Elective course: "Practical and experimental physics." A system of experimental homework in physics using children's toys

In the first chapter thesis were considered theoretical aspects problems of using electronic textbooks in the process of teaching physics at the senior level of secondary schools. During theoretical analysis problems, we identified the principles and types of electronic textbooks, identified and theoretically substantiated the pedagogical conditions for the use of information technologies in the process of teaching physics at the senior level of secondary schools.

In the second chapter of the thesis, we formulate the purpose, objectives and principles of organizing experimental work. This chapter discusses the methodology for implementing the pedagogical conditions we have identified for the use of electronic textbooks in the process of teaching physics at the senior level of a comprehensive school; the final paragraph provides an interpretation and evaluation of the results obtained during the experimental work.

Purpose, objectives, principles and methods of organizing experimental work

In the introductory part of the work, a hypothesis was put forward that contained the main conditions that require testing in practice. In order to test and prove the proposals put forward in the hypothesis, we carried out experimental work.

Experiment at the Philosophical encyclopedic dictionary» is defined as a systematically conducted observation; systematic isolation, combination and variation of conditions in order to study the phenomena that depend on them. Under these conditions, a person creates the possibility of observations, on the basis of which his knowledge of the patterns in the observed phenomenon is formed. Observations, conditions and knowledge about patterns are the most significant, in our opinion, features that characterize this definition.

In the Psychology dictionary, the concept of experiment is considered as one of the main (along with observation) methods scientific knowledge in general, psychological research in particular. It differs from observation by active intervention in the situation on the part of the researcher, carrying out systematic manipulation of one or more variables (factors) and recording accompanying changes in the behavior of the object being studied. A properly conducted experiment allows you to test hypotheses about cause-and-effect relationships and is not limited to establishing a connection (correlation) between variables. The most significant features, as experience shows, here are: the activity of the researcher, characteristic of the exploratory and formative types of experiment, as well as testing the hypothesis.

Highlighting essential features of the given definitions, as A.Ya. rightly writes. Nain and Z.M. Umetbaev, can be built and used next concept: an experiment is a research activity designed to test a hypothesis, unfolding in natural or artificially created controlled and controlled conditions. The result of this, as a rule, is new knowledge, including the identification of significant factors influencing efficiency pedagogical activity. Organization of an experiment is impossible without identifying criteria. And it is their presence that makes it possible to distinguish experimental activity from any other. These criteria, according to E.B. Kainova, there may be the presence of: the purpose of the experiment; hypotheses; scientific language of description; specially created experimental conditions; diagnostic methods; ways of influencing the subject of experimentation; new pedagogical knowledge.

Based on their goals, they distinguish between ascertaining, formative and evaluative experiments. The purpose of the ascertaining experiment is to measure the current level of development. In this case, we receive primary material for research and organization of a formative experiment. This is extremely important for the organization of any survey.

A formative (transforming, training) experiment aims not at a simple statement of the level of formation of this or that activity, the development of certain skills of the subjects, but their active formation. Here it is necessary to create a special experimental situation. The results of an experimental study often do not represent an identified pattern, a stable dependence, but a series of more or less fully recorded empirical facts. This data is often descriptive in nature, representing only more specific material that narrows the further scope of the search. The results of an experiment in pedagogy and psychology should often be considered as intermediate material and a starting point for further research work.

Evaluation experiment (controlling) - with its help, after a certain period of time after the formative experiment, the level of knowledge and skills of the subjects is determined based on the materials of the formative experiment.

The purpose of the experimental work is to test the identified pedagogical conditions for the use of electronic textbooks in the process of teaching physics at the senior level of a secondary school and determine their effectiveness.

The main objectives of the experimental work were: selection of experimental sites for the pedagogical experiment; defining criteria for selecting experimental groups; development of tools and determination of methods for pedagogical diagnostics of selected groups; development of pedagogical criteria for identifying and correlating the levels of learning of students in control and experimental classes.

The experimental work was carried out in three stages, including: a diagnostic stage (carried out in the form of a confirmatory experiment); content stage (organized in the form of a formative experiment) and analytical (conducted in the form of a control experiment). Principles of carrying out experimental work.

The principle of comprehensiveness of scientific and methodological organization of experimental work. The principle requires ensuring a high level of professionalism of the experimental teacher himself. The effectiveness of the implementation of information technologies in teaching schoolchildren is influenced by many factors, and, undoubtedly, its basic condition is the correspondence of the content of training to the capabilities of schoolchildren. But even in this case, problems arise in overcoming intellectual and physical barriers, and therefore, when using methods of emotional and intellectual stimulation of students’ cognitive activity, we provided methodological counseling that meets the following requirements:

a) problem-search material was presented using personalized explanatory methods and instructions to facilitate students’ assimilation educational material;

b) various techniques and ways of mastering the content of the material being studied were proposed;

c) individual teachers had the opportunity to freely choose techniques and schemes for solving computerized problems, and work according to their original pedagogical techniques.

The principle of humanizing the content of experimental work. This is the idea of ​​the priority of human values ​​over technocratic, production, economic, administrative, etc. The principle of humanization was implemented by observing the following rules of pedagogical activity: a) the pedagogical process and educational relations in it are built on full recognition of the rights and freedoms of the student and respect for him;

b) know and during the pedagogical process rely on positive qualities schoolchild;

c) constantly carry out humanistic education of teachers in accordance with the Declaration of the Rights of the Child;

d) ensure the attractiveness and aesthetics of the pedagogical space and the comfort of the educational relations of all its participants.

Thus, the principle of humanization, as I.A. Kolesnikova and E.V. Titova believe, provides schoolchildren with a certain social protection in an educational institution.

The principle of democratization of experimental work is the idea of ​​​​presenting certain freedoms to participants in the pedagogical process for self-development, self-regulation, and self-determination. The principle of democratization in the process of using information technologies for teaching schoolchildren is implemented through compliance with the following rules:

a) create a pedagogical process open to public control and influence;

b) create legal support for the activities of students that help protect them from adverse environmental influences;

c) ensure mutual respect, tact and patience in the interaction between teachers and students.

The implementation of this principle helps to expand the capabilities of students and teachers in determining the content of education, choosing the technology for using information technology in the learning process.

The principle of cultural conformity of experimental work is the idea of ​​maximum use in upbringing, education and training of the environment in which and for the development of which the educational institution was created - the culture of the region, people, nation, society, country. The principle is implemented based on compliance with the following rules:

a) understanding of cultural and historical value by the teaching community at school;

b) maximum use of family and regional material and spiritual culture;

c) ensuring the unity of national, international, interethnic and intersocial principles in the upbringing, education, and training of schoolchildren;

d) the formation of creative abilities and attitudes of teachers and students to consume and create new ones cultural values.

The principle of a holistic study of pedagogical phenomena in experimental work, which involves: the use of systemic and integrative - developmental approaches; a clear definition of the place of the phenomenon being studied in the holistic pedagogical process; disclosure of the driving forces and phenomena of the objects being studied.

We were guided by this principle when modeling the process of using educational information technologies.

The principle of objectivity, which involves: checking each fact using several methods; recording all manifestations of changes in the object under study; comparison of the data from your study with data from other similar studies.

The principle was actively used in the process of conducting the ascertaining and formative stages of the experiment, when using the electronic process in the educational process, as well as in analyzing the results obtained.

The principle of adaptation, which requires taking into account the personal characteristics and cognitive abilities of students in the process of using information technology, was used when conducting a formative experiment. The principle of activity, which assumes that correction of the personal semantic field and behavioral strategy can only be carried out during the active and intensive work of each participant.

