the Psychological Experiment," that believed that the use of such a sample for comparison would lead to more efficient improvement of experimental techniques and identifying possible errors in planning and conducting a psychological experiment.

Random experiment (random test, random experience) is a mathematical model of the corresponding real experiment, the result of which is impossible to accurately predict. The mathematical model must meet the requirements: it must be adequate and adequately describe the experiment; The set of many observed results in the framework of the mathematical model under consideration with strictly defined fixed initial data described under the mathematical model was to be determined; There must be a fundamental ability to carry out an experiment with a random outcome of an pleasing number of times with unchanged input data; The requirement or a priori must be proved on the stochastic resistance of relative frequency for any observed result defined within the mathematical model.

The experiment is not always implemented as thought, therefore the mathematical equation of the relative frequency of the experimental implementation was invented:

Let there be some real experiment and albeit the result observed in the framework of this experiment. Let N be performed in which the result A can be realized or not. And let K be the number of implementations of the observed result A in N tests, believing that the tests produced are independent.

Types of experiments

Physical experiment

Physical experiment - The method of knowledge of nature, consisting in the study of natural phenomena in specially created conditions. Unlike theoretical physics, which explores the mathematical models of nature, the physical experiment is designed to explore the nature itself.

It is disagreement with the result of a physical experiment is the criterion of the erroneousness of the physical theory, or more precisely, the inapplicability of the theory to the world around us. The opposite statement is not true: an agreement with the experiment cannot be proof of the correctness (applicability) of the theory. That is, the main criterion of the viability of physical theory is the verification of the experiment.

Ideally, experimental physics should only give description Experiment results, without any of them interpretations. However, in practice it is unattainable. The interpretation of the results of a more or less complex physical experiment is inevitably based on the fact that we have an understanding of how all the elements of the experimental installation behave. Such an understanding, in turn, can not do not rely on any theory.

Computer experiment

Computer (numerical) Experiment is an experiment on a mathematical model of a computer research object, which is that, according to one model parameters, other parameters are calculated and the conclusions are made on the properties of the object described by the mathematical model. This type of experiment can only be conditionally attributed to the experiment, because it does not reflect natural phenomena, but only is the numerical implementation of a mathematical model created by man. Indeed, if incorrect in the mat. Models - its numerical solution can be strictly divergent with a physical experiment.

Psychological experiment

Psychological experiment - the experience held in special conditions for obtaining new scientific knowledge through the targeted intervention of the researcher in the vital activity of the subject.

Mind experiment

A mental experiment in philosophy, physics and some other areas of knowledge is the type of cognitive activity in which the structure of a real experiment is reproduced in the imagination. As a rule, a mental experiment is carried out within a certain model (theory) to verify its consistency. When conducting a mental experiment, the contradictions of the internal postulates of the model or their incompatibility with external (with respect to this model) are considered to be the principles that are considered certainly true (for example, with the law of energy conservation, the principle of causality, etc.).

Critical experiment

The critical experiment is an experiment, the outcome of which unequivocally determines whether a specific theory or hypothesis is true. This experiment must provide a predicted result that cannot be derived from other, generally accepted hypotheses and theories.

Literature

• Vizin V. P. Hermetics, Experiment, Miracle: Three aspects of the genesis of the new time science // Philosophical and religious origins of science. M., 1997. p.88-141.

Links

Wikimedia Foundation. 2010.

Synonyms:

Watch what is "Experiment" in other dictionaries:

- (from lat. Experimentum sample, experience), the method of cognition, with the help of crop in controlled and managed conditions, the phenomena of reality are investigated. E. is carried out on the basis of the theory that determines the setting of tasks and the interpretation of it ... ... Philosophical encyclopedia

experiment - A proposal to man in his will live, experience, feel the relevant for him or go to a conscious experiment, recreated during therapy a controversial or dubious situation for him (primarily in symbolic form). Short sensible ... ... Big psychological encyclopedia

No one believes in the hypothesis, except for the one who put forward it, but everyone believes in the experiment, except for the one who spent it. No amount of experiments cannot prove theory; But one experiment is enough to refute it ... Summary encyclopedia of aphorisms

Experiment - (Lat. EXPERIMENTUM - Sona, Baiқau, Tәzhіribe) - NәRSeler (Nometekleler) Men ұұ Balalstarta Batylanylatyn Zhona Baskarytn Zhodylard Grandsteyn Empirilyлыnқ Tan әdіsi. Experiment әDіs Retіnde Zhaңa Zalanda Pide Boldy (Gallee). Oyң philosophyclosure ... Philosophyclyard TermanderDің Sөzdigі.

