Lesson on the topic of elementary particle physics. Methodological development of the lesson "three stages in the development of elementary particle physics." Atomic and nuclear physics

Kaptelova N.V., physics teacher, Municipal Educational Institution “Gymnasium No. 79”, Barnaul, Altai Territory

Grade 11

Lesson on the topic “Elementary particles” (2 hours).

Level – basic

Class profile – humanitarian

Text used - § 64 “Elementary particles” (Mansurov A.N., Mansurov N.A., textbook “Physics-10-11” for humanitarian schools)

Technology “Development of Critical Thinking through Reading and Writing” (RDMCHP)

Lesson type: working with informational text

Goals:

didactic – through indirect study of the text, to form a system in students scientific knowledge about elementary particles Oh

developmental – to develop among schoolchildren methods of effective processing educational information, continue to develop a method of independent learning, cognitive and communicative competencies

educational – to continue to develop students’ confidence in their own cognitive abilities and a dialectical-materialistic worldview

methodological - to create conditions for students to master the method of independent learning based on the RKMChP technology

Expected Result:

students’ assimilation of the system of scientific knowledge about elementary particles and its presentation in the form of a cluster;

obtaining and understanding by each student his own experience of independent cognitive activity based on working with text through individual, pair, group, collective forms of work (RKMChP technology).

Note: Cluster - a graphical method that allows you to present information in a structured and systematized form, to identify the keywords of the topic. A cluster is a graphical diagram consisting of ovals. In the center of the cluster, in the main oval, is the main problem, theme, idea. In the ovals of the next level - classifying features or grounds for systematization, in the ovals of the third level - further detail, etc. Clusters can be very extensive, so you always need to choose the level of detail at which you can stop. Using clusters, large amounts of information can be presented in a systematic way.

The cluster contains keywords key ideas indicating logical connections between text subjects. Connections give the picture integrity and clarity.

The cluster (like all graphical diagrams) is a model of the topic being studied, allowing you to see the topic as a whole, “from a bird’s eye view.” Motivation increases, because The ideas of the topic are more easily perceived. A person always needs graphic images. The brain remembers patterns. Presentation of information by students in the form of a cluster contributes to its creative processing, therefore ensuring the assimilation of information at the level of understanding. Clusters (like other schemes) allow you to “boost” your thinking, make it more flexible, get rid of stereotypes, and turn dogmatic thinking into critical thinking.

It is also important that the construction of clusters allows us to identify the system keywords, which can be used to search the Internet, as well as to determine the main areas of student research and select topics for educational projects.

Homework(extracurricular activities):

1. § 65 (independently using RKMChP technology)

2. Clusters made using ICT

(2 and 3 optional)

Lesson script.

Call.

Stage goals:

Encouragement to work with new information, awakening interest in the topic

- calling existing knowledge on a topic to the surface

- conflict-free exchange of opinions

"Suggestive questions"

"Cluster"

2. Students are given questions to think about and discuss:

Exit to the logical chain: nature-body-matter-molecule-atom-nucleus-nucleons (proton, neutron)-electron.

Remember what elementary particles you know? Think of it as a cluster.

(Proton, neutron, electron, photon, π-meson)

Students work individually in notebooks, then in pairs, according to their suggestions, the teacher draws up a cluster on the board. One of the clusters proposed by students:

Can such a number of them claim to be the “first bricks of the Universe”, truly elementary particles?

Comprehension

Stage goals:

Gaining new knowledge

Development different types reading: introductory, studying, assimilating, searching, techniques for comprehending information text

Development of analytical, discussion, communication skills

"I.N.S.E.R.T. System"

"Cluster"

“Think on your own/in pairs/in a group”

Independent work with text

Perception of information. At this stage the student works individually(“Think on one's own"). Introductory reading, receipt general idea on the topic of the text.

Study reading. Individual work (“Think for yourself”). Operations of semantic perception of text elements, understanding words, sentences, paragraphs, isolating text subjects (main concepts, keywords, ideas), identifying connections (logical, cause-and-effect, spatial, temporal, etc.) of text subjects. Understanding the connection between the content of a given text and the content of other studied texts, interpreting a given text based on this connection. The use of text marking I.N.S.E.R.T. helps to understand the content: (I.N.S.E.R.T. - “Interactive Notation System for Enhanced Reading and Thinking”)

- “known”

- - “contradicts ideas”

+ - “interesting and unexpected”

? - “learn more”

! - "important"

Assimilation reading. Checking your understanding of the text. Students in pairs(“Think in pairs”) are spoken in your own words answer each other questions about the text.

Processing information. Individual work (“Think for yourself”). Breaking information down into related parts. Identification of the grounds for systematization and classification of the information received.

Synthesis of processed information. Individual work (“Think for yourself”). Grouping, combining information, creating a cluster. Translation of the received information “into another language”: from the language of words to the language of diagrams, from verbal language to graphic.