The principle of experimentation aimed at active search participants in classes on new behavior strategies. This principle is important as an impetus for the development of creativity and initiative of the individual, as well as as a model of behavior in the student’s real life.

We can talk about learning technology using electronic textbooks only if: it satisfies the basic principles educational technology(pre-design, reproducibility, targeting, integrity); it solves problems that were not previously theoretically and/or practically solved in didactics; The computer is the means of preparing and transmitting information to the learner.

In this regard, we present the basic principles of the systemic implementation of computers in educational process, which were widely used in our experimental work.

The principle of new tasks. Its essence is not to transfer traditionally established methods and techniques to the computer, but to rebuild them in accordance with the new capabilities that computers provide. In practice, this means that when analyzing the learning process, losses are identified that occur from shortcomings in its organization (insufficient analysis of the content of education, poor knowledge of the real educational capabilities of schoolchildren, etc.). In accordance with the result of the analysis, a list of tasks is outlined that, due to various objective reasons (large volume, enormous time expenditure, etc.) are currently not being solved or are being solved incompletely, but which can be completely solved with the help of a computer. These tasks should be aimed at the completeness, timeliness and at least approximate optimality of the decisions made.

The principle of a systems approach. This means that the introduction of computers must be based on system analysis learning process. That is, the goals and criteria for the functioning of the learning process must be determined, structuring must be carried out, revealing the entire range of issues that need to be resolved in order for the designed system to best meet the established goals and criteria.

Principles of the most reasonable typification of design solutions. This means that when developing software, the contractor must strive to ensure that the solutions he offers are suitable for the widest possible range of customers, not only in terms of the types of computers used, but also various types educational institutions.

In conclusion of this paragraph, we note that the use of the above methods with other methods and principles of organizing experimental work made it possible to determine the attitude towards the problem of using electronic textbooks in the learning process, and to outline specific ways effective solution problems.

Following the logic of theoretical research, we formed two groups - control and experimental. In the experimental group, the effectiveness of the selected pedagogical conditions was tested; in the control group, the organization of the learning process was traditional.

Educational features of the implementation of pedagogical conditions for the use of electronic textbooks in the process of teaching physics at senior levels are presented in paragraph 2.2.

The results of the work done are reflected in paragraph 2.3.

EXPERIMENTAL

TASKS

DURING TRAINING

PHYSICISTS

Sosina Natalia Nikolaevna

physics teacher

MBOU "Central Educational Center No. 22 - Lyceum of Arts"

Experimental problems play a big role in students' learning in physics. They develop thinking and cognitive activity, contribute to a deeper understanding of the essence of phenomena, and develop the ability to build a hypothesis and test it in practice. The main importance of solving experimental problems lies in the formation and development with their help of observation, measuring skills, and ability to handle instruments. Experimental tasks help to increase student activity in lessons and develop logical thinking, teach to analyze phenomena.

Experimental problems include those that cannot be solved without experiments or measurements. These problems can be divided into several types according to the role of experiment in the solution:

    Problems in which it is impossible to obtain an answer to the question without experiment;

    An experiment is used to create a problem situation;

    An experiment is used to illustrate a phenomenon about which we're talking about in the task;

    An experiment is used to verify the correctness of the solution.

You can solve experimental problems both in class and at home.

Let's look at some experimental problems that can be used in the classroom.

SOME CHALLENGING EXPERIMENTAL TASKS

    Explain the observed phenomenon

- If you heat the air in a jar and place a slightly inflated balloon with water on top of the neck of the jar, it will be sucked into the jar. Why?

(The air in the jar cools, its density increases, and its volume

decreases - the ball is drawn into the jar)

- If you pour water on a slightly inflated balloon hot water, then it will increase in size. Why?

(The air heats up, the speed of the molecules increases and they hit the walls of the ball more often. The air pressure increases. The shell is elastic, the pressure force stretches the shell and the ball increases in size)

- A rubber ball placed in a plastic bottle cannot be inflated. Why? What needs to be done to be able to inflate the balloon?

(The ball isolates the air atmosphere in the bottle. As the volume of the ball increases, the air in the bottle is compressed, the pressure increases and prevents the ball from inflating. If a hole is made in the bottle, the air pressure in the bottle will be equal to atmospheric pressure and the ball can be inflated).

- Is it possible to boil water in a matchbox?

    Calculation problems

- How to determine the loss of mechanical energy during one complete oscillation of the load?

(The energy loss is equal to the difference in the potential energy of the load in the initial and final positions after one period).

(To do this, you need to know the mass of the match and its burning time).

    Experimental tasks that encourage information seeking

to answer the question

- Bring a strong magnet to the head of the match, it is almost not attracted. Burn the sulfur head of the match and bring it to the magnet again. Why is the head of the match now attracted to the magnet?

Find information about the composition of a match head.

HOME EXPERIMENTAL TASKS

Experimental problems at home are of great interest to students. By making observations of any physical phenomenon, or performing an experiment at home that needs to be explained when completing these tasks, students learn to think independently and develop their practical skills. Performing experimental tasks plays a particularly important role in adolescence, since during this period the character is rebuilt educational activities schoolboy. A teenager is no longer always satisfied that the answer to his question is in a textbook. He has a need to obtain this answer from life experience, observations of the surrounding reality, from the results of his own experiments. Students complete home experiments and observations, laboratory work, and experimental tasks more willingly and with greater interest than other types of homework. The tasks become more meaningful, deeper, and interest in physics and technology increases. The ability to observe, experiment, research and design become an integral part in preparing students for further creative work in various fields of production.

Requirements for home experiments

First of all, this is, of course, safety. Since the experiment is carried out by the student at home independently without the direct control of the teacher, there should not be any chemicals and items that pose a threat to the health of the child and his home environment. The experiment should not require any significant material costs from the student; when conducting the experiment, objects and substances that are found in almost every home should be used: dishes, jars, bottles, water, salt, and so on. An experiment performed at home by schoolchildren should be simple in execution and equipment, but, at the same time, be valuable in the study and understanding of physics in childhood, and be interesting in content. Since the teacher does not have the opportunity to directly control the experiment performed by students at home, the results of the experiment must be formalized accordingly (approximately as is done when performing frontal exercises). laboratory work). The results of the experiment carried out by students at home should be discussed and analyzed in class. Students' work should not be a blind imitation of established patterns; they should contain the broadest manifestation of their own initiative, creativity, and search for something new. Based on the above, we can formulate requirements for household experimental tasks requirements:

– safety during implementation;
– minimal material costs;
– ease of implementation;
– have value in the study and understanding of physics;
– ease of subsequent control by the teacher;
– the presence of creative coloring.

SOME EXPERIMENTAL TASKS AT HOME

- Determine the density of a chocolate bar, a bar of soap, a juice bag;

- Take a saucer and lower it edgewise into a pan of water. The saucer is sinking. Now lower the saucer onto the water with its bottom, it floats. Why? Determine the buoyant force acting on the floating saucer.

- Make a hole in the bottom of the plastic bottle with an awl, quickly fill it with water and close the lid tightly. Why did the water stop pouring out?

- How to determine the muzzle velocity of a toy gun bullet using only a tape measure.

- The lamp cylinder says 60 W, 220 V. Determine the resistance of the spiral. Calculate the length of the lamp spiral if it is known that it is made of tungsten wire with a diameter of 0.08 mm.

- Write down the power of the electric kettle according to the passport. Determine the amount of heat released in 15 minutes and the cost of energy consumed during this time.

To organize and conduct a lesson with problematic experimental tasks, the teacher has a great opportunity to show his creative abilities, select tasks at his own discretion, designed for a particular class, depending on the level of preparation of the students. Currently exists large number methodological literature on which the teacher can rely when preparing for lessons.