- (Lat.). First experience; All that uses a naturalist to force under certain conditions, the forces of nature, as if artificially causing phenomena occurring in it. A dictionary of foreign words included in the Russian ... ... Dictionary of foreign words of the Russian language

See Experience ... Dictionary of Russian Synonyms and Similar expressions. under. ed. N. Abramova, M.: Russian Dictionaries, 1999. Experiment Test, experience, sample; Research, checking, attempt dictionary Russian synonyms ... Synonym dictionary

Experiment, experiment, husband. (Lat. Experimentum) (book.). Scientific experienced experience. Chemical experiment. Physical experiment. Experiment. || In general, experience, attempt. Educational work does not allow risky experiments ... ... Explanatory Dictionary Ushakov

Experiment - Experiment ♦ ExpéRimentation active, thoughtful experience; The desire does not so much to hear real reality (experience) and not even so much listen to it (observation), how much to try to ask her questions. There is a special concept ... ... Philosophical Dictionary Sponville

See the investigative experiment, Judicial Experiment ... Legal vocabulary

- (from Latin Experimentum sample, experience), the method of knowledge, with which the phenomena of nature and society are investigated in controlled and managed conditions. Often the main task of the experiment is the inspection of hypotheses and predictions of the theory (so ... ... Modern encyclopedia

- (from Lat. Experimentum sample, experience) study, study of economic phenomena and processes by reproducing them, modeling in artificial or natural conditions. The possibilities of economic experiments are very limited, since ... ... Economic Dictionary

Books

• Experiment, Stanislav Vladimirovich Borzov, this book offers to look at what is happening with us now and what time ago under the new angle of view. In essence, we are watching an experiment with their scope, ... Category: Biology Publisher:

L. V. Pigalitsyn,
, www.levpi.narod.ru, MOU SOSH No. 2, Dzerzhinsk, Nizhny Novgorod region.

Computer physical experiment

4. Computing Computer Experiment

Computational experiment turns
in an independent area of \u200b\u200bscience.
R.G. EFREMOV, DF-M.N.

The computational computer experiment is largely similar to the usual (toast). These are experimental planning, and the creation of an experimental installation, and performing control tests, and conducting a series of experiments, and processing experimental data, their interpretation, etc. However, it is not performed above the real object, but over its mathematical model, the role of the experimental installation plays equipped with a special computer program.

The computing experiment is becoming more and more popular. They are engaged in many institutes and universities, for example, in Moscow State University. M.V. Lomonosov, IFSU, Institute of Cytology and Genetics, SB RAS, Institute of Molecular Biology of the Russian Academy of Sciences, etc. Scientists can already receive important scientific results without real, "wet" experiment. For this, there are not only computer power, but also the necessary algorithms, and most importantly - understanding. If used to be divided - in vivo, in vitro- then now added more in silico.. In fact, the computing experiment becomes an independent science area.

The advantages of such an experiment are obvious. He is usually cheaper to the intensive. It can be easily and safely interfere. It can be repeated and interrupted at any time. During this experiment, you can simulate conditions that cannot be created in the laboratory. However, it is important to remember that the computing experiment cannot completely replace the naturic, and the future is for their reasonable combination. The computing computer experiment serves as a bridge between the attendant experiment and theoretical models. The starting point of numerical modeling is the development of an idealized model of the physical system under consideration.

Consider several examples of a computational physical experiment.

Moment of inertia. In "Open Physics" (2.6, part 1) there is an interesting computing experiment to find the moment of inertia of a solid body on an example of a system consisting of four balls strung on one needle. You can change the position of these balls on the needle, as well as choose the position of the rotation axis, conducting it both through the center of the knitting, and through its ends. For each location of the balls, students are calculated using the Steiner Theorem on the parallel transfer of the rotation axis value of the moment of inertia. Data for calculations report teacher. After calculating the moment of inertia, the data is entered into the program and the results obtained by students are checked.