Presentation and protection of individual clusters in pairs(“Think in pairs”), then in groups(“Think Together”)

“Reverse translation” of information: from the language of diagrams to the language of words, from graphic language to verbal, and the information is communicated in one’s own words. Exchange of ideas in discussion or debate. Argumentation, constructive criticism, clarification, joint finalization of the cluster.

Reflection

Reflect on the meaning of what has been covered;

Look at the content of the lesson in the light of your own life experience

"Return to the Cluster"

"Exit card"

Presenting and defending several options for group clusters in front of the class, collective discussion.

Proposed final cluster option:

2. Task: Compare this cluster with the cluster proposed at the beginning of the lesson. (!!!)

Find a place on it for an electron, proton, neutron, photon, π-meson.

Draw a conclusion. ( Significant increase in knowledge about elementary particles!)

3. (Summarizing and motivation for further cognitive activity). Let's return to the questions with which we started the lesson. Have you found any answers to them? What questions remain unanswered? What new ones have emerged? Where to look for answers?

What does the world around us consist of?

Does the structure of matter resemble an endless series of nested dolls, or does the division process stop when an indivisible elementary particle is discovered?

What are the most primordial fundamental particles from which all others are made?

Is there such a level of organization of matter in nature that there is nothing deeper than that?

Can such a number (more than 400) claim to be the “first bricks of the Universe,” truly elementary particles?

How to navigate in such an abundance of elementary particles?

Which particles are truly “elementary”?

(Think on your own/in pairs/group). Discussion.

Individual paperwork(10 min) “Exit card” - 1) the most important idea of the lesson; 2) one question on the topic of the lesson 3) general comment on the lesson material

Do a self-assessment of your work in class (satisfied with yourself, not very happy, not happy, why?).

IV. Homework (extracurricular work)

Give students the opportunity to conduct independent work to deepen the knowledge acquired during the lesson;

Practice the skill of independent learning activities;

Develop Creative skills schoolchildren

1.Study § 65 (independently using the RKMChP technology)

2. Clusters to § 65, made using ICT

3. Creative work on a topic of interest.

(2 and 3 optional)

Observations of students show that the construction of clusters is perceived by them as creative work , where it is possible to implement your own vision of the problem, your own approach, variability, how means self-realization, self-affirmation.

The possibility of individual, pair, group and collective work creates psychological comfort educational process. Including each student in three types

activity (thinking, writing, speaking) provides “internal information processing.” These factors contribute to students’ assimilation of new material at the level of understanding, comprehension and the development of their educational-cognitive motivation and activity (especially for those students who do not fit well into the system of traditional, illustrative and explanatory teaching). And most importantly - they practically master a way to independently acquire new knowledge, they develop functional literacy.

The above-described teaching technology based on creative text processing allows you to teach interesting, fast, high quality and gives students a sense of satisfaction.

Examples of performing clusters on the topics “Fundamental interactions” and “Fundamental particles”:

Goal: To tell students about elementary particles, their basic properties and classifications

During the classes

New material (given in lecture)

Studies of the structure of the atom and the atomic nucleus have shown that the composition of the atom includes electrons, protons, and neutrons. It was customary to call these particles elementary. Photon (), positron (e +) and neutrino (v), which are directly related to the atom and nucleus, also began to be called elementary particles.

According to the original plan, elementary particles are the simplest particles from which the substance (atoms) of the existing world is built.

Elementary particles were initially imagined as something eternal, unchanging, indestructible, and the image of an elementary particle was associated with the image of a grain of sand or a structureless small ball.

Nowadays there is no clear criterion for elementaryness. The concept of "elementary particle" is very complex these days.

Let us briefly list the known elementary particles in the order of their historical discovery.

Methodological notes: Students are asked to fill out the following table at the time of further explanation (Annex 1)

What type does it belong to?	Particle name	Designation	Opening year	Charge q	Particle mass

The electron was discovered by J.J. Thomsan in 1897. The masses of other elementary particles are usually expressed through the mass of the electron.

In 1900 M. Planck and especially, in 19005. A. Einstein showed that light consists of separate portions - photons. A photon has no charge, and its rest mass = 0. A photon can only exist in the process of moving at the speed of light.

Rutherford's experiments on particle scattering in 1911. Led to the discovery of the proton. Proton mass=1836m e

Most physicists were confident that they had finally managed to reduce the entire diversity of chemical elements and substances of nature to two simple entities: electrons and protons. The picture drawn by the physicists of those years on the structure of matter instilled a sense of scientific beauty and grace. In the period from 1911 By 1932 Many scientists were filled with a sense of satisfaction that they were able to fulfill the centuries-old dream of scientific research.

However, in 1928 P. Dirac, and subsequently in 1932 K. Anderson discovered such particles, called positrons(e+)

The positron is the first elementary particle predicted theoretically.

In 1932 D. Chadwig discovered a neutron with mass = 1838 m e

A neutron in a free state, unlike a proton, is unstable and decays into a proton and an electron with a half-life T = 1.01 10 3 s. Inside the nucleus, a neutron can exist indefinitely.

