LESSON PLAN
Topic: “Magnetic flux. The phenomenon of electromagnetic induction", 9th grade
Lesson objectives:
The goal is to achieve educational results.
Personal results:
– development of cognitive interests, intellectual and creative abilities;
– independence in acquiring new knowledge and practical skills;
– formation of value attitudes towards learning outcomes.
Meta-subject results:
– mastering the skills of independently acquiring new knowledge, organizing educational activities, setting goals, planning;
– mastering methods of action in non-standard situations, mastering heuristic methods of problem solving;
– developing the skills to observe, highlight the main thing, and explain what is seen.
Subject results:
– know: magnetic flux, induced current, the phenomenon of electromagnetic induction;
– understand: concept of flux, phenomenon of electromagnetic induction
– be able to: determine the direction of the induction current, solve typical OGE problems.
Lesson type: learning new material
Lesson format: lesson study
Technologies: elements of critical thinking technology, problem-based learning, ICT, problem-based dialogue technology
Lesson equipment: computer, interactive whiteboard, coil, tripod with foot, strip magnet – 2 pcs., demonstration galvanometer, wires, device for demonstrating Lenz’s rule.
During the classes
Start: 10.30
1. Organizational stage (5 minutes).
Hello guys! Today I will teach a physics lesson, my name is Innokenty Innokentyevich Malgarov, a physics teacher at the Kyllakh school. I am very glad to work with you, with the high school students, I hope today’s lesson will proceed in a productive manner. Today's lesson assesses attentiveness, independence, and resourcefulness. The motto of our lesson is “Everything is very simple, you just need to understand!” Now, your desk neighbors look at each other, wish them luck and shake hands. To establish feedback, I will sometimes clap my hands and you will repeat. Shall we check? Amazing!
Please look at the screen. What do we see? That's right, a waterfall and strong wind. What word (one!) unites these two natural phenomena? Yes, flow. Water flow and air flow. Today we will also talk about flow. Only about a flow of a completely different nature. Can you guess what? What are the topics you covered previously related to? That's right, with magnetism. Therefore, write down the topic of the lesson in your worksheets: Magnetic Flux. The phenomenon of electromagnetic induction.
Start: 10.35
2. Updating knowledge (5 minutes).
Exercise 1. Please look at the screen. What can you say about this drawing? The blanks in the worksheets should be filled in. Consult your partner.
1. A current-carrying conductor occurs around a magnetic field. It is always closed;
2. The strength characteristic of the magnetic field is magnetic induction vector 0 " style="border-collapse:collapse;border:none">
Look at the screen. By analogy, fill in the second column for the circuit in a magnetic field.
Please take a look at the demo table. On the table you see a stand with a movable rocker with two aluminum rings. One is whole, and the other has a slot. We know that aluminum does not exhibit magnetic properties. We begin to insert the magnet into the ring with the slot. Nothing happens. Now let's start introducing the magnet into the whole ring. Please note that the hundred ring begins to “run away” from the magnet. Stop the movement of the magnet. The ring also stops. Then we begin to carefully remove the magnet. The ring now begins to follow the magnet.
Try to explain what you saw (students try to explain).
Please look at the screen. There's a hint hidden here. (Students come to the conclusion that when the magnetic flux changes, an electric current can be obtained).
Task 4. It turns out that if you change the magnetic flux, you can get an electric current in the circuit. You already know how to change the flow. How? That's right, you can strengthen or weaken the magnetic field, change the area of the circuit itself and change the direction of the circuit plane. Now I will tell you a story. Listen carefully and complete task 4 at the same time.
In 1821, the English physicist Michael Faraday, inspired by the work of Oersted (the scientist who discovered the magnetic field around a current-carrying conductor), set himself the task of obtaining electricity from magnetism. For almost ten years he carried wires and magnets in his trouser pocket, unsuccessfully trying to generate an electric current from them. And one day, completely by accident, on August 28, 1831, he succeeded. (Prepare and show a demonstration). Faraday discovered that if a coil is quickly placed on a magnet (or removed from it), a short-term current arises in it, which can be detected using a galvanometer. This phenomenon came to be called electromagnetic induction.
This current is called induced current. We said that any electric current generates a magnetic field. Induction current also creates its own magnetic field. Moreover, this field interacts with the field of a permanent magnet.
Now, using the interactive whiteboard, determine the direction of the induction current. What conclusion can be drawn regarding the direction of the magnetic field of the induced current?
Start: 11.00
5. Application of knowledge in various situations (10 minutes).
I suggest you solve the tasks that are offered in the OGE in physics.