You can use books such as

L. A. Gorev. Entertaining experiments in physics in grades 6-7 of secondary school - M.: “Prosveshcheniye”, 1985

V. N. Lange. Experimental physical tasks for ingenuity: Training manual. - M.: Nauka. Main editorial office of physical and mathematical literature, 1985

L. A. Gorlova. Non-traditional lessons, extracurricular activities - M.: “Vako”, 2006

V. F. Shilov. Home experimental assignments in physics. 7 – 9 grades. – M.: “School Press”, 2003

Some experimental problems are given in the appendices.

APPENDIX 1

(from the website of physics teacher V.I. Elkin)

Experimental tasks

1 . Determine how many drops of water are contained in a glass if you have a pipette, scales, a weight, a glass of water, a vessel.

Solution. Place, say, 100 drops into an empty vessel and determine their mass. How many times the mass of water in a glass is greater than the mass of 100 drops is the number of drops.

2 . Determine the area of ​​a homogeneous cardboard irregular shape, if you have scissors, a ruler, scales, weights.

Solution. Weigh the record. Cut out a regular shape from it (for example, a square), the area of ​​which is easy to measure. Find the mass ratio - it is equal to the area ratio.

3 . Determine the mass of a homogeneous cardboard of the correct shape (for example, a large poster), if you have scissors, a ruler, scales, and weights.

Solution. There is no need to weigh the entire poster. Determine its area, and then cut out a regular shape from the edge (for example, a rectangle) and measure its area. Find the area ratio - it is equal to the mass ratio.

4 . Determine the radius of the metal ball without using a caliper.

Solution. Determine the volume of the ball using a beaker, and from the formula V = (4/3) R 3 determine its radius.

Solution. Wind tightly around a pencil, for example, 10 turns of thread and measure the length of the winding. Divide by 10 to find the diameter of the thread. Using a ruler, determine the length of the coil, divide it by the diameter of one thread and get the number of turns in one layer. Having measured the outer and inner diameters of the coil, find their difference, divide by the diameter of the thread - you will find out the number of layers. Calculate the length of one turn in the middle part of the spool and calculate the length of the thread.

Equipment. Beaker, test tube, glass of cereal, glass of water, ruler.

Solution. Consider the grains to be approximately equal and spherical. Using the row method, calculate the diameter of the grain and then its volume. Pour water into the test tube with cereal so that the water fills the gaps between the grains. Using a beaker, calculate the total volume of the cereal. Dividing the total volume of the cereal by the volume of one grain, count the number of grains.

7 . In front of you is a piece of wire, a measuring ruler, wire cutters and a scale with weights. How to cut two pieces of wire at once (with an accuracy of 1 mm) in order to obtain homemade weights weighing 2 and 5 g?

Solution. Measure the length and weight of all the wire. Calculate the length of the wire per gram of its mass.

8 . Determine the thickness of your hair.

Solution. Wind coil by coil of hair onto the needle and measure the length of the row. Knowing the number of turns, calculate the diameter of the hair.

9 . There is a legend about the founding of the city of Carthage. Dido, the daughter of the Tyrian king, having lost her husband who was killed by her brother, fled to Africa. There she bought from the Numidian king as much land “as an oxhide occupies.” When the deal was completed, Dido cut the oxhide into thin strips and, thanks to this trick, covered a plot of land sufficient to build a fortress. So, it seems, the fortress of Carthage arose, and subsequently the city was built. Try to determine approximately how much area the fortress could occupy, if we assume that the size of the cowhide is 4 m2, and the width of the straps into which Dido cut it is 1 mm.

Answer. 1 km 2.

10 . Find out if the aluminum object (such as a ball) has a cavity inside.

Solution. Using a dynamometer, determine the weight of the body in air and water. In air P = mg, and in water P = mg – F, where F = gV is the Archimedes force. Using the reference book, find and calculate the volume of the ball V in air and water.

11 . Calculate the internal radius of a thin glass tube using a balance, a measuring ruler, or a container of water.

Solution. Fill the tube with water. Measure the height of the liquid column, then pour the water out of the tube and determine its mass. Knowing the density of water, determine its volume. From the formula V = SH = R 2 H, calculate the radius.

12 Determine the thickness of the aluminum foil without using a micrometer or caliper.

Solution. Determine the mass of the aluminum sheet by weighing, and the area using a ruler. Using a reference book, find the density of aluminum. Then calculate the volume and from the formula V = Sd - the thickness of the foil d.

13 . Calculate the mass of bricks in the wall of the house.

Solution. Since the bricks are standard, look for bricks in the wall whose length, thickness or width can be measured. Using a reference book, find the density of the brick and calculate the mass.

14 . Make a “pocket” scale to weigh liquid.

Solution. The simplest “scale” is a beaker.

15 . Two students made a task to determine the direction of the wind using a weather vane. On top they placed beautiful flags cut from the same piece of tin - on one weather vane a rectangular shape, on the other a triangular one. Which flag, triangular or rectangular, requires more paint?

Solution. Since the flags are made from the same piece of tin, it is enough to weigh them; the larger one has a larger area.

16 . Cover a piece of paper with a book and jerk it up. Why does a leaf rise behind it?

Answer. A piece of paper raises atmospheric pressure because... at the moment the book is torn off, a vacuum is formed between it and the leaf.

17 . How to pour water from a jar on the table without touching it?

Equipment. A three-liter jar, 2/3 filled with water, a long rubber tube.

Solution. Place one end of a long rubber tube completely filled with water into the jar. Take the second end of the tube into your mouth and suck out the air until the level of liquid in the tube is above the edge of the jar, then remove it from your mouth, and lower the second end of the tube below the water level in the jar - the water will flow by itself. (This technique is often used by drivers when pouring gasoline from a car tank into a canister).

18 . Determine the pressure exerted by a metal block lying tightly on the bottom of a vessel with water.

Solution. The pressure on the bottom of the glass consists of the pressure of the liquid column above the block and the pressure exerted on the bottom directly by the block. Using a ruler, determine the height of the liquid column, as well as the area of ​​the edge of the block on which it lies.

19 . Two balls of equal mass are immersed, one in clean water, the other in heavily salt water. The lever to which they are suspended is in balance. Determine which container contains clean water. You cannot taste the water.

Solution. A ball immersed in salt water loses less weight than a ball in clean water. Therefore, its weight will be greater, therefore, it is the ball that hangs on the shorter arm. If you remove the glasses, the ball suspended from the longer arm will be pulled.

20 . What needs to be done to make a piece of plasticine float in water?

Solution. Make a “boat” from plasticine.

21 . A plastic soda bottle was filled 3/4 with water. What needs to be done so that a plasticine ball thrown into a bottle will sink, but float up if the cork is twisted and the walls of the bottle are compressed?

Solution. You need to make an air cavity inside the ball.

22 . What pressure does a cat (dog) exert on the floor?

Equipment. A piece of checkered paper (from a student's notebook), a saucer with water, household scales.

Solution. Weigh the animal on a home scale. Wet his paws and make him run across a piece of squared paper (from a student's notebook). Determine the paw area and calculate the pressure.

23 . To quickly pour the juice out of the jar, you need to make two holes in the lid. The main thing is that when you start pouring the juice from the jar, they should be one at the top, the other diametrically at the bottom. Why are two holes needed and not one? Explanation. Air enters the top hole. Under the influence of atmospheric pressure, juice flows out from the bottom. If there is only one hole, then the pressure in the jar will periodically change, and the juice will begin to “gurgle.”

24 . A hexagonal pencil with a side width of 5 mm rolls along a sheet of paper. What is the trajectory of its center? Draw it.

Solution. The trajectory is a sinusoid.