"Black box". To implement a computational experiment, we have created several programs for the study of the contents of an electric "black box". It may contain resistors, incandescent bulbs, diodes, capacitors, coils, etc.

It turns out that in some cases it is possible, without opening the "black box", find out its contents, connecting various devices to the input and output. Of course, at the school level, this can be done for a simple three-or four-pole. Such tasks are developing the imagination of students, spatial thinking and creative abilities, not to mention that to solve them it is necessary to have deep and strong knowledge. Therefore, it is not by chance that at many All-Union and International Olympiads in physics as experimental tasks proposes a study of "black boxes" on mechanics, warmth, electricity and optics.

In the Speed \u200b\u200bCourses, I spend three real laboratory work when in the "black box":

- only resistors;

- resistors, incandescent lamps and diodes;

- resistors, condensers, coils, transformers and oscillatory contours.

Structurally "black boxes" are made in empty match boxes. Inside the box is placed the electrical circuit, and the boxes are rushed with scotch. Studies are carried out using instruments - autometers, generators, oscilloscopes, etc., because For this you have to build Wah and Ahh. Appliance testimony Students are introduced into a computer that processes the results and builds VAC and Ahh. This allows students to find out what details is in the "black box", and determine their parameters.

When carrying out frontal laboratory work with "black boxes", difficulties associated with lack of instruments and laboratory equipment arise. Indeed, because for research it is necessary to have, say, 15 oscilloscopes, 15 sound generators, etc., i.e. 15 sets of expensive equipment, which most schools do not have. And here the virtual "black boxes" come to the rescue - relevant computer programs.

The advantage of these programs is that research can be carried out simultaneously by the whole class. As an example, we consider a program that implements with the help of a generator of random numbers "Black boxes" containing only resistors. On the left side of the desktop there is a "black box". It has an electrical circuit, consisting only of resistors that can be located between points. A, B, with and D..

At the disposal of the student there are three instruments: a power source (its internal resistance to simplify calculations is taken equal to zero, and EMF is generated by a random program); voltmeter (internal resistance equal to infinity); Ampmeter (internal resistance is zero).

When you start the program inside the "black box", an electrical circuit containing from 1 to 4 resistors is randomly generated. The student can make four attempts. After pressing any key, it is proposed to connect to the terminals of the "black box" any of the proposed devices in any sequence. For example, he connected to the terminals AU The current source with EDC \u003d 3 V (the value of the EDC is generated by the program randomly, in this case it turned out 3 V). To terminals CD I connected a voltmeter, and its testimony was 2.5 V. From this it should be concluded that there is at least a voltage divider in the "black box". To continue the experiment, an ammeter can be connected instead of a voltmeter and remove the readings. This data is clearly not enough for the mystery. Therefore, you can spend two more experiments: the current source connects to the terminals CD, and a voltmeter and an ammeter - to the terminals AU. The data obtained in this will be quite enough to solve the contents of the "black box". The student on paper draws a scheme, calculates the parameters of the resistors and shows the results of the teacher.

A teacher, checking the work, enters the appropriate code to the program, and a scheme appears on the desktop inside this "black box" and the parameters of the resistors.

The program is written by my students in Baysik. To run it in Windows XP. or in Windows Vista. You can use the emulator program DOS., eg, Dosbox.. You can download it from my site www.physics-computer.by.ru.

If inside the "black box" there are nonlinear elements (incandescent lamps, diodes, etc.), then besides immediate measurements, it will have to remove the Wah. For this purpose, it is necessary to have a current source, voltage, on the outputs of which the voltage can be changed from 0 to some value.

To study inductors and containers, it is necessary to remove the frequency response, using the virtual sound generator and the oscilloscope.

Speed \u200b\u200bselector. Consider another program from "open physics" (2.6, part 2), which allows a computational experiment with the velocity selector in the mass spectrometer. To determine the mass of the particle using a mass spectrometer, it is necessary to perform a preliminary choice of charged particles in speeds. This goal and serve so-called speed \u200b\u200bselectors.

In the simplest velocity selector, the charged particles move in crossed homogeneous electrical and magnetic fields. The electric field is created between the plates of the flat capacitor, magnetic - in the clearance of the electromagnet. starting speed υ Charged particles aimed perpendicular to vectors E. and IN .