Task 5. A strip magnet is brought to a solid aluminum ring suspended on a silk thread at a constant speed (see figure). What will happen to the ring during this time?
1) the ring will remain at rest
2) the ring will be attracted to the magnet
3) the ring will be repelled by the magnet
4) the ring will begin to rotate around the thread
Task 6.
1) Only at 2.
2) Only in 1.
4) Only at 3.
Start: 11.10
5. Reflection (5 minutes).
It's time to evaluate the results of our lesson. What new have you learned? Have the goals set at the beginning of the lesson been achieved? What was difficult for you? What did you especially like? What feelings did you experience?
6. Information about homework
Find in your textbooks the topic “Magnetic flux”, “The phenomenon of electromagnetic induction”, read and see if you can answer the self-test questions.
Thank you again for your cooperation, for your interest and, in general, for a very interesting lesson. I wish to study physics well and, on its basis, to understand the structure of the world.
“It’s very simple, you just need to understand!”
Last name, first name of the student ________________________________________________ 9th grade student
Date "____"________________2016
WORKSHEET
Lesson topic:__________________________________________________________________________
__________________________________________________________________________
644 " style="width:483.25pt;border-collapse:collapse;border:none">
Task 4. Fill the gaps.
1. The phenomenon of the occurrence of current in a closed conductor (circuit) when the magnetic field penetrating this circuit changes is called _______________________;
2. The current that arises in the circuit is called ___________________________;
3. The magnetic field of the circuit created by the induction current will be directed __________________ the magnetic field of the permanent magnet (Lenz’s Rule).
https://pandia.ru/text/80/300/images/image006_55.jpg" align="left hspace=12" width="238" height="89"> Task 6. There are three identical metal rings. A magnet is removed from the first ring, a magnet is inserted into the second ring, and a stationary magnet is located in the third ring. In which ring does the induction current flow?
1) Only at 2.
2) Only in 1.
MBOU Lokotskaya secondary school No. 1 named after. P.A. Markova
Public lesson
on this topic
"Magnetic flux. Electromagnetic induction"
Teacher Golovneva Irina Aleksandrovna
Lesson type: combined
Lesson objectives:
Educational: study the physical features of the phenomenon of electromagnetic induction, formulate the concepts: electromagnetic induction, induced current, magnetic flux.
developing: to develop in students the ability to highlight the main and essential things in material presented in different ways, to develop the cognitive interests and abilities of schoolchildren in identifying the essence of processes.
educational : to cultivate hard work, a culture of behavior, accuracy and clarity in answering, and the ability to see the physics around you.
Lesson Objectives
Educational:
study the phenomenon of electromagnetic induction and the conditions for its occurrence;
consider the history of the issue of the connection between the magnetic field and the electric field;
show cause-and-effect relationships when observing the phenomenon of electromagnetic induction,
promote the actualization, consolidation and generalization of acquired knowledge, and the independent construction of new knowledge.
Educational: contribute to the development of the ability to work in a team, express one’s own judgments and argue one’s point of view.
Educational:
promote the development of students' cognitive interests;
promote the modeling of your own value system based on the idea of self-development.
Sequence of presentation of new material
Magnetic flux.
The history of the discovery of the phenomenon of electromagnetic induction.
Demonstration of Faraday's experiments on electromagnetic induction.
Practical application of the phenomenon of electromagnetic induction.
Equipment
Collapsible transformer, galvanometer, permanent magnet, rheostat, ammeter, magnetic needle, key, connecting wires, generator model, multimedia projector, audio recording, presentation on the topic.
Lesson plan.
1. Organizational moment.
2. Updating knowledge.
In previous lessons, we examined the magnetic field and the characteristics of the magnetic field, its effect on a conductor carrying current and on a moving charge.
1. What is the source of the magnetic field?
2.What physical quantity is a characteristic of a magnetic field?
3.What are the rules for determining the direction of the magnetic induction vector?
Today the topic of our lesson is “Magnetic flux. Discovery of the phenomenon of electromagnetic induction"
We have to consider the following questions:
1. Magnetic flux.
2. History of the discovery of the phenomenon of electromagnetic induction.
3. Demonstration of Faraday’s experiments on electromagnetic induction.
4. The significance of the discovery of the phenomenon of electromagnetic induction.
3. Learning new material
( Presentation slides, an interactive whiteboard, equipment for demonstrating experiments, and audio recordings are used).
1. Magnetic flux (definition, methods of change, dimension, formula). Repetition of 9th grade. Reinforcement using presentation slides.
1. The study of electromagnetic phenomena shows that there is always a magnetic field around an electric current. (Demonstration of Oersted's experience). Electric current and magnetic field are related to each other.