In 1931-1933. W. Pauli, analyzing -decay, suggested that during decay, in addition to the proton and electron, another neutral particle with rest mass = 0 is emitted. This particle was called neutrino()

Only in 1956 K. Cowan and his colleagues discovered an antineutrino() produced in a nuclear reactor. It was “caught” when studying the reaction: p+ v n+e + , the neutrino causes the reaction n+p+e - .

In 1937 K. Anderson and S. Nedderman discovered charged particles with a mass of 206.7m e, these particles were called -mesons (+ and -), having a charge of +e and -e. Currently, these particles are called -particles or -muons.

In 1947 English scientists S. Powell, G. Occhialini and others discovered -mesons (-meson is the primary meson, which, when decaying, gives muons)

The meson has a charge of +e and -e, and a mass of 273.2 m e. Somewhat later than 1950, a neutral -meson (o) was discovered, with a mass of 264.2 m e. Currently, three types of -meson are known: -, o, + , they interact intensively with nucleons and are easily created when nucleons collide with nuclei, i.e. are nuclear active. It is currently believed that -mesons are nuclear field quanta responsible for the bulk of nuclear forces.

From 1949-1950 A literal “invasion” of elementary particles began, their number rapidly increasing.

The newly appeared particles can be divided into two groups:

The first group includes particles with masses of about 966 m e and 974 m e, currently called K-mesons. K + and K - mesons are known with masses of approximately 966.3 m e and electric charges +e and -e. Neutral K-mesons (K o and K o) with masses of 974.5 m e are known.

The second group of particles is called hyperons. The following hyperons are currently known:

In 1955 The antiproton was discovered, and in 1956 the antineutron was discovered.

Behind last years new quasiparticles (resonance states) with an unusually short lifetime were discovered, on the order of 10 -22 - 10 -23 sec. In this case, it is not even possible to record traces of particles and their existence can be judged only from indirect considerations, from an analysis of the behavior of their decay.

In recent years, a second type of neutrino has been discovered, the so-called muon neutrino (antineutrino) and, which is emitted, for example, during the decay of -mesons;

III group- heavy particles, or baryons

This group includes:

Nucleons and their antiparticles
Hyperons and their antiparticles

Application of thermonuclear energy using the example of the Tokamak installation

Students are asked to answer the questions:

What nuclear reaction is called thermonuclear? (oral)
How can it be done thermonuclear reaction?
Explain the principle of operation of the Tokamak installation. (in writing, using additional literature)
Explain the principle of operation of a laser installation for thermonuclear fusion" (in writing using additional literature)

Lesson outline

on this topic

"The concept

about elementary particles"

(Grade 11)

Physics teacher

Cherpita Valery Nikolaevich

GBOU School 2051

Moscow cities

The concept of elementary particles.

Classification of elementary particles.

/data/files/u1514922328.pptx (Presentation for the lesson on the topic “The concept of element particles”)

Lesson objectives: to acquaint students with elementary particles as the only representatives of matter at a level less than 10¯ ¹⁵ m spatial dimensions and distances; to uncover general properties elementary particles, give their classification.

Lesson Plan

Lesson steps	Time, min	Methods and techniques
Introduction: setting educational problems for the lesson	3 - 5	Teacher's story and formulation
Studying new material: the concept of elementary particles, classification of particles, quarks, etc.	30 - 35	Teacher's story using conversation elements. Working with the textbook. Textbook material. Table. Notebook entries
Summing up, highlighting the main thing. Homework	5 - 7	Conversation on issues. Formulation of conclusions

1. Throughout the physics course, students encountered elementary particles more than once. Already at the first stage electrons were studied; further the concept of electron was used in many cases. In quantum physics, students learned about the proton and neutron.

Final lessons can be conducted in the form of school lectures, including elements of conversation and short presentations by students on individual issues. To maintain the cognitive activity of students in the lesson, it is necessary to ensure a change in their activity, to combine informational material (story, message) with reproductive material (answers to questions, independent work with a textbook) and problematic (posing a problem, putting forward hypotheses, etc.). When preparing lessons, you should take care of visual aids, prepare tables, photographs of tracks, etc. There is no longer time in the course for repeated application of introduced concepts, so it is necessary to connect the new with the previously learned as much as possible.

2. Presentation of new material.As science delved deeper into the structure of matter, it discovered molecules, atoms, found out that an atom consists of a nucleus and electrons, and finally established complex structure nucleus, which contains protons and neutrons.

If we consider the structure of matter taking into account this information, then in the microcosm at the level of small distances, about 10¯¹⁴ - 10¯¹⁵ m, we can conclude that matter consists of protons, neutrons and electrons. But matter is represented in nature not only by matter, but also by an electromagnetic field. The electromagnetic field also consists of microparticles - photons.