There are two strength on the charged particle: electric power q. E. and magnetic power Lorentz q. υ × B. . Under certain conditions, these forces may accurately balancing each other. In this case, the charged particle will move evenly and straight. Flying through the condenser, the particle will pass through a small hole on the screen.

The condition of the straight trajectory of the particle does not depend on the charge and mass of the particle, and depends only on its speed: qE \u003d QυB.→ υ \u003d E / B.

In a computer model, you can change the voltage values \u200b\u200bof the electric field E, the induction of the magnetic field B. and initial particle speed υ . Experience in selections of speeds can be performed for an electron, proton, α-particles and completely ionized uranium-235 and uranium-238 atoms. The computational experiment in this computer model is carried out as follows: students report on which the charged particle flies into the velocity selector, the electric field strength and the initial velocity of the particle. Students calculate the induction of the magnetic field according to the above formulas. After that, the data is introduced into the program and observe the particle flying. If the particle flies inside the velocity selector horizontally, then the calculations are true.

More complex computing experiments can be spent by applying a free package. "Model Vision for Windows". Package ModelVisionStudium (MVS) It is an integrated graphical shell of the rapid creation of interactive visual models of complex dynamic systems and carrying out computational experiments with them. The package was developed by the Experimental Object Technology Research Group at the Department of Distributed Calculations and Computer Networks Faculty of Technical Cybernetics of St. Petersburg State Technical University. Free package free MVS. 3.0 is available at www.exponenta.ru. Modeling technology in environment MVS. Based on the concept of a virtual laboratory stand. On the stand, the user is placed virtual blocks of the simulated system. Virtual blocks for the model are selected either from the library, or are created by the user again. Package MVS. Designed to automate the main stages of the computing experiment: constructing a mathematical model of the object under study, generating a software implementation of the model, studies of the properties of the model and representing the results in a form convenient for analysis. The object under study may refer to the class of continuous, discrete or hybrid systems. The package is best adapted to study complex physical and technical systems.

As an example Consider a fairly popular task. Let the material point thrown at some angle to the horizontal plane and absolutely elastically constructs with this plane. This model has become almost mandatory in the demonstration set of examples of modeling packages. Indeed, this is a typical hybrid system with continuous behavior (flight in the field) and discrete events (bounce). This example also illustrates an object-oriented approach to modeling: a ball flying in the atmosphere is a descendant of a ball flying in an airless space, and automatically inherits all common features by adding its own characteristics.

The latter, final, from the user's point of view, the modeling step, is the stage of describing the form of representation of the results of the computing experiment. These can be tables, graphs, surfaces and even animation illustrating real-time results. Thus, the user really observes the system dynamics. You can move dots in the phase space drawn by the user elements of the design, the color gamut can vary, and the user can follow on the screen, for example, behind heating or cooling processes. In the models created software packages, you can provide special windows that allow you to change the parameter values \u200b\u200bin the course of the computing experiment, and immediately see the effects of changes.

A lot of work on visual modeling of physical processes in MVS. It is carried out in the IGSU. There developed a number of virtual work on the course of general physics, which can be associated with real experimental settings, which makes it possible to simultaneously observe the change in parameters as a real physical process and the parameters of its model, clearly demonstrating its adequacy. As an example, we give seven laboratory work on mechanics from the laboratory workshop of the Internet portal of an open education, which meets the existing state educational standards in the specialty "Teacher of Physics": the study of a straight line with the help of the ATRUD machine; Measurement of the speed of the bullet; Addition of harmonic oscillations; Measurement of the moment of inertia of the bike wheel; study of the rotational movement of the solid body; determination of acceleration of free fall using a physical pendulum; Study of free fluctuations in physical pendulum.

The first six are virtual and are modeled on PCs in ModelvisionStudiumfreeAnd the latter has both a virtual option and two real. In one, intended for distance learning, the student must independently make a pendulum from a large stationery clips and an eraser and hanging it under a computer mouse shaft without a ball, get a pendulum, whose deviation angle is read by a special program and should be used by students when processing the results of the experiment. Such an approach allows part of the skills necessary for experimental work, to work out only on a PC, and the rest of the part - when working with available real appliances and with remote access to equipment. In another embodiment, intended for home preparation of full-time students to perform laboratory work in the workshop of the department of general and experimental physics of the Physical Faculty of MPGU, the student exercises the skills of working with experimental installation on a virtual model, and in the laboratory conducts an experiment at the same time on a specific real installation and with its virtual model. At the same time, it uses both traditional measurement means in the form of an optical scale and a stopwatch, as well as more accurate and high-speed means - a sensor of displacements based on an optical mouse and a computer timer. The simultaneous comparison of all three representations (traditional, specified using electronic sensors associated with a computer, and model) of the same phenomenon allows us to conclude about the limits of the model's adequacy, when data of computer simulation starts after a while more and more different from the readings, Removed on a real installation.