25 . A dot was placed on the surface of the round pencil. The pencil was placed on an inclined plane and allowed to roll down while rotating. Draw the trajectory of the point relative to the table surface, magnified 5 times.

Solution. The trajectory is a cycloid.

26 . Hang the metal rod on two tripods so that its movement can be progressive; rotational.

Solution. Hang the rod on two threads so that it is horizontal. If you push it along, it will move while remaining parallel to itself. If you push it across, it will begin to oscillate, i.e. make a rotational movement.

27 . Determine the speed of movement of the end of the second hand of a wristwatch.

Solution. Measure the length of the second hand - this is the radius of the circle along which it moves. Then calculate the circumference, and calculate the speed

28 . Determine which ball has the most mass. (You cannot pick up the balls.)

Solution. Place the balls in a row and, using a ruler, simultaneously give everyone the same push force. The one that flies the shortest distance is the heaviest.

29 . Determine which of two seemingly identical springs has a greater stiffness coefficient.

Solution. Interlock the springs and stretch them in opposite directions. A spring with a lower stiffness coefficient will stretch more.

30 . You are given two identical rubber balls. How can you prove that one of the balls will bounce higher than the other if they are dropped from the same height? Throwing balls, pushing them against each other, lifting them from the table, rolling them around the table is prohibited.

Solution. You need to press the balls with your hand. Whichever ball is more elastic will bounce higher.

31 . Determine the coefficient of sliding friction of a steel ball on wood.

Solution. Take two identical balls, connect them together with plasticine so that they do not rotate when rolling. Place a wooden ruler in a tripod at such an angle that the balls sliding along it move straight and evenly. In this case = tg, where is the angle of inclination. By measuring the height of the inclined plane and the length of its base, find the tangent of this angle of inclination (sliding friction coefficient).

32 . You have a toy gun and a ruler. Determine the speed of the “bullet” when fired.

Solution. Make a shot vertically upward, note the height of the rise. At the highest point, kinetic energy is equal to potential energy - from this equality find the speed.

33 . A horizontally located rod with a mass of 0.5 kg lies at one end on a support, and at the other end on a removable table of a demonstration dynamometer. What are the dynamometer readings?

Solution. The total weight of the rod is 5 N. Since the rod rests on two points, the weight of the body is distributed equally on both points of support, therefore, the dynamometer will show 2.5 N.

34 . On the student's desk there is a cart with a load. The student pushes it slightly with his hand, and the cart, after traveling some distance, stops. How to find the initial speed of the cart?

Solution. Kinetic energy cart at the initial moment of its movement is equal to the work of the friction force along the entire path of movement, therefore, m 2 /2 = Fs. To find the speed, you need to know the mass of the cart with the load, the friction force and the distance traveled. Based on this, you need to have scales, a dynamometer, and a ruler.

35 . There is a ball and a cube made of steel on the table. Their masses are the same. You lifted both bodies and pressed them to the ceiling. Will they have the same potential energy?

Solution. No. The center of gravity of the cube is lower than the center of gravity of the ball, therefore, potential energy less ball.

APPENDIX 2

(from the book by V. N. Lange “Experimental physical tasks for ingenuity” - experimental tasks at home)

1. You were asked to find the density of sugar. How to do this, having only a household beaker, if the experiment needs to be carried out with granulated sugar?

2. Using a 100-gram weight, a triangular file and a graduated ruler, how can you approximately determine the mass of a certain body if it does not differ much from the mass of the weight? What to do if instead of a weight you are given a set of “copper” coins?

3. How can you find the mass of a ruler using copper coins?

4. The scale of the scales available in the house is graduated only up to 500 g. How can you use them to weigh a book whose mass is about 1 kg, also having a spool of thread?

5. At your disposal are a bathtub filled with water, a small jar with a wide neck, several penny coins, pipette, colored chalk (or soft pencil). How can you use these - and only these - objects to find the mass of one drop of water?

6. How can you determine the density of a stone using scales, a set of weights and a vessel with water if its volume cannot be measured directly?

7. How can you tell, given a spring (or a strip of rubber), twine and a piece of iron, which of two opaque vessels contains kerosene, and which contains kerosene and water?

8. How can you find the capacity (i.e., internal volume) of a pan using scales and a set of weights?

9. How to divide the contents of a cylindrical glass, filled to the brim with liquid, into two identical parts, having another vessel, but of a different shape and slightly smaller volume?

10. Two comrades were relaxing on the balcony and thinking about how to determine, without opening matchboxes, whose box had fewer matches left. What method can you suggest?

11. How to determine the position of the center of mass of a smooth stick without using any tools?

12. How to measure the diameter of a soccer ball using a rigid (for example, regular wooden) ruler?

13. How to find the diameter of a small ball using a beaker?

14. It is necessary to find out the diameter of a relatively thin wire as accurately as possible, having for this purpose only a school notebook “in a square” and a pencil. What should I do?

15. There is a rectangular vessel partially filled with water, in which a body immersed in water floats. How can you find the mass of this body using one ruler?

16. How to find the density of cork using a steel knitting needle and a beaker of water?

17. How, having only a ruler, can you find the density of the wood from which a stick is made floating in a narrow cylindrical vessel?

18. The glass stopper has a cavity inside. Is it possible to determine the volume of a cavity using scales, a set of weights and a vessel with water without breaking the stopper? And if it is possible, then how?

19. There is an iron sheet nailed to the floor, a light wooden stick (rod) and a ruler. Develop a method for determining the coefficient of friction between wood and iron using only the items listed.

20. Being in a room illuminated by an electric lamp, you need to find out which of two converging lenses with the same diameters has greater optical power. No special equipment is provided for this purpose. Indicate a way to solve the problem.

21. There are two lenses with the same diameters: one is converging, the other is diverging. How to determine which of them has greater optical power without resorting to instruments?

22. In a long corridor, devoid of windows, there is an electric lamp. It can be lit and extinguished using a switch installed at front door at the beginning of the corridor. This is inconvenient for those who go outside, since they have to make their way in the dark before going out. However, the one who entered and turned on the lamp at the entrance is also dissatisfied: after passing through the corridor, he leaves the lamp burning in vain. Is it possible to come up with a circuit that allows you to turn the lamp on and off from different ends of the corridor?

23. Imagine that you were asked to use an empty tin can and a stopwatch to measure the height of a house. Would you be able to cope with the task? Tell me how to proceed?

24. How to find the speed of flow of water from a water tap, having a cylindrical jar, a stopwatch and a caliper?

25. Water flows out in a thin stream from a loosely closed water tap. How, using only one ruler, can you determine the flow rate of water, as well as its volumetric flow rate (i.e., the volume of water flowing from the tap per unit time)?

26. It is proposed to determine the acceleration of gravity by observing a stream of water flowing from a loosely closed water tap. How to complete the task, having for this purpose a ruler, a vessel of known volume and a clock?

27. Let's say that you need to fill a large tank of known volume with water using a flexible hose equipped with a cylindrical nozzle. You want to know how long this boring activity will last. Is it possible to calculate it with only a ruler?

28. How can you determine the mass of an object using a weight of known mass, a light cord, two nails, a hammer, a piece of plasticine, mathematical tables and a protractor?

29. How to determine the pressure in a soccer ball using a sensitive scale and ruler?

30. How can you determine the pressure inside a burnt-out light bulb using a cylindrical vessel with iodine and a ruler?

31. Try to solve the previous problem if we are allowed to use a pan filled with water and a scale with a set of weights.

32. Given a narrow glass tube, sealed at one end. The tube contains air separated from surrounding atmosphere a column of mercury. There is also a millimeter ruler. Use them to determine atmospheric pressure.