Microparticles - photons, electrons, protons, neutrons - are called elementary particles. The word “elementary” means the simplest element underlying matter: all material objects - bodies, fields - consist of these particles. When this term was introduced, it was assumed that elementary particles had no internal structure, i.e. they no longer consist of anything. Now the concept of elementaryity has been clarified, as will be discussed below.

Currently, more than 400 microparticles have been discovered, similar in size, mass, electric charge (and some other properties) to those listed above. All of them are also called elementary.

Feature most elementary particles - theirinstability. All particles, except photons in the void, electrons, protons, neutrons (in the nucleus) and neutrino particles, decay spontaneously, eventually becoming stable. These processes are similar to the radioactive decay of nuclei. Average lifetime of unstable elementary particles; particles whose lifetime are extremely short-lived or relatively stable are considered to be10 ¯ ⁶ - 10 ¯ ¹⁴ s, athere are also particles that live only10 ¯ ²² - 10 ¯ ²³ With.

A neutron outside the nucleus is also unstable: its average lifetime is 16 minutes, but compared to the lifetime of short-lived particles this is a very long time.

It is clear that if the Universe once arose, then during its existence to the present day all unstable elementary particles would have decayed, turned into stable ones or disappeared, giving up their energy to the thermal motion of stable particles of matter. Where do short-lived particles come from? They were discovered and obtained both in nuclear reactions and in various reactions with stable elementary particles. A reaction occurs when one elementary particle collides with another or spontaneously disintegrates. As a result of the reaction, new particles are formed, and the mutual transformation of particles occurs.

As an example of a decomposition reaction, we give the following reaction:

n → p + e¯+ ṽ ,

where a neutron decays into a proton, electron and antineutrino.

Antineutrinos and neutrinos are particles with a very low rest mass, thousands of times smaller than the lightest particle - the electron. They are electrically neutral. Neutrino is a stable particle. For a long time, after the theoretical prediction, the actions of neutrinos could not be recorded experimentally. Finally, in 1956, the reaction was carried out

p + ṽ → n + e˖

in which a neutron and a positively charged electron - a positron - were formed.

A positron is discovered in experience when it encounters an electron; it “disappears” along with the electron:

e˖ + e¯ → 2y

The reaction is calledannihilationelectron-positive pair; As a result, two photons are formed, which are recorded by special counters.

Mutual convertibilityelementaryparticles during interactions is their second feature.

The third feature inherent in all elementary particles isEach particle has a twin - an antiparticle.If a particle is electrically charged, then the antiparticle carries a charge of the opposite sign. But uncharged particles also have antiparticles. When they meet, the interaction between a particle and an antiparticle leads to their annihilation, i.e. to disappearance, to transformation into photons or other particles. Currently, antiparticles have been discovered for almost all known particles, including the antiproton and antineutron. Even an atom consisting of antiparticles, antihelium, has been obtained, so in principle we can talk about the possibility of the existence of antimatter. The combination of matter with antimatter should lead to the transition of matter into a field, to the annihilation of matter within the framework of the laws of conservation of energy, momentum, and electric charge; this releases energy equivalent to rest massmc². But it is now known that the Universe consists only of matter, and there is no antimatter in it, just as there are no or very few stable antiparticles.

Next you should giveclassification of elementary particleswith the division of all particles by mass into classes: leptons, mesons, baryons. When considering and analyzing the table of elementary particles, we pay attention to their characteristics: masses, charges, lifetime. We inform you that the table contains the main particles - stable and relatively stable. Many unstable particles - mesons and baryons, calledresonances, - not included in the table.

Let's discuss particle sizes. According to modern data, photons and leptons do not exhibit extension or internal structure in experiments. In this respect, they can be classified as truly elementary (primary) particles. Mesons and baryons have sizes of the order of 10¯ ¹⁵ m. Experiments on the scattering of very high-energy electrons by them, similar to Rutherford’s experiments, lead to the conclusion about the presence of an internal structure of mesons and baryons. We can say that they are not elementary, but consist of subelementary particles calledquarks.

When studying elementary particles, we do not touch upon the second macroscopic field that exists in nature—gravitational field. It has been theoretically established that at the microlevel it consists of field quanta calledgravitons. These, like photons, are particles without rest mass and charge. However, graviton has not been experimentally detected.

3. Summing up. Reflection

Homework

World of elementary particles

Lesson in 11th grade

The purpose of the lesson:

Educational:

To acquaint students with the structure of elementary particles, with the features of forces and interactions inside the nucleus; learn to summarize and analyze acquired knowledge, to correctly express your thoughts; promote the development of thinking, the ability to structure information; cultivate emotional and value-based attitudes towards the world

Educational:

Continue to develop thinking, the ability to analyze, compare, and draw logical conclusions.

Develop curiosity, ability to apply knowledge and experience in different situations.

Educational:

Development of intellectual teamwork skills; education of the foundations of moral self-awareness (thought: the responsibility of a scientist, a discoverer for the fruits of his discoveries);

To awaken students’ interest in popular science literature and in studying the prerequisites for the discovery of specific phenomena.

