Lesson developments (lesson notes)
Line UMK A.V. Peryshkin. Physics (7-9)
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Lesson topic: Thermal motion. Temperature. Internal energy.
A traditional lesson on discovering new knowledge, acquiring new skills and abilities with elements of problem-based learning in the 8th grade of a comprehensive school, studying according to the program of A.V. Peryshkin (45 minutes).
Activity goal:
- Teach children new ways of finding knowledge, introduce new concepts (thermal motion, temperature, internal energy), repeat previously studied material (diffusion, basics of MCT, mechanical energy).
- To acquaint students with the main characteristics of thermal processes, teach them to explain the reasons for the existence and changes in the internal energy of the body;
- Expand students' knowledge by including new names (Democritus, M. Arnold), terms (energy transformation) and comparative descriptions (temperature scale, internal energy, the universal nature of the law of conservation of energy).
Planned educational results
Subject:
- Explain the thermal motion of particles; introduce the concept of temperature; establish a connection between the temperature of a body and the speed of movement of its molecules, introduce students to the basic characteristics of thermal processes, with thermal motion as a special type of motion.
- Demonstrate a visual series of instruments that measure temperature and experiments that indirectly demonstrate the existence of internal energy.
- Give examples of thermal phenomena and comparative descriptions.
Metasubject:
Regulatory:
- Together with schoolchildren, set new achievement goals, transform practical tasks into intellectual and cognitive activities;
- Teach children to independently analyze the conditions for achieving a goal based on the guidelines identified by the teacher; adequately assess the correctness of actions and make the necessary adjustments.
Cognitive:
- Form general educational activities by introducing physical concepts; generalization of cognitive material; explanations of natural phenomena and processes that occur in the surrounding world; analysis of the received information presented in different sign systems (text, diagram, audiovisual series).
- Establish cause-and-effect relationships; learn to build logical reasoning.
Communicative: Ask questions that develop attention and memory (through completing a problem task and working with the conceptual apparatus); thinking (through solving qualitative problems); speech and learning to formulate thoughts (through inclusion in the discussion process).
Personal: Promote acceptance of the norms and requirements of school life, the rights and responsibilities of the student.
The graduate will have the opportunity for the development of pronounced sustainable educational and cognitive motivation through the formation of ideas about the unity and interconnection of natural phenomena, readiness for self-education.
Lesson equipment: presentation “Thermal motion. Temperature. Internal energy”, basic summary, test with tasks, vessels with hot, warm and cold water.
Epigraph(On the desk):
"Nothing exists but atoms."
Democritus
Lesson stage (goal setting, time) |
Forms of educational activities / Contents of the lesson stage |
Tasks for students, the completion of which will lead to the achievement of planned results |
Planned results |
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Subject |
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Stage of motivation (self-determination) for educational activities. Goal: Creating conditions for identifying the mood of children and their readiness for fruitful activities. (2 minutes) |
Introductory words from the teacher: Guys! You know that the world of physics is interesting and diverse. Living in an environment of scientific and technological progress, we have the opportunity to explore the natural world and compare our observations with scientific facts. The more unexpected our discoveries, the more interesting science is to us. Let's see?! |
Epigraph for the lesson Intellectual warm-up. The visuals show examples of thermal phenomena.
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Democritus, thermal phenomena |
Personal: accept the rules of behavior in the classroom |
Updating and recording individual difficulties in a trial action . Goal: Activate thought processes to assimilate new knowledge (5 minutes) |
Thermal phenomena occur around us all the time. They are characterized by a change in temperature or physical state of bodies. You are well aware that for the objectivity of temperature measurement there is a device - a thermometer. Conclusion: There are instruments with different scales for measuring temperature. Currently, most countries use the International Practical Temperature Scale (Celsius scale) for scientific and practical purposes. |
Health-saving aspect (speaking hotly is dangerous...) Problematic question.