33. How to determine the specific heat of vaporization of water, having a home refrigerator, a saucepan of unknown volume, a clock and an evenly burning gas burner? The specific heat capacity of water is assumed to be known.

34. You need to find out the power consumed from the city network by a TV (or other electrical appliance) using a table lamp, a spool of thread, a piece of iron and an electric meter. How to complete this task?

35. How to find the resistance of an electric iron in operating mode (there is no information about its power) using an electric meter and a radio receiver? Consider separately the cases of radios powered by batteries and the city network.

36. It’s snowing outside the window, but it’s warm in the room. Unfortunately, there is nothing to measure the temperature with - there is no thermometer. But there is a battery of galvanic cells, a very accurate voltmeter and ammeter, as much copper wire as you like, and a physical reference book. Is it possible to use them to find the air temperature in the room?

37. How to solve the previous problem if there is no physical reference book, but in addition to the listed items, you are allowed to use an electric stove and a pot of water?

38. The pole designations of the horseshoe magnet at our disposal have been erased. Of course, there are many ways to find out which one is southern and which is northern. But you are asked to complete this task using the TV! What should you do?

39. How to determine the pole signs of an unmarked battery using a coil of insulated wire, an iron rod and a TV.

40. How can you tell if a steel rod is magnetized, given a piece of copper wire and a spool of thread?

41. The daughter turned to her father, who was recording the electric meter readings by lamplight, with a request to let her go for a walk. Giving permission, the father asked his daughter to return in exactly an hour. How can a father control the duration of a walk without using a watch?

42. Problem 22 is published quite often in various collections and is therefore well known. Here is a task of the same nature, but somewhat more complex. Design a circuit that allows you to turn a light bulb or some other electrically powered device on and off from any number of different points.

43. If you place a wooden cube on a cloth-covered disk of a radiogram player close to the axis of rotation, the cube will rotate along with the disk. If the distance to the axis of rotation is large, the cube, as a rule, is thrown off the disk. How to determine the coefficient of friction of wood on cloth using just a ruler?

44. Develop a method for determining the volume of a room using a sufficiently long and thin thread, a clock and a weight.

45. When teaching music, ballet art, training athletes and for some other purposes, a metronome is often used - a device that produces periodic abrupt clicks. The duration of the interval between two beats (clicks) of the metronome is regulated by moving the weight on a special swinging scale. How to graduate the metronome scale in seconds using a thread, a steel ball and a tape measure if this is not done at the factory?

46. ​​The weight of a metronome with a non-graduated scale (see the previous problem) must be set in such a position that the time interval between two beats is equal to one second. For this purpose, you are allowed to use a long ladder, a stone and a tape measure. How should you use this set of items to complete the task?

47. There is a wooden cuboid, in which one edge is significantly larger than the other two. How to use a ruler alone to determine the coefficient of friction of a block on the floor surface in a room?

48. Modern coffee grinders are driven by a low-power electric motor. How to determine the direction of rotation of the rotor of its motors without disassembling the coffee grinder

49. Two hollow spheres having the same mass and volume are painted with the same paint, which is not advisable to scratch. One ball is made of aluminum and the other is made of copper. What is the easiest way to tell which ball is aluminum and which is copper?

50. How to determine the mass of a certain body using a uniform rod with divisions and a piece of not very thick copper wire? It is also allowed to use a physical reference book.

51. How to estimate the radius of a concave spherical mirror (or the radius of curvature of a concave lens) using a stopwatch and a steel ball of known radius?

52. Two identical spherical glass flasks are filled with different liquids. How to determine in which liquid the speed of light is greater, having only an electric light bulb and a sheet of paper for this purpose?

53. Dyed cellophane film can be used as a simple monochromator - a device that isolates a rather narrow range of light waves from a continuous spectrum. How to use a table lamp, a record player with a record (preferably a long-playing one), a ruler and a sheet of cardboard with a small hole to determine average length waves from this interval? It’s good if a friend with a pencil participates in your experiment.

Physics"

Uphysics teacher:

Gorsheneva Natalya Ivanovna

2011 G
The role of experiment in teaching physics.

Already in the definition of physics as a science there is a combination of both theoretical and practical parts. It is very important that in the process of teaching physics, the teacher can demonstrate to his students as fully as possible the interrelation of these parts. After all, when students feel this relationship, they will be able to give a correct theoretical explanation to many processes occurring around them in everyday life, in nature.

Without experiment there is no, and cannot be, rational teaching of physics; Just verbal teaching of physics inevitably leads to formalism and rote learning. The teacher's first thoughts should be aimed at ensuring that the student sees the experiment and does it himself, sees the device in the hands of the teacher and holds it in his own hands.

An educational experiment is a teaching tool in the form of specially organized and conducted experiments by a teacher and a student.


Objectives of the educational experiment:

  • Solving basic educational tasks;

  • Formation and development of cognitive and mental activity;

  • Polytechnic training;

  • Formation of students' worldview.
Experiment functions:

  • Cognitive (learning the basics of science in practice);

  • Educational (formation of a scientific worldview);

  • Developmental (develops thinking and skills).

Types of physical experiments.

What forms of practical training can be offered in addition to the teacher's story? First of all, of course, this is the observation by students of demonstrations of experiments carried out by the teacher in the classroom when explaining new material or when repeating what has been covered; it is also possible to offer experiments conducted by the students themselves in the classroom during lessons in the process of frontal laboratory work under the direct supervision of the teacher. You can also offer: 1) experiments conducted by the students themselves in the classroom during a physical workshop; 2) demonstration experiments conducted by students when answering; 3) experiments carried out by students outside of school on the teacher’s homework; 4) observations of short-term and long-term phenomena of nature, technology and everyday life, carried out by students at home on special instructions from the teacher.

What can be said about the above forms of training?

Demonstration experiment is one of the components of an educational physical experiment and is a reproduction of physical phenomena by a teacher on a demonstration table using special instruments. It refers to illustrative experiential teaching methods. The role of a demonstration experiment in teaching is determined by the role that the experiment plays in physics and science as a source of knowledge and a criterion of its truth, and its capabilities for organizing the educational and cognitive activities of students.

The significance of the demonstration physical experiment is that:

Students become familiar with the experimental method of knowledge in physics, with the role of experiment in physical research (as a result, they develop a scientific worldview);

Students develop some experimental skills: observe phenomena, put forward hypotheses, plan an experiment, analyze results, establish dependencies between quantities, draw conclusions, etc.

A demonstration experiment, being a means of clarity, helps organize students’ perception of educational material, its understanding and memorization; allows for polytechnic training of students; helps to increase interest in studying physics and create motivation to learn. But when a teacher conducts a demonstration experiment, the main activity is performed by the teacher himself and, at best, one or two students; the rest of the students only passively observe the experiment conducted by the teacher and do nothing themselves. with my own hands. Therefore, it is necessary to have independent experiments by students in physics.

Laboratory exercises.

When teaching physics in high school, experimental skills are developed when students themselves assemble installations, measure physical quantities, and perform experiments. Laboratory classes arouse great interest among students, which is quite natural, since in this case the student learns about the world around him on the basis of his own experience and his own feelings.

The importance of laboratory classes in physics lies in the fact that students develop ideas about the role and place of experiment in knowledge. When performing experiments, students develop experimental skills, which include both intellectual and practical skills. The first group includes the skills to: determine the purpose of the experiment, put forward hypotheses, select instruments, plan an experiment, calculate errors, analyze the results, draw up a report on the work done. The second group includes the skills to assemble an experimental setup, observe, measure, and experiment.