The purpose of the lesson:

Create conditions for the development of intellectual and communicative competencies in which the student will be able to:

Name the main types of elementary particles;

Understand the ambiguity of the modern standard model of the world;

Formulate your ideas about the history of the development of elementary particles;

Analyze the role of development elementary physics;

Classify elementary particles according to their composition;

Think about the need to have your own position, to be tolerant of another point of view;

Demonstrate conflict-free communication when working in a group.

Lesson type: learning new material.

Lesson format: combined lesson.

Lesson methods: verbal, visual, practical.

Equipment: computer presentation, multimedia projector, workbook student, personal computer.

Lesson steps	Time, min.	Methods and techniques
1.Organizational introduction. Statement of educational problem.		Record the topic of the lesson. Teacher's story.
2. Updating knowledge (student presentation)		The student’s story about existing knowledge, the prerequisites for learning new things.
3. Learning new material (teacher presentation)		Teacher's story using slides. Observation. Conversation. Student story using slides.
4. Practicing the studied material. Consolidation.		Consolidation according to the supporting notes and working with the textbook. Answers to security questions.
5. Summing up. Homework		Identification of the main thing by the teacher and students.

During the classes

Organizing time lesson(greeting, checking students’ readiness for the lesson)

Today in the lesson we will look at different views on the structure of the world, what particles everything that surrounds us consists of. The lesson will be lecture-like and mostly requires your attention.

At the beginning of the lesson, I want to bring to your attention the history of the origin of the doctrine of particles.

2. Updating knowledge. (Presentation by Aleksakhina V. “History of the development of knowledge about particles”)

Slide 2. Ancient atomism- these are ideas about the structure of the world by ancient scientists. According to Democritus, atoms were eternal, unchanging, indivisible, particles differing in shape and size, which, when united and separated, formed different bodies.

Slide 3. Thanks to the discovery by scientists Dirac, Galileo and Newton of the principle of relativity, the laws of dynamics, the laws of conservation, the law universal gravity, in the 17th century, the atomism of the ancients underwent significant changes and became established in science mechanical picture of the world, which was based on gravitational interaction - all bodies and particles are subject to it, regardless of charge.

Slide 4. The knowledge accumulated in the study of electrical, magnetic and optical phenomena has led to the need to supplement and develop the picture of the world. Thus, in the 19th century and until the beginning of the 20th century, electrodynamic picture of the world. It already considered two types of interaction - gravitational and electromagnetic. But they failed to explain only thermal radiation, the stability of the atom, radioactivity, the photoelectric effect, line spectrum.

Slide 5. At the beginning of the 20th century, the idea of energy quantization appeared, which was supported by Planck, Einstein, Bohr, Stoletov, as well as the wave-particle dualism of Louis de Broglie. These discoveries marked the emergence quantum field picture of the world, in which strong interaction was also added. The active development of elementary particle physics began.

3. Learning new material

Until the thirties of the 20th century, the structure of the world seemed to scientists in the most in simple form. They believed that the “complete set” of particles that make up all matter is the proton, neutron and electron. That's why they were called elementary. These particles also include the photon, the carrier of electromagnetic interactions.

Slide 6.Modern Standard World Model:

Matter consists of quarks, leptons and particles - carriers of interaction.

For all elementary particles there is a possibility of detecting antiparticles.

Wave-particle duality. Principles of uncertainty and quantization.

Strong, electromagnetic and weak interactions are described by grand unified theories. Ununited gravity remains.

Slide 7. The nucleus of an atom is made up of hadrons, which are made up of quarks. Hadrons are particles participating in strong interactions.

Classification of hadrons: Mesons consist of one quark and one antiquark Baryons consist of three quarks - nucleons (protons and neutrons) and

hyperons.

Slide 8. Quarks are the fundamental particles that make up hadrons. Currently, 6 different varieties (more often called flavors) of quarks are known. Quarks hold the strong interaction and participate in strong, weak and electromagnetic interactions. They exchange gluons, particles with zero mass and zero charge, with each other. For all quarks there are antiquarks . They cannot be observed in free form. They have a fractional electric charge: +2/3е - called U-quarks (top) and -1/3е - d-quark (bottom).

The quark composition of an electron is uud, the quark composition of a proton is udd.

Slide 9. Particles that are not part of the nucleus are leptons. Leptons are fundamental particles that do not participate in strong interactions. Today, 6 leptons and 6 of their antiparticles are known.

All particles have anticysts. Leptons and their antiparticles: electron and positron with them, electron neutrino and antineutrino. Muon and antimuon with them muon neutrino and antineutrino. Taon and antitaon - taon neutrino and antineutrino.

Slide 10. All interactions in nature are manifestations of four types fundamental interactions between fundamental particles - leptons and quarks.

Strong interaction Quarks are susceptible, and gluons are its carriers. It binds them together to form protons, neutrons and other particles. It indirectly affects the bonding of protons in atomic nuclei.