Experiment confirming the conclusions: Three vessels with water - hot, warm, cold. The student puts one hand into a vessel with hot water and the other into a vessel with cold water. After some time, lower both hands into a vessel with warm water. Describe your feelings. Visual analysis The visual series shows a series of instruments for measuring temperature with different scales (0R, 0F, . 0K, 0C)
Health-saving aspect (speak - mercury is dangerous!) |
Temperature temp. scale, thermometer |
Personal: promote orientation in the world (meaning formation) Regulatory: Setting new goals and transforming them into practical tasks (goal setting, forecasting) |
The stage of identifying the location and cause of difficulties Goal: To review the material covered and create conditions for students to understand the causes of difficulties when solving a trial task. (4 min) |
Conclusion: Diffusion (the mutual penetration of molecules of one substance into another) occurs faster at higher temperatures. Conclusion: Molecules of the same substance are identical. The difference is in the speed of movement of the molecules. Conclusion: Molecules move along a complex trajectory. When moving, they experience numerous collisions with each other, which lead to a change in the direction of their movement. Continue the phrase: “The speed of movement of the molecules of the body depends on ..... The random movement of a huge number of molecules in the body is called - .....” |
Trick questions:
Why do odors spread so much more slowly? Speculating on the definition of “thermal motion”. Working with reference notes (For the supporting summary form, see Appendix No. 2) |
The concept of thermal motion of molecules, the main characteristics of thermal processes, thermal motion as a special type of motion |
Cognitive: independently highlight and formulate the cognitive purpose of the lesson Communicative skills: formulate your own opinion, the ability to construct speech statements. |
The stage of constructing a project to get out of the current situation Purpose: Formulate the purpose and topic of the lesson (6 min) |
Students are asked to solve the tasks of Part 1 of the OGE in Physics. For selected tasks, see Appendix No. 1 Let's check the correctness of your answers. If everything is decided correctly, then you will receive a hint word.
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Independent completion of the test task |
Control and correction of skills |
Cognitive: be able to solve test tasks, establish cause-and-effect relationships. Regulatory: goal setting, including setting new goals, transforming a practical task, |
Stage of primary consolidation with pronunciation in external speech Goal: Create an educational environment for including students in activities to achieve lesson goals (7 min) |
Matthew Arnold said, “Genius depends chiefly on energy.” While studying mechanical phenomena, we learned that kinetic and potential energy can be converted into each other in such a way that their sum remains constant. This is one of the most general and fundamental laws of nature - the law of conservation and transformation of energy. Energy does not disappear without a trace, it only passes from one form to another. |
Repetition of the material covered in 7th grade. Answers on questions:
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Energy (mechanical-potential and kinetic), unit of energy, letter designation of energy, law of conservation and transformation of energy, M. Arnold |
Communicative: listening and understanding the speech of others Regulatory: assessing and taking into account the nature of mistakes made when analyzing issues |
Stage of independent work with verification against the standard Goal: Create a situation of success for each student, promote the development of natural science literacy. |
In real experiments, the patterns of energy conversion look much more complicated. Before answering this question, let's do some practical work. Everyone’s task is to consciously analyze the issues and write down the information briefly. |
Problematic question
Practical work with elements of experimental activity (work in pairs) |
The concept of internal energy, designation and unit of measurement of internal energy, thermal motion of molecules, interaction of molecules, relative position of molecules |
Personal: self-knowledge through analysis of additional information. Regulatory: setting new goals, transforming practical tasks into cognitive activity; adequacy self-assessment of the correctness of performing actions and making the necessary adjustments. Communicative: the ability to ask questions necessary to organize one’s own activities, to formulate one’s own opinion. Cognitive: explain phenomena, processes, connections and relationships identified during practical work. |
Conclusion: If we look at our hand through a microscope with high magnification, we will see that the smallest particles of the skin are constantly moving and interacting with each other. Upon impact, the palms were deformed (this can only be seen under high magnification), and we felt warm. When the body heats up, the average speed of movement of the molecules in the hand increases. This means that their average kinetic energy has increased. Molecules also have potential energy. After all, they interact with each other - they attract and repel. When the body was deformed, the relative position of the molecules changed, and therefore the potential energy. This means that the mechanical energy of the body has turned into the energy of the molecules of this body. |
Working with reference note No. 1. I invite you to clap your hands and describe, using physical concepts, the transition of energy.
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Bodies have internal energy. Internal energy is a new concept for you. |
Working with textbook text
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Let me give you a few examples for comparison: The total kinetic energy of thermal motion of molecules in a three-liter jar of water at room temperature is numerically equal to the work that needs to be done to lift a car to the 25th floor. In order for a three-liter kettle to boil completely, it is necessary to impart energy to the water that would be enough to lift a loaded dump truck to the same 25th floor. Even greater changes in internal energy can occur during chemical reactions, when some substances are converted into others. For example, the combustion of 3 liters of gasoline releases energy that would be enough to lift two loaded freight cars to the 25th floor.… Internal energy is a physical quantity. Denoted by –U. Unit of measurement - J |
Working with the supporting notes, try to formulate your own point of view and arguments for it on the proposed issues:
Express your thoughts: which of two bodies of the same mass, consisting of the same substance, but located in different states of aggregation, has a large internal energy, all other things being equal? |
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Stage of inclusion in the knowledge system and repetition Goal: To record the acquired knowledge, to consider how the new knowledge fits into the system of what was previously learned, and, if possible, to bring the acquired skill to automated use |
Discussion of the answers that the guys, when working in pairs, wrote down on the supporting note form. Internal energy depends on temperature, state of aggregation and body mass. |
Working with a supporting outline. The game is believe it or not. Do you believe that the internal energy of the body depends on....