But if an electric current “creates” a magnetic field, then isn’t there an opposite phenomenon? Is it possible to “create” an electric current using a magnetic field? The English scientist M. Faraday set himself this task in 1821.
On the screen is a portrait of M. Faraday (1791 - 1867).
The teacher, against the background of music, introduces the life and work of Faraday.
Faraday worked on the task he set for himself for 10 years. He discovered electromagnetic induction, a new phenomenon that he studied in detail and described in a number of articles. Faraday's discovery was a new step in the study of electromagnetic phenomena.
2. To understand how Faraday managed to “transform magnetism into electricity,” let’s perform some of Faraday’s experiments using modern instruments. (Experiments are demonstrated and analyzed)
a) Faraday discovered that if you take two wire windings (we will take two coils) and change the current in one of them, for example, by closing or opening the circuit of the primary coil, then a current arises in the secondary coil, despite the fact that the coils are isolated from each other from friend. The phenomenon of exciting an electric current in a closed conductor using a magnetic field is called electromagnetic induction. The current excited in this way was called induction current.
I demonstrate my experiments:
The appearance of an induction current in a closed coil when the current in the second coil is turned on and off;
The appearance of an induction current in a closed coil when the current strength is changed using a rheostat in the second coil;
The appearance of an induction current when the coils move relative to each other.
We carry out an experiment with instruments: a coil connected to a galvanometer, a magnet.
Conclusion: in all the cases considered, the induced current arose when the magnetic flux penetrating the coil area covered by the conductor changed.
We make a drawing based on the experiments carried out. (Drawings on the board).
Consolidation of the studied material and control of knowledge.
Test work in progress
Reflection.
Students have emoticons on their desks (smiling, indifferent and sad). The teacher asks to hold up the one that best suited the mood of each student in the lesson.
Today we got acquainted with the phenomenon of electromagnetic induction, which is used in all modern generators that convert mechanical energy into electrical energy. This phenomenon, discovered by M. Faraday in 1831, played a decisive role in the technical progress of modern society. It is the physical basis of modern electrical engineering, providing industry, transport, communications, agriculture, construction and other sectors, and people’s everyday life with electrical energy.
Thank you everyone for your active work in class. Ratings.
Homework
§ 8, 9 No. 838 (Rymkevich)
Application
Exercise. Read the biography of M. Faraday and fill out the table reflecting the scientist’s contribution to the discovery of the phenomenon of electromagnetic induction. Use textbooks, encyclopedias, books, electronic publications, Internet resources, and other sources.
| Last name, first name, years of life | Photograph or pictorial portrait | Countries in which he worked | Main contribution into science | Opening symbol or a drawing of the installation on which the scientist worked |
| Contributions to other branches of physics |
||||
| What struck you most about the biography? |
||||
Lesson topic:
Discovery of electromagnetic induction. Magnetic flux.
Target: To familiarize students with the phenomenon of electromagnetic induction.
During the classes
I. Organizational moment
II. Updating knowledge.
1. Frontal survey.
- What is Ampere's hypothesis?
- What is magnetic permeability?
- What substances are called para- and diamagnetic?
- What are ferrites?
- Where are ferrites used?
- How do we know that there is a magnetic field around the Earth?
- Where are the Earth's North and South magnetic poles?
- What processes occur in the Earth's magnetosphere?
- What is the reason for the existence of a magnetic field near the Earth?
2. Analysis of experiments.
Experiment 1
The magnetic needle on the stand was brought to the lower and then to the upper end of the tripod. Why does the arrow turn to the lower end of the tripod from either side with the south pole, and to the upper end with the north end?(All iron objects are in the Earth's magnetic field. Under the influence of this field, they are magnetized, with the lower part of the object detecting the north magnetic pole, and the upper part detecting the south.)
Experiment 2
In a large cork plug, make a small groove for a piece of wire. Place the cork in water, and place the wire on top, placing it parallel. In this case, the wire together with the plug is rotated and installed along the meridian. Why?(The wire has been magnetized and is installed in the Earth's field like a magnetic needle.)
III. Learning new material
Magnetic forces act between moving electric charges. Magnetic interactions are described based on the idea of a magnetic field that exists around moving electric charges. Electric and magnetic fields are generated by the same sources - electric charges. It can be assumed that there is a connection between them.
In 1831, M. Faraday confirmed this experimentally. He discovered the phenomenon of electromagnetic induction (slides 1,2).
Experiment 1
We connect the galvanometer to the coil, and we will extend a permanent magnet from it. We observe the deflection of the galvanometer needle, a current (induction) has appeared (slide 3).