Electromagnetic interaction charged particles are susceptible. In this case, under the influence of electromagnetic forces, the particles themselves do not change, but only acquire the property of repelling in the case of charges of the same name.

Weak interaction Quarks and leptons are susceptible. The most famous effect of the weak interaction is the transformation of a down quark into an up quark, which in turn causes a neutron to decay into a proton, electron and antineutrino.

One of the most significant types of weak interaction is Higgs interaction. According to assumptions, the Higgs field (gray background) fills the entire space with liquid, limiting the range of weak interactions. The Higgs boson also interacts with quarks and leptons, ensuring the existence of their mass.

Gravitational interaction. It is the weakest known. All particles and carriers of all types of interactions, without exception, participate in it. It is carried out thanks to the exchange of gravitons - the only particles that have not yet been experimentally discovered. Gravitational interaction is always an attraction.

Slide 11. Many physicists hope that, just as they managed to combine the electromagnetic and weak interactions into the electroweak force, they will eventually be able to build a theory that unifies all known species interactions, the name of which is “Great Unification”.

4 . Consolidation of knowledge.

Primary consolidation(Presentation by Gordienko Zh. “Large Hadron Collider”. Modern scientists are trying to improve the process of studying particles in order to achieve new discoveries for scientific and technological progress. For this purpose, grandiose research centers and accelerators. One of these grandiose structures is the Large Hadron Collider.

Final consolidation(work in groups: answers to questions from the textbook)

You are divided into two groups: 1st row and 2nd row. You have a task on pieces of paper: you need to answer questions, and you will find the answers in the textbook in paragraph 28 (pp. 196 – 198).

First group tasks:

How many fundamental particles are there in total? (48)

Quark composition of an electron? (uud)

List the two strongest forces (strong and electromagnetic)

Total number of gluons? (8)

Second group tasks:

How many particles are at the heart of the universe? (61)

Quark composition of the proton? (udd)

List the two weakest forces (weak and gravitational)

What particles carry out electromagnetic interaction? (photon)

Voiced by group leaders of answers to questions and exchange of cards.

Lesson summary.

You have become acquainted with some aspects of the development of modern physics and now have elementary representations about the direction in which our science is developing and why we need it.

6. Homework. Paragraph 28.

First group tasks:

1. How many fundamental particles are there in total? ______________

2. Quark composition of the electron? ____________

3. List the two strongest interactions ______

4. Total number of gluons? _______

___________________________________________________________________

Second group tasks:

1. How many particles underlie the universe? ________

2. Quark composition of the proton? ___________

___________________________________________________________________

First group tasks:

1. How many fundamental particles are there in total? __________

2. Quark composition of the electron? __________

3. List the two strongest interactions _______________________________________________________________________________

4. Total number of gluons? _________

___________________________________________________________________

Second group tasks:

1. How many particles underlie the universe? ____________

2. Quark composition of the proton? _____________

3. List the two weakest interactions ______________________

4. What particles carry out electromagnetic interaction? ______

___________________________________________________________________

First group tasks:

1. How many fundamental particles are there in total? _____________

2. Quark composition of the electron? ______________

3. List the two strongest interactions ___________________________________________________________________________

4. Total number of gluons? _____

___________________________________________________________________

Second group tasks:

1. How many particles underlie the universe? ______

2. Quark composition of the proton? _________

3. List the two weakest interactions _______________________

4. What particles carry out electromagnetic interaction? _______

Municipal budget educational institution –

average comprehensive school No. 7 Belgorod

Public lesson in physics

Grade 11

"Elementary particles"

Prepared and conducted:

Physics teacher

Polshchikova A.N.

Belgorod 2015

Topic: Elementary particles.

Lesson type: lesson of studying and primary consolidation of new knowledge

Teaching method: lecture

Form of student activity: frontal, collective, individual

The purpose of the lesson: expand students’ understanding of the structure of matter; consider the main stages in the development of elementary particle physics; give the concept of elementary particles and their properties.

Lesson objectives:

Educational : to introduce students to the concept of an elementary particle, the typology of elementary particles, as well as methods for studying the properties of elementary particles;

Developmental: to develop the cognitive interest of students, ensuring their feasible involvement in active cognitive activity;

Educational: education of universal human qualities - awareness of perception scientific achievements in the world; developing curiosity and endurance.

Equipment for the lesson:

Didactic materials: textbook material, cards with tests and tables

Visual aids: presentation

During the classes

(Presentation)

1. Organization of the beginning of the lesson.

Teacher's activities: Mutual greetings between the teacher and students, fixing students, checking students’ readiness for the lesson. Organization of attention and inclusion of students in the business rhythm of work.

Predicted student activity: organizing attention and inclusion in the business rhythm of work.

2. Preparation for the main stage of the lesson.

Teacher's activities: Today we will start studying a new section " Quantum physics" - “Elementary particles.” In this chapter we will talk about the primary, further indecomposable particles from which all matter is built, about elementary particles.