Give examples : Make a guess whether a body can simultaneously possess both internal and mechanical energy. |
Dependence of internal energy |
Regulatory: learn to adequately self-assess acquired knowledge |
An intermediate stage at which homework is formulated. |
Solving quality problems:
Homework:§1-2 + additional 3 task to choose from (see Appendix No. 3) |
Primary control and correction of skills |
Personal: accept the rules for performing tasks |
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Reflection stage of educational activities in the lesson |
Complete the sentences
Thank you for the lesson. |
Regulatory: learn to adequately conduct self-assessment Communicative: the ability to express one’s thoughts. |
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Brief self-analysis of the lesson: The structure matches the objectives and type of lesson. The material was selected in a variety of forms, means, methods of work, and was also differentiated in complexity and volume. Presented in accessible language with many examples from practical life. When consolidating the studied material, various types of OGE format tasks are used. The lesson will be effective if you work at a productive pace and cooperate kindly with each student.
Lesson #2
Thermal movement.
Internal energy.
Ways to change internal energy.
Physical phenomena associated with temperature changes are called thermal.
Examples of thermal phenomena:
- heating and cooling
- melting and crystallization
- vaporization (boiling and evaporation) and condensation
- combustion
- thermal expansion
Temperature - – This is a physical quantity that characterizes different degrees of heating of a body.
Temperature is measured using a thermometer and expressed in degrees Celsius.
- The patterns of many physical phenomena depend on temperature.
- It is known, for example, that diffusion occurs faster at higher temperatures and slower at low temperatures.
- Therefore, the speed of movement of molecules and temperature are related.
- Body temperature depends on the speed of movement of molecules .
- As the temperature increases, the speed of molecular movement increases, and as the temperature decreases, it decreases. .
- All molecules of any substance move continuously and randomly (chaotically).
- The movement of molecules in different bodies occurs differently. Gas molecules move randomly at high speeds (hundreds of m/s) throughout the entire volume of gas. When they collide, they bounce off each other, changing the magnitude and direction of the velocities. Liquid molecules oscillate around equilibrium positions (since they are located almost close to each other) and relatively rarely jump from one equilibrium position to another. The movement of molecules in liquids is less free than in gases, but more free than in solids. In solids, particles vibrate around an equilibrium position. With increasing temperature, the speed of particles increases, therefore the chaotic movement of particles is usually called thermal.
- The concept of temperature does not apply to an individual molecule. We can only talk about temperature if there is a sufficiently large population of particles.
- The number of atoms and molecules in the bodies around us is large. For example, 1 cm of water contains ~ 3 * 10 molecules.
- Each of the molecules participates in thermal motion, therefore with a change in thermal motion, the state of the body and its properties also change.
- Body temperature is closely related to the average kinetic energy of molecules.
- The higher the temperature of a body, the greater the average kinetic energy of its molecules . As the temperature of a body decreases, the average kinetic energy of its molecules decreases.
- It is known that there are 2 types of mechanical energy: kinetic energy and potential energy.
- Kinetic energy is the energy possessed by all moving bodies. Kinetic energy depends on the mass and speed of the body.
- Potential energy - this is the energy that bodies possess due to interaction with other bodies. Potential energy is determined by the relative position of the interacting bodies of the aphid and its individual parts.
- Kinetic and potential energy is two types of mechanical energy, they can turn into each other.
kinetic energy increases. Lift height decreases = potential energy decreases. Potential energy is converted into kinetic energy. When the ball hits the plate and stops: Mechanical energy is converted into another form of energy. Kinetic and potential energy relative to the plate are zero." width="640" Let's raise and lower a lead ball lying on a lead plate.
- When falling :
- The speed of the ball increases = kinetic energy increases.
- Lift height decreases = potential energy decreases.
Potential energy is converted into kinetic energy.
- When the ball hits the plate and stops:
Mechanical energy is converted into
another form of energy.
Kinetic and potential energy
relative to the plate are equal to zero.
the relative position of the lead molecules has changed = the potential energy of the lead molecules has changed. The ball and the plate have heated up after the impact = the speed of the lead molecules has changed = the kinetic energy of the lead molecules has changed." width="640" - The ball and plate were deformed after the impact = the relative arrangement of lead molecules has changed = changed potential energy lead molecules
- The ball and plate became hot after the impact = the speed of lead molecules has changed = kinetic has changed energy lead molecules.
Therefore, mechanical energy
which the ball possessed at the beginning of the experiment passed
into molecular energy.
- All bodies are made up of molecules that continuously move and interact with each other.