In addition, the significance of the laboratory experiment lies in the fact that when performing it, students develop such important personal qualities as accuracy in working with instruments; maintaining cleanliness and order in the workplace, in the notes made during the experiment, organization, persistence in obtaining results. They develop a certain culture of mental and physical labor.

In the practice of teaching physics at school, three types of laboratory classes have developed:

Frontal laboratory work in physics;

Physical workshop;

Home experimental work in physics.

Performing independent laboratory work.

Front laboratory work - this is the kind practical work when all students in a class simultaneously perform the same type of experiment using the same equipment. Front-end laboratory work is most often performed by a group of students consisting of two people; sometimes it is possible to organize individual work. Here a difficulty arises: the school physics classroom does not always have a sufficient number of sets of instruments and equipment to carry out such work. Old equipment becomes unusable, and, unfortunately, not all schools can afford to purchase new ones. And there’s no escaping the time limit. And if something doesn’t work out for one of the teams, some device doesn’t work or something is missing, then they start asking the teacher for help, distracting others from doing laboratory work.

Physical workshops are held in grades 9-11.

Physics workshop carried out with the aim of repeating, deepening, expanding and generalizing the knowledge gained from various topics of the physics course; development and improvement of students' experimental skills through the use of more complex equipment, more complex experiments; formation of their independence in solving problems related to the experiment. A physical workshop is held, usually at the end academic year, sometimes at the end of the first and second half of the year and includes a series of experiments on a particular topic. Students perform physical practical work in a group of 2-4 people using various equipment; During the next classes there is a change of work, which is done according to a specially designed schedule. When drawing up a schedule, take into account the number of students in the class, the number of workshops, and the availability of equipment. Two teaching hours are allocated for each physics workshop, which requires the introduction of double physics lessons into the schedule. This presents difficulties. For this reason and due to the lack of necessary equipment, one-hour physical workshops are practiced. It should be noted that two-hour work is preferable, since the work of the workshop is more complex than frontal laboratory work, they are performed on more complex equipment, and the share of independent participation of students is much greater than in the case of frontal laboratory work.

For each work, the teacher must draw up instructions, which should contain: title, purpose, list of instruments and equipment, brief theory, description of devices unknown to students, work plan. After completing the work, students must submit a report, which must contain: the title of the work, the purpose of the work, a list of instruments, a diagram or drawing of the installation, a plan for performing the work, a table of results, formulas by which the values ​​of quantities were calculated, calculations of measurement errors, conclusions. When assessing the work of students in a workshop, one should take into account their preparation for work, a report on the work, the level of development of skills, understanding of theoretical material, and the experimental research methods used.

What happens if the teacher invites students to perform an experiment or conduct an observation outside of school, that is, at home or on the street? experiments carried out at home should not require the use of any equipment or significant material costs. These should be experiments with water, air, and objects that are found in every home. Someone may doubt the scientific value of such experiments; of course, it is minimal. But is it bad if a child himself can check a law or phenomenon discovered many years before him? There is no benefit for humanity, but what is it for a child! Experience is a creative task; doing something on your own, the student, whether he wants it or not, will think about how easier it is to carry out the experiment, where he has encountered a similar phenomenon in practice, where else this phenomenon may be useful. What should be noted here is that children learn to distinguish physical experiments from all sorts of tricks, do not confuse one with the other.

Home experimental work. Home laboratory work is the simplest independent experiment that is performed by students at home, outside of school, without direct supervision by the teacher over the progress of the work.

The main objectives of experimental work of this type are:

Formation of the ability to observe physical phenomena in nature and in everyday life;

Formation of the ability to carry out measurements using measuring instruments used in everyday life;

Formation of interest in experiments and the study of physics;

Formation of independence and activity.

Home laboratory work can be classified depending on the equipment used to perform it:

Works in which household items and improvised materials are used (measuring cup, tape measure, household scales, etc.);

Works in which they are used homemade devices(lever scales, electroscope, etc.);

What does a child need to conduct the experiment at home? First of all, this is probably a fairly detailed description of the experience, indicating the necessary items, where it is said in a form accessible to the child what needs to be done and what to pay attention to. In addition, the teacher is required to provide detailed instructions.

Requirements for home experiments. First of all, this is, of course, safety. Since the experiment is carried out by the student at home independently, without the direct supervision of the teacher, the experiment should not contain any chemicals or objects that pose a threat to the health of the child and his home environment. The experiment should not require any significant material costs from the student; when conducting the experiment, objects and substances that are found in almost every home should be used: dishes, jars, bottles, water, salt, and so on. An experiment performed at home by schoolchildren should be simple in execution and equipment, but, at the same time, be valuable in the study and understanding of physics in childhood, and be interesting in content. Since the teacher does not have the opportunity to directly control the experiment performed by students at home, the results of the experiment must be formalized accordingly (approximately as is done when performing front-line laboratory work). The results of the experiment carried out by students at home should be discussed and analyzed in class. Students' work should not be a blind imitation of established patterns; they should contain the broadest manifestation of their own initiative, creativity, and search for something new. Based on the above, we will briefly formulate the requirements for home experimental tasks: requirements:

Safety during carrying out;

Minimum material costs;

Ease of implementation;

Ease of subsequent control by the teacher;

The presence of creative coloring.
The home experiment can be assigned after completing the topic in class. Then the students will see with their own eyes and be convinced of the validity of the theoretically studied law or phenomenon. At the same time, the knowledge obtained theoretically and tested in practice will be quite firmly embedded in their consciousness.

Or vice versa, you can set a home task, and after completing it, explain the phenomenon. Thus, it is possible to create among students problematic situation and move on to problem-based learning, which involuntarily gives rise to students cognitive interest to the material being studied, ensures the cognitive activity of students during training, leads to the development creative thinking students. In this case, even if schoolchildren cannot explain the phenomenon they experienced at home themselves, they will listen with interest to the teacher’s story.

Stages of the experiment:


  1. Justification for setting up the experiment.

  2. Planning and conducting the experiment.

  3. Evaluation of the result obtained.
Any experiment must begin with a hypothesis and end with a conclusion.


  1. Formulation and justification of a hypothesis that can be used as the basis for an experiment.

  2. Determining the purpose of the experiment.

  3. Clarification of the conditions necessary to achieve the stated goal of the experiment.

  4. Designing an experiment that includes answering the questions:

    • what observations to make

    • what quantities to measure

    • instruments and materials necessary for conducting experiments

    • the course of experiments and the sequence of their implementation

    • choosing a form for recording experiment results

  5. Selection of necessary instruments and materials

  6. Installation assembly.

  7. Conducting an experiment accompanied by observations, measurements and recording of their results

  8. Mathematical processing of measurement results

  9. Analysis of experimental results, formulation of conclusions
The general structure of a physical experiment can be represented as:

When conducting any experiment, it is necessary to remember the requirements for the experiment.

Requirements for the experiment:


  • Visibility;

  • Short term;

  • Persuasiveness, accessibility, reliability;

  • Safety.

In addition to the above types of experiments, there are mental, virtual experiments (see Appendix), which are carried out in virtual laboratories and have great value in case of lack of equipment.


Psychologists note that complex visual material is remembered better than its description. Therefore, a demonstration of experiments is captured better than a teacher’s story about a physical experiment.

School is the most amazing laboratory, because the future is created in it! And what it will be depends on us, teachers!

I believe that if a teacher in teaching physics uses an experimental method in which students are systematically involved in the search for ways to solve questions and problems, then we can expect that the result of training will be the development of versatile, original thinking, not constrained by narrow frameworks. A is the path to the development of high intellectual activity of students.

Application.
Classification of types of experiments.
Field

(excursions)


Home

School


Mental

Real

Virtual

Depending on quantity and size


Laboratory
Practical
demonstration

By venue

By method of implementation

Depending on the subject

Experiment


  Oscillations and waves.
  Optics.