Physicists discovered the existence of elementary particles when studying nuclear processes, so until the middle of the 20th century, elementary particle physics was a branch of nuclear physics. Currently, particle physics and nuclear physics are close but independent branches of physics, united by the commonality of many problems considered and the research methods used.

The main task of elementary particle physics is the study of the nature, properties and mutual transformations of elementary particles.

It will also be our main task in studying the physics of elementary particles.

3. Assimilation of new knowledge and methods of action.

Teacher's activities: Lesson topic: "Stages of development of elementary particle physics." In this lesson we will look at the following questions:

The history of the development of ideas that the world consists of elementary particles

What are elementary particles?

How can one obtain an isolated elementary particle and is it possible?

Typology of particles.

The idea that the world is made of fundamental particles has a long history. Today, there are three stages in the development of elementary particle physics.

Let's open the textbook. Let's get acquainted with the names of the stages and time frames.

Stage 1. From electron to positron: 1897 - 1932.

Stage 2. From positron to quarks: 1932 - 1964.

Stage 3. From the quark hypothesis (1964) to the present day.

Teacher's activities:

Stage 1.

Elementary, i.e. the simplest, further indivisible, this is how the famous ancient Greek scientist Democritus imagined the atom. Let me remind you that the word “atom” in translation means “indivisible”. For the first time, the idea of the existence of tiny, invisible particles that make up all surrounding objects was expressed by Democritus 400 years BC. Science began to use the concept of atoms only in early XIX century, when on this basis it was possible to explain a number of chemical phenomena. And at the end of this century the complex structure of the atom was discovered. In 1911, the atomic nucleus was discovered (E. Rutherford) and it was finally proven that atoms have a complex structure.

Let's remember guys: what particles are part of the atom and briefly characterize them?

Predicted student activity:

Teacher's activities: guys, maybe some of you remember: by whom and in what years were the electron, proton and neutron discovered?

Predicted student activity:

Electron. In 1898, J. Thomson proved the reality of the existence of electrons. In 1909, R. Millikan first measured the charge of an electron.

Proton. In 1919, E. Rutherford, while bombarding nitrogen with particles, discovered a particle whose charge was equal to the charge of an electron, and whose mass was 1836 times greater than the mass of the electron. The particle was named proton.

Neutron. Rutherford also suggested the existence of a chargeless particle whose mass is equal to the mass of a proton.

In 1932, D. Chadwick discovered the particle that Rutherford had suggested and called it the neutron.

Teacher's activities: After the discovery of the proton and neutron, it became clear that the nuclei of atoms, like the atoms themselves, have a complex structure. The proton-neutron theory of the structure of nuclei arose (D. D. Ivanenko and V. Heisenberg).

In the 30s of the 19th century, in the theory of electrolysis developed by M. Faraday, the concept of -ion appeared and the elementary charge was measured. The end of the 19th century - in addition to the discovery of the electron, was marked by the discovery of the phenomenon of radioactivity (A. Becquerel, 1896). In 1905, the concept of quanta arose in physics. electromagnetic field- photons (A. Einstein).

Let's remember: what is a photon?

Predicted student activity: Photon (or quantum of electromagnetic radiation) is an elementary light particle, electrically neutral, devoid of rest mass, but possessing energy and momentum.

Teacher's activities: open particles were considered indivisible and unchangeable primary essences, the basic building blocks of the universe. However, this opinion did not last long.

Stage 2.

In the 1930s, the mutual transformations of protons and neutrons were discovered and studied, and it became clear that these particles are also not the unchanging elementary “building blocks” of nature.

Currently, about 400 subnuclear particles are known (the particles that make up atoms, which are usually called elementary). The vast majority of these particles are unstable (elementary particles transform into each other).

The only exceptions are the photon, electron, proton and neutrino.

The photon, electron, proton and neutrino are stable particles (particles that can exist in a free state indefinitely), but each of them, when interacting with other particles, can turn into other particles.

All other particles undergo spontaneous transformations into other particles at certain intervals, and this main fact their existence.

I mentioned one more particle - the neutrino. What are the main characteristics of this particle? By whom and when was it discovered?

Predicted activity of the student: Neutrino is a particle devoid of electric charge and its rest mass is 0. The existence of this particle was predicted in 1931 by W. Pauli, and in 1955, the particle was experimentally registered. Manifests itself as a result of neutron decay:

Teacher's activities: Unstable elementary particles differ greatly in their lifetimes.

The longest-lived particle is the neutron. The neutron lifetime is about 15 minutes.

Other particles “live” for a much shorter time.

There are several dozen particles with a lifetime exceeding 10 -17 With. On the scale of the microcosm, this is a significant time. Such particles are calledrelatively stable .

Majority short-lived elementary particles have lifetimes of the order of 10-22 -10 -23 s.

The ability for mutual transformations is the most important property of all elementary particles.

Elementary particles are capable of being born and destroyed (emitted and absorbed). This also applies to stable particles, with the only difference being that transformations of stable particles do not occur spontaneously, but through interaction with other particles.