Current in a conductor occurs when the conductor is in the area of action of an alternating magnetic field (slide 4-7).
Faraday represented an alternating magnetic field as a change in the number of lines of force penetrating the surface limited by a given contour. This number depends on induction IN magnetic field, from the area of the circuit S and its orientation in a given field.
Ф=BS cos a - magnetic flux.
F [Wb] Weber (slide 8)
The induced current can have different directions, which depend on whether the magnetic flux passing through the circuit decreases or increases. The rule for determining the direction of the induction current was formulated in 1833. E. X. Lentz.
Experiment 2
We slide a permanent magnet into a lightweight aluminum ring. The ring is repelled from it, and when extended, it is attracted to the magnet.
The result does not depend on the polarity of the magnet. Repulsion and attraction are explained by the appearance of an induction current in it.
When a magnet is pushed in, the magnetic flux through the ring increases: the repulsion of the ring shows that the induced current in it has a direction in which the induction vector of its magnetic field is opposite in direction to the induction vector of the external magnetic field.
Lenz's rule:
The induced current always has a direction such that its magnetic field prevents any changes in the magnetic flux that cause the appearance of the induced current(slide 9).
IV. Conducting laboratory work
Laboratory work on the topic “Experimental verification of Lenz’s rule”
Devices and materials:milliammeter, coil-coil, arc-shaped magnet.
Progress
- Prepare a table.
Lesson summary on the topic:
"Magnetic field induction".
The purpose of the lesson: introduce the concept of magnetic field induction in accordance with the answer plan about a physical quantity.
Educational objectives of the lesson:
- form a correct understanding of the magnetic induction vector as a force characteristic of the magnetic field;
- enter the unit of magnetic induction;
- form a correct idea of the direction of magnetic induction and a graphical representation of magnetic fields.
Developmental objectives of the lesson:
- establish the relationship between theory and experiment when studying phenomena;
- further development of skills and abilities to analyze and draw conclusions;
- maintain interest in the subject when conducting experiments.
Educational objectives of the lesson:
- nurturing a sense of sociability, goodwill and the ability to listen to each other.
Skills acquired by students:compare the results of experiments, observe, analyze, generalize and draw conclusions, explain physical phenomena, solve problems, develop oral speech.
Hardware and software training tools:interactive whiteboard, personal computer, multimedia projector, Microsoft Power Point presentation program, presentation “Magnetic field induction”, video fragments “Earth’s magnetic field”, “Magnetic storms”.
Equipment: worksheets, strip and arc magnets, conductors, current source, key, tripod, iron filings.
During the classes:
1. Organizational moment.
2. Posing the question using the video fragment “Earth’s Magnetic Field.”
The power of modern science amazes even the inexperienced mind: it has split the atomic nucleus, reached the far corners of the Universe, and discovered the laws of the universe. But whether we like it or not, the future fate of humanity depends on the magnetic interaction of the Sun and the Earth.
Show a video clip. Issues discussed:
- What is the reason for the existence of the Earth's magnetic field?
- How does the Sun affect the Earth?
- What is the role of the Earth's magnetic field in interaction with the Sun?
Today, every person should have a competent understanding of the essence of the physical processes on which his life depends.
3. Comprehensive testing of students' knowledge.So, let's systematize the knowledge that we have on the topic: “Magnetic field”.
“The thinking mind does not feel happy until it succeeds in connecting together the disparate facts that it observes.” Hevesi.
Frontal survey + individual responses to describe and demonstrate classic experiments on this topic.
- What is a magnetic field?
- What generates a magnetic field?
- Who first discovered the magnetic field around a current-carrying conductor?
- Demonstrate Oersted's experience.
- How is a magnetic field represented graphically?
- How to obtain a picture of magnetic lines using iron filings? Show this through experience.
- What are the magnetic lines of a straight conductor, a solenoid and a permanent magnet?
- How can we experimentally detect the presence of a force acting on a current-carrying conductor in a magnetic field?
- How to determine the direction of this force?
- Formulate the left-hand rule.
4.Checking homework. Exercise 36.
5.Updating knowledge.
What do you think determines how strong the interaction between a permanent magnet and a conductor with current will be? What are your guesses?
“Without a doubt, all our knowledge begins with experience.” (Immanuel Kant).Test it by experience.
Experience: Find out which of the magnets offered to you has a stronger effect on iron objects.
Thus, it is necessary to introduce a value that would characterize the magnetic field and show with what force it acts on a current-carrying conductor, iron objects and moving charged particles. This quantity is called magnetic field induction.
Lesson objectives: characterize the magnetic field induction according to the plan:
- Determination of physical quantity;
- Symbol;
- Calculation formula;
- Direction;
- Units.