Tasks for independent work.
 Problem 1. Hydrostatic weighing.
Equipment: wooden ruler length 40 cm, plasticine, a piece of chalk, a measuring cup with water, thread, a razor blade, a tripod with a holder.
 Exercise.
Measure

  • density of plasticine;
  • chalk density;
  • a mass of wooden ruler.

Notes:

  1. It is advisable not to wet the piece of chalk - it may fall apart.
  2. The density of water is considered equal to 1000 kg/m3

Problem 2. Specific heat of dissolution of hyposulfite.
When hyposulfite is dissolved in water, the temperature of the solution decreases greatly.
Measure the specific heat of solution of a given substance.
The specific heat of solution is the amount of heat required to dissolve a unit mass of a substance.
The specific heat capacity of water is 4200 J/(kg × K), the density of water is 1000 kg/m 3.
Equipment: calorimeter; beaker or measuring cup; scales with weights; thermometer; crystalline hyposulfite; warm water.

Problem 3. Mathematical pendulum and free fall acceleration.

Equipment: tripod with foot, stopwatch, piece of plasticine, ruler, thread.
Exercise: Measure the acceleration of gravity using a mathematical pendulum.

Problem 4. Refractive index of the lens material.
Exercise: Measure the refractive index of the glass the lens is made from.

Equipment: biconvex lens on a stand, light source (light bulb on a stand with a current source and connecting wires), screen on a stand, caliper, ruler.

Problem 5. “Rod vibrations”

Equipment: tripod with foot, stopwatch, knitting needle, eraser, needle, ruler, plastic cap from a plastic bottle.

  • Investigate the dependence of the oscillation period of the resulting physical pendulum on the length of the upper part of the spoke. Plot a graph of the resulting relationship. Check the feasibility of formula (1) in your case.
  • Determine, as accurately as possible, the minimum period of oscillation of the resulting pendulum.
  • Determine the value of the acceleration due to gravity.

Task 6. Determine the resistance of the resistor as accurately as possible.
Equipment: current source, resistor with known resistance, resistor with unknown resistance, glass (glass, 100 ml), thermometer, watch (you can use your wristwatch), graph paper, piece of foam plastic.

Problem 7. Determine the coefficient of friction of the block on the table.
Equipment: block, ruler, tripod, thread, weight of known mass.

Problem 8. Determine the weight of a flat figure.
Equipment: flat figure, ruler, weight.

Task 9. Investigate the dependence of the speed of the stream flowing out of the vessel on the height of the water level in this vessel.
Equipment: tripod with coupling and foot, glass burette with scale and rubber tube; spring clamp; screw clamp; stopwatch; funnel; cuvette; glass of water; sheet of graph paper.

Problem 10. Determine the temperature of water at which its density is maximum.
Equipment: glass of water, at temperature t = 0 °C; metal stand; thermometer; spoon; watch; small glass.

Problem 11. Determine the breaking force T threads, mg< T .
Equipment: a strip whose length 50 cm; thread or thin wire; ruler; load of known mass; tripod.

Problem 12. Determine the coefficient of friction of a metal cylinder, the mass of which is known, on the table surface.
Equipment: two metal cylinders of approximately the same mass (the mass of one of them is known ( m = 0.4 - 0.6 kg)); length ruler 40 - 50 cm; Bakushinsky dynamometer.

Task 13. Explore the contents of a mechanical “black box”. Determine the characteristics of a solid body enclosed in a “box”.
Equipment: dynamometer, ruler, graph paper, “black box” - a closed jar, partially filled with water, in which there is a solid body with a rigid wire attached to it. The wire comes out of the jar through a small hole in the lid.

Problem 14. Determine the density and specific heat capacity of an unknown metal.
Equipment: calorimeter, plastic beaker, bath for developing photographs, measuring cylinder (beaker), thermometer, threads, 2 cylinders of unknown metal, vessel with hot ( t g = 60° –70°) and cold ( t x = 10° – 15°) water. Specific heat capacity of water c in = 4200 J/(kg × K).

Problem 15. Determine the Young's modulus of steel wire.
Equipment: tripod with two legs for attaching equipment; two steel rods; steel wire (diameter 0.26 mm); ruler; dynamometer; plasticine; pin.
Note. The wire stiffness coefficient depends on the Young's modulus and the geometric dimensions of the wire as follows k = ES/l, Where l– wire length, a S– its cross-sectional area.

Task 16. Determine the concentration of table salt in the aqueous solution given to you.
Equipment: glass jar volume 0.5 l; a vessel with an aqueous solution of table salt of unknown concentration; AC power supply with adjustable voltage; ammeter; voltmeter; two electrodes; connecting wires; key; set of 8 weighed amounts of table salt; graph paper; container with fresh water.

Problem 17. Determine the resistance of a millivoltmeter and milliammeter for two measurement ranges.
Equipment: millivoltmeter ( 50/250 mV), milliammeter ( 5/50 mA), two connecting wires, copper and zinc plates, pickled cucumber.

Problem 18. Determine the density of the body.
Equipment: irregularly shaped body, metal rod, ruler, tripod, vessel with water, thread.

Task 19. Determine the resistances of resistors R 1, ..., R 7, ammeter and voltmeter.
Equipment: battery, voltmeter, ammeter, connecting wires, switch, resistors: R 1 – R 7.

Problem 20. Determine the spring stiffness coefficient.
Equipment: spring, ruler, sheet of graph paper, block, mass 100 g.
Attention! Do not suspend a load from a spring, as this will exceed the elastic deformation limit of the spring.

Problem 21. Determine the coefficient of sliding friction of a match head on the rough surface of a matchbox.
Equipment: box of matches, dynamometer, weight, sheet of paper, ruler, thread.

Problem 22. The fiber optic connector part is a glass cylinder (refractive index n= 1.51), in which there are two round cylindrical channels. The ends of the part are sealed. Determine the distance between channels.
Equipment: connector part, graph paper, magnifying glass.

Problem 23. “Black Vessel”. A body is lowered into a “black vessel” of water on a string. Find the density of the body ρ m, its height l the water level in the vessel with the immersed body ( h) and when the body is outside the liquid ( h o).
Equipment. “Black vessel”, dynamometer, graph paper, ruler.
Density of water 1000 kg/m 3. Vessel depth H = 32 cm.

Problem 24. Friction. Determine the sliding friction coefficients of wooden and plastic rulers on the table surface.
Equipment. Tripod with foot, plumb line, wooden ruler, plastic ruler, table.

Problem 25. Wind-up toy. Determine the energy stored in the spring of a wind-up toy (car) at a fixed “winding” (number of turns of the key).
Equipment: a wind-up toy of known mass, a ruler, a tripod with a foot and a coupling, an inclined plane.
Note. Wind up the toy so that its mileage does not exceed the length of the table.

Problem 26. Determining the density of bodies. Determine the density of the weight (rubber plug) and the lever (wooden strip) using the proposed equipment.
Equipment: load of known mass (marked plug); lever (wooden slats); cylindrical glass ( 200 - 250 ml); thread( 1 m); wooden ruler, vessel with water.

Problem 27. Studying the motion of the ball.
Raise the ball to a certain height above the table surface. Let's release him and watch his movement. If the collisions were absolutely elastic (sometimes they say elastic), then the ball would jump to the same height all the time. In reality, the height of the jumps is constantly decreasing. The time interval between successive jumps also decreases, which is clearly noticeable by ear. After some time, the bouncing stops and the ball remains on the table.
1 task – theoretical.
1.1. Determine the fraction of energy lost (energy loss coefficient) after the first, second, third rebound.
1.2. Obtain the dependence of time on the number of bounces.