An example would beannihilation (i.e. disappearance ) electron and positron, accompanied by the birth of high-energy photons.

A positron is (an antiparticle of an electron) a positively charged particle that has the same mass and the same (in absolute value) charge as an electron. We'll talk about its characteristics in more detail in the next lesson. Let's just say that the existence of the positron was predicted by P. Dirac in 1928, and discovered in 1932 in cosmic rays K. Anderson.

In 1937, particles with a mass of 207 electron masses were discovered in cosmic rays, calledmuons ( -mesons ). Average life time-meson is equal to 2.2 * 10-6 s.

Then in 1947-1950 they openedpeonies (i.e. -mesons). Average lifetime of neutral-meson - 0.87·10 -16 s.

In subsequent years, the number of newly discovered particles began to grow rapidly. This was facilitated by research into cosmic rays, the development of accelerator technology and the study of nuclear reactions.

Modern accelerators are necessary to carry out the process of creating new particles and studying the properties of elementary particles. The initial particles are accelerated in the accelerator to high energies “on a collision course” and collide with each other in a certain place. If the energy of the particles is high, then during the collision process many new particles, usually unstable, are born. These particles, scattering from the point of collision, disintegrate into more stable particles, which are recorded by detectors. For each such act of collision (physicists say: for each event) - and they are recorded in thousands per second! - experimenters as a result determine kinematic variables: the values of the impulses and energies of the “caught” particles, as well as their trajectories (see figure in the textbook). By collecting many events of the same type and studying the distributions of these kinematic quantities, physicists reconstruct how the interaction occurred and what type of particles the resulting particles can be attributed to.

Stage 3.

Elementary particles are combined into three groups: photons , leptons And hadrons (Appendix 2).

Guys, list me the particles belonging to the group of photons.

Predicted student activity: To the group photons refers to a single particle - a photon

Teacher's activities: the next group consists of light particlesleptons .

: this group includes two types of neutrinos (electron and muon), electron and?-meson

Teacher's activities: Leptons also include a number of particles not listed in the table.

The third large group consists of heavy particles called hadrons. This group is divided into two subgroups. Lighter particles form a subgroup mesons .

Predicted student activity: the lightest of them are positively and negatively charged, as well as neutral -mesons. Pions are quanta of the nuclear field.

Teacher's activities: second subgroup -baryons - includes heavier particles. It is the most extensive.

Predicted student activity: The lightest baryons are nucleons - protons and neutrons.

Teacher's activities: they are followed by the so-called hyperons. Omega-minus-hyperon, discovered in 1964, closes the table.

The abundance of discovered and newly discovered hadrons led scientists to believe that they were all built from some other more fundamental particles.

In 1964, the American physicist M. Gell-Man put forward a hypothesis, confirmed by subsequent research, that all heavy fundamental particles - hadrons - are built from more fundamental particles calledquarks.

From a structural point of view, the elementary particles that make up atomic nuclei(nucleons), and in general all heavy particles - hadrons (baryons and mesons) - consist of even simpler particles, which are usually called fundamental. This role of truly fundamental primary elements of matter is played by quarks, the electric charge of which is equal to +2/3 or -1/3 of the unit positive charge of a proton.

The most common and light quarks are called up and down and are designated, respectively, u (from English up) and d (down). Sometimes they are also called proton and neutron quarks due to the fact that the proton consists of a combination of uud, and the neutron - udd. The top quark has a charge of +2/3; bottom - negative charge -1/3. Since a proton consists of two up quarks and one down quark, and a neutron consists of one up and two down quarks, you can independently verify that the total charge of a proton and neutron is strictly equal to 1 and 0.

The other two pairs of quarks are part of more exotic particles. Quarks from the second pair are called charmed - c (from charmed) and strange - s (from strange).

The third pair consists of true - t (from truth, or in the English tradition top) and beautiful - b (from beauty, or in the English tradition bottom) quarks.

Almost all particles consisting of various combinations of quarks have already been discovered experimentally.

With the acceptance of the quark hypothesis, it was possible to create a harmonious system of elementary particles. Numerous searches for quarks in the free state, carried out at high-energy accelerators and in cosmic rays, have been unsuccessful. Scientists believe that one of the reasons for the unobservability of free quarks is perhaps their very large masses. This prevents the birth of quarks at the energies that are achieved in modern accelerators.

However, in December 2006, a strange message about the discovery of “free top quarks” was broadcast across scientific news agencies and the media.

4. Initial check of understanding.

Teacher's activities: so guys, we've covered:

main stages in the development of particle physics

found out which particle is called elementary

got acquainted with the typology of particles.

In the next lesson we will look at:

more detailed classification elementary particles

types of interactions of elementary particles

antiparticles.

And now I suggest you take a test to revive in your memory the main points of the material we have studied (Appendix 3).

5. Summing up the lesson.

Teacher's activities: Giving grades to the most active students.

6. Homework

Teacher's activities:

1. § 114 - 115

2. abstract.