The ones are not exhausted, the possibilities of using a computer in a physical computing experiment are not exhausted. So, for a creative working teacher and his students, there will always be unused possibilities in the field of virtual and real physical experiment.

If you have comments and suggestions on various types of physical computer experiment, write to me at:

The computer experiment with the system model during its study and design is carried out in order to obtain information on the characteristics of the functioning of the object under consideration. The main task of planning computer experiments is to obtain the necessary information about the system under study during restrictions on resources (machine time costs, memory, etc.). Competitious tasks solved when planning computer experiments include the tasks of reducing machine time costs for modeling, increasing the accuracy and reliability of modeling results, test adequacy, etc.

The efficiency of computer experiments with models significantly depends on the choice of an experimental plan, since it is the plan that determines the volume and procedure for conducting computing on computer, receiving accumulation and statistical processing of system modeling results . Therefore, the main task of planning computer experiments with the model is formulated as follows: it is necessary to obtain information about the modeling object specified in the form of an algorithm (program), with minimal or limited costs of machine resources to implement the modeling process.

The advantage of computer experiments before home is the ability to fully reproduce the experimental conditions with the system under study. . Essential advantage over the field is the simplicity of interrupting and resuming computer experiments, which allows the use of successive and heuristic planning techniques that may be unrealized in experiments with real objects. When working with a computer model, an experiment is always possible for the time required to analyze the results and making decisions on its further progress (for example, the need to change the values \u200b\u200bof the characteristics of the model).

The disadvantage of computer experiments is that the results of some observations depend on the results of one or more of the previous ones, and therefore they contain less information than in independent observations.

With regard to the database, the computer experiment means data manipulation in accordance with the goal using DBMS tools. The purpose of the experiment can be formed on the basis of the general purpose of modeling and taking into account the requirements of a particular user. For example, there is a Database "Deanat". The overall goal of creating this model is to manage the educational process. If you need to obtain information about student performance, you can request, i.e. Implement an experiment for sampling the desired information.

The DBMS Environment Toolbox allows the following data operations to perform:

1) sorting - streamlining data according to any sign;

2) Search (filtering) - selection of data satisfying a certain condition;

3) Creating calculated fields - data transformation into another view based on formulas.

The information model management is inextricably linked with the development of various criteria for searching and sorting data. Unlike paper files, where sorting is possible on one or two criteria, and the search is generally carried out manually - brute force cards, computer databases allow you to set any sorting forms over different fields and a variety of search criteria. A computer without time spending on a given criterion sorts or select the necessary information.

To successfully work with the information model, the database software environments allow you to create calculated fields in which the initial information is converted into another species. For example, according to the semester, with the help of a special built-in function, you can calculate the average student performance score. Such calculated fields are used either as additional information, or as a criterion for search and sorting.

A computer experiment includes two stages: Testing (verification of the execution of operations) and conducting an experiment with real data.

After drawing up the formulas for the calculated fields and filters, you must make sure that they are correct. To do this, you can enter test records for which the result of the operation is known in advance.

A computer experiment is completed by issuing results in a convenient analysis and decision making. One of the advantages of computer information models is the ability to create various forms of presenting output information called reports. Each report contains information that meets the objectives of a particular experiment. The convenience of computer reports is that they allow them to group information on specified features, enter the summary fields of counting records in groups and in general throughout the database and further use this information to make a decision.

The environment allows you to create and store multiple typical, frequently used report forms. According to the results of some experiments, you can create a temporary report that is deleted after copying it to a text document or printout. Some experiments do not at all require the reporting. For example, it is required to choose the most successful student to assign high scholarships. To do this, it is enough to sort the average score of the semester. The required information will contain the first entry in the list of students.