6.Explanation of new material.As the lesson progresses, the children fill out worksheets and, as a result, receive a basic outline on this topic.
Experience: interaction of a permanent arc-shaped magnet and a conductor with current.
Goal: find out what determines the strength of interaction?
Conclusion: magnetic strength interaction depends on the magnetic field, current strength and length of the conductor.
F/IL=const B=F/IL B - magnetic induction
Conclusion: Magnetic induction is the power characteristic of a magnet. fields. The greater the magnetic induction module at a given point, the greater the force the field will act on a current-carrying conductor or a moving charge.
Magnetic induction is a force characteristic of a magnetic field, the modulus of which is equal to the ratio of the modulus of the force with which the field acts on a magnet located perpendicularly. lines of a conductor with current, to the strength of the current and the length of the conductor.
Units of measurement: 1T=1N/A*m, tesla. The units of measurement are named after the Serbian electrical engineer Nikola Tesla, whose photo is presented on the slide.
Magnetic induction is a vector quantity.Conclusion: It is directed tangentially to the magnetic lines.Let me remind you that the direction of magnetic lines is determined by the right-hand rule.Magnetic direction induction indicates the north pole of the magnetic needle.Then a more precise definition of magnetic lines can be given as follows: these are lines at each point of which the tangents coincide with the magnetic induction vector.
Since a magnetic field arises around current-carrying conductors of different configurations, despite the fact that magnetic lines are always closed, they can have different configurations. Therefore, magnetic fields are classified into homogeneous and inhomogeneous. Magnetic lines of uniform fields are located at the same distance from each other and have the same direction. In the pictures indicate the magnetic vectors. induction, noting that they too must have the same direction and the same length.
Conclusion: A magnetic field is called uniform if at all its points the magnetic induction is the same in magnitude and direction.
7.Checking students' understanding of new knowledge.
Answer the questions:
- What is the force characteristic of a magnetic field called?
- How is it designated?
- What formula is used to calculate the magnetic induction module?
- Can we say that mag. induction depends on the strength with which the magnet. does the field act on a current-carrying conductor, current strength, conductor length?
- What is the unit of magnetic induction called?
- Using the pictures in the textbook 120,121,122 (p. 159), determine which fields are homogeneous and which are not.
- Is the Earth's magnetic field uniform?
8. Consolidation of student knowledge
Run a practice test:
Option 1:
1. When electric charges are at rest, then around them... is detected.
2.How are iron filings located in a direct current magnetic field?
A. randomly B. in circles surrounding the conductor
3.Which pole of the magnetic needle indicates the direction of the magnetic induction vector?
A. northern B. southern
A.yes B.no
5.What determines the force with which a magnetic field acts on a current-carrying conductor?
A. cross-sectional area of the conductor
B. magnetic induction
V.current
G. time of exposure of the magnetic field to the conductor
D. length of conductor
Option 2:
1.When electric charges move, there is(are) around them
A. electric field B. magnetic field
B.electric and magnetic fields
2.What are the magnetic lines of a current-carrying coil?
A. closed curves B. straight lines
B. randomly located lines
3. In what units is magnetic field induction measured?
A. Newton B. Ampere V. Tesla
4.Is the magnetic field shown in the figure uniform?
A.yes B.no
5.What is the direction of the magnetic induction vector?
A. tangent to the magnetic lines B. tangent to the current-carrying conductor
Check your desk neighbor: Option 1: 1-A,2-B,3-A,4-A,5-BVD
Option 2: 1-B,2-A,3-B,4-B,5-A
9.Homework:§46, orally answer the questions after paragraph, exercise: 37 (in writing).
10. Lesson summary.
- What new things have you learned? What have you learned?
- What did you find particularly difficult?
- Which material aroused the most interest?
A stream of charged particles flying from the Sun reaches the Earth in 8 minutes. This leads to changes in the Earth's magnetic field, to so-called magnetic storms. At this point, people experience a sharp jump in blood pressure. On the day of a solar flare, the number of cardiovascular diseases increases. There are even changes in the blood. Blood contains positive and negative ions, and the magnetic field acts on charged particles. Variable Magn. the field disorients the charged particles of the blood, increasing its sluggishness.
Muscle loads, physical education and sports will help you adapt to unfavorable environmental changes. There is an improvement in blood circulation, oxygen supply to all organs, and an increase in the body’s resistance to changes in the Earth’s magnetosphere.
One philosopher was asked: “What is the most important thing in life: wealth or fame?” The sage replied: “Neither wealth nor fame makes a person happy. Health is one of the most important sources of happiness and joy.” I wish the same for you!