Task 2 – experimental.
2.1. Using the direct method, using a ruler, determine the energy loss coefficient after the first, second, third impact.
It is possible to determine the energy loss coefficient using a method based on measuring the total time of motion of the ball from the moment it is thrown from a height H until the moment it stops bouncing. To do this, you have to establish the relationship between the total movement time and the energy loss coefficient.
2.2. Determine the energy loss coefficient using a method based on measuring the total time of motion of the ball.
3. Errors.
3.1. Compare the measurement errors of the energy loss coefficient in paragraphs 2.1 and 2.2.

Problem 28. Stable test tube.

  • Find the mass of the test tube given to you and its outer and inner diameters.
  • Calculate theoretically at what minimum height h min and maximum height h max of water poured into a test tube it will float stably in a vertical position, and find the numerical values ​​using the results of the first point.
  • Determine h min and h max experimentally and compare with the results of step 2.

Equipment. A test tube of unknown mass with a scale pasted on, a vessel with water, a glass, a sheet of graph paper, a thread.
Note. It is prohibited to peel off the scale from the test tube!

Problem 29. Angle between mirrors. Define dihedral angle between mirrors with the greatest accuracy.
Equipment. A system of two mirrors, a measuring tape, 3 pins, a sheet of cardboard.

Problem 30. Spherical segment.
A spherical segment is a body bounded by a spherical surface and a plane. Using this equipment, construct a graph of volume dependence V spherical segment of unit radius r = 1 from its height h.
Note. The formula for the volume of a spherical segment is not assumed to be known. Take the density of water equal to 1.0 g/cm3.
Equipment. A glass of water, a tennis ball of known mass m with a puncture, a syringe with a needle, a sheet of graph paper, tape, scissors.

Problem 31. Snow with water.
Define mass fraction snow in a mixture of snow and water at the time of issue.
Equipment. A mixture of snow and ice, a thermometer, a watch.
Note. Specific heat water c = 4200 J/(kg × °C), specific heat of melting of ice λ = 335 kJ/kg.

Problem 32. Adjustable “black box”.
In a “black box” with 3 outputs, an electrical circuit is assembled, consisting of several resistors with a constant resistance and one variable resistor. The resistance of the variable resistor can be changed from zero to a certain maximum value R o using an adjustment knob brought out.
Using an ohmmeter, examine the black box circuit and, assuming that the number of resistors in it is minimal,

  • draw a diagram of an electrical circuit contained in a “black box”;
  • calculate the resistance of constant resistors and the value of R o;
  • evaluate the accuracy of your calculated resistance values.

Problem 33. Measuring electrical resistance.
Determine the resistance of the voltmeter, battery and resistor. It is known that a real battery can be represented as an ideal one, connected in series with a certain resistor, and a real voltmeter can be represented as an ideal one, with a resistor connected in parallel.
Equipment. Battery, voltmeter, resistor with unknown resistance, resistor with known resistance.

Problem 34. Weighing ultra-light loads.
Using the proposed equipment, determine the mass m of a piece of foil.
Equipment. A jar of water, a piece of foam plastic, a set of nails, wooden toothpicks, a ruler with millimeter divisions or graph paper, a sharpened pencil, foil, napkins.

Problem 35. CVC CHA.
Determine the current-voltage characteristic (CVC) of the “black box” ( CHY). Describe the method for measuring the current-voltage characteristic and plot its graph. Assess the errors.
Equipment. FC limiting the resistor with a known resistance R, multimeter in voltmeter mode, adjustable current source, connecting wires, graph paper.
Attention. Connect CHY to the current source bypassing the limiting resistor is strictly prohibited.

Problem 36. Soft spring.

  • Experimentally investigate the dependence of the elongation of a soft spring under the action of its own weight on the number of coils of the spring. Give a theoretical explanation of the found relationship.
  • Determine the elasticity coefficient and mass of the spring.
  • Investigate the dependence of the period of oscillation of a spring on its number of turns.

Equipment: soft spring, tripod with foot, tape measure, clock with second hand, plasticine ball m = 10 g, graph paper.

Problem 37. Wire density.
Determine the density of the wire. Breaking the wire is not allowed.
Equipment: piece of wire, graph paper, thread, water, vessel.
Note. Density of water 1000 kg/m 3.

Problem 38. Friction coefficient.
Determine the coefficient of sliding friction of the bobbin material on wood. The bobbin axis must be horizontal.
Equipment: bobbin, thread length 0.5 m, wooden ruler fixed at an angle in a tripod, graph paper.
Note. During work, it is prohibited to change the position of the ruler.

Problem 39. The share of mechanical energy.
Determine the fraction of mechanical energy lost by the ball when falling without initial speed from above 1 m.
Equipment: tennis ball, ruler length 1.5 m, sheet of white paper format A4, sheet of copy paper, glass plate, ruler; brick.
Note: for small deformations of the ball, Hooke’s law can (but not necessarily) be considered valid.

Problem 40. Vessel with water “black box”.
The “black box” is a vessel with water into which a thread is lowered, on which two weights are attached at some distance from each other. Find the masses of the loads and their densities. Assess the size of the loads, the distance between them and the water level in the vessel.
Equipment: “black box”, dynamometer, graph paper.

Problem 41. Optical “black box”.
An optical “black box” consists of two lenses, one of which is converging and the other is diverging. Determine their focal lengths.
Equipment: tube with two lenses (optical “black” box), light bulb, current source, ruler, screen with a sheet of graph paper, sheet of graph paper.
Note. The use of light from a distant source is allowed. Bringing the light bulb close to the lenses (that is, closer than the stands allow) is not allowed.

Job description: This article may be useful to physics teachers working in grades 7-9 using programs from various authors. It provides examples of home experiments and experiments carried out using children's toys, as well as qualitative and experimental problems, including solutions, distributed by grade level. The material in this article can also be used by students in grades 7-9 who have an increased cognitive interest and desire to conduct independent research at home.

Introduction. When teaching physics, as is known, a demonstration and laboratory experiment is of great importance, bright and impressive, it affects the feelings of children and arouses interest in what is being studied. To create interest in physics lessons, especially in primary grades, you can, for example, demonstrate children's toys during lessons, which are often easier to use and more effective than demonstration and laboratory equipment. Using children's toys is very beneficial because... They make it possible to demonstrate very clearly, on objects familiar from childhood, not only certain physical phenomena, but also the manifestation of physical laws in the surrounding world and their application.

When studying some topics, toys will be almost the only visual aids. The method of using toys in physics lessons is subject to the requirements for various types school experiment:

1. The toy should be colorful, but without unnecessary details for the experience. All minor details that are not of fundamental importance in this experiment should not distract the attention of students and therefore they either need to be covered or made less noticeable.

2. The toy should be familiar to students, because increased interest in the design of the toy may obscure the essence of the demonstration itself.

3. Care should be taken to ensure the clarity and expressiveness of experiments. To do this, you need to choose toys that most simply and clearly demonstrate this phenomenon.

4. The experience must be convincing, not contain phenomena that are not relevant to the given issue and not give rise to misinterpretation.

Toys can be used during any stage training session: when explaining new material, during a frontal experiment, solving problems and consolidating material, but the most appropriate, in my opinion, is the use of toys in home experiments, independent research work Oh. The use of toys helps to increase the number of home experiments and research work, which undoubtedly contributes to the development of experimental skills and creates conditions for creative work on the material being studied, in which the main effort is directed not at memorizing what is written in the textbook, but at setting up an experiment and thinking about its result . Experiments with toys will be both learning and play for students, and such a game that certainly requires an effort of thought.



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