- They have both kinetic and potential energy.
- These energies constitute the internal energy of the body.
- Internal energy - this is the energy of movement and interaction of particles that make up the body.
- Internal energy characterizes the thermal state of the body.
- Internal energy depends on the temperature and state of aggregation of the substance (mutual arrangement of molecules).
- Internal energy does not depend neither from the mechanical movement of the body, nor from the position of the body relative to other bodies.
- Internal energy cannot be equal to zero and big enough since the body contains a huge number of molecules.
- If you take an ordinary match, then it contains such a value of internal energy that it is enough to split the globe in half.
- Or, for example, with a decrease in the temperature of the globe by just one degree, energy would be released that would be approximately a billion times greater than that produced annually by all the power plants in the world.
The internal energy of the body can be changed.
Give about 50 intense hammer blows to
iron object. Feel the change
metal and hammer temperatures. Explain the phenomenon.
Place a coin on a piece of wooden board
and rub it vigorously, pressing it to the surface,
within a few minutes. Check with your hands
how the temperature of the coin changed.
Explain the result.
Take a rubber band tied with a ring,
Apply the tape to your forehead and note its temperature.
Holding the rubber with your fingers, several
stretch vigorously once and in a stretched form
press it to your forehead again. Draw a conclusion about the temperature
and the reasons that caused the change.
Conclusion: When doing work on the body
its internal energy increases.
- If a piece of aluminum wire is riveted on an anvil or quickly bent in the same place, first in one direction or the other, then this place becomes very hot. Explain the phenomenon.
- Measure the water temperature with a home thermometer,
poured into a jar or bottle. Close the container tightly
and shake it vigorously for 10–15 minutes,
then measure the temperature again.
To prevent heat transfer from hands,
put on mittens or wrap the vessel in a towel.
Which way of changing internal energy do you
used? Explain.
- The hammer also heats up when it is struck on the anvil.
Conclusion: When work is done on a body, its internal energy increases.
- Take a new, whole plastic bag. Rinse the inside of the bag with hot water until any drops remain. Tie it tightly to the end of a bicycle pump or a large rubber bulb. Pump air vigorously into the bag until it bursts. There will be fog in the air. Explain the observed phenomenon.
Conclusion: If work is done above the body , his internal energy increases . If the work is done the body itself , his internal energy decreases.
"AIR FIRE"
- If you put a piece of cotton wool into a cylinder with a piston and sharply lower (push in) the piston, the cotton wool will ignite! Work is done on the air inside the piston - its volume decreases.
This leads to an increase in the internal energy of the air and its temperature increases, which leads to the ignition of the cotton wool.
- The internal energy of bodies can be changed by heat transfer.
- The process of changing internal energy without doing work on the body is called heat transfer.
- What thermal phenomena do you know?
- What does temperature characterize?
- How is temperature related to the speed of movement of its molecules?
- How does the movement of molecules differ in gases, liquids and solids?
- What energy is called the internal energy of a body?
- What does the internal energy of a body depend on?
- What does the internal energy of a body not depend on?
- Name ways to change internal energy.
- && 1-3;
- questions on page 7
- questions 5-6 page 10
- Additionally: questions 1-4 p.10
- task 1 p.10, questions 1,2 p.7
“Thermal phenomena grade 8” - Does a microwave oven emit harmful radiation? Does water in a black kettle cool faster than in a white one? To answer the above questions, I suggest working on projects. 2. It’s not clear why...? The moon shines, but does not warm? Have you ever thought about the question: Why is it comfortable to live in a modern house? Thermal phenomena in your home.
“Thermal motion” - The trajectory of three Brownian particles. Atoms and molecules. Thermal engine. Solids retain both volume and shape. Isotopes of hydrogen. Thermometers. Initial information about the structure of matter. Thermal motion of molecules in a liquid. Molecules of a liquid vibrate around an equilibrium position.
“Temperature and thermal equilibrium” - Kelvin scale. Temperature properties: Temperature. Fahrenheit. Celsius. A measure of the average kinetic energy of molecules. Topic: "Temperature". The purpose of the lesson:
“Thermal pollution” - Vibration or dynamic impact - a set of mechanical vibrations. Transmitted from sources to various objects, including living nature. Sources: equipment of industrial enterprises, moving vehicles, construction machines and mechanisms, technical equipment of buildings, etc.
“Thermal radiation” - The proportionality coefficient is called the thermal conductivity coefficient. Convection. Leads to equalization of body temperature. Examples of convection. Thermal radiation. Examples of thermal conduction: Examples of radiation. Thermal conductivity in nature and technology.
"Thermal movement temperature" - Source of information about temperature. Any thermometer shows its own temperature. In liquids and gases, molecules move randomly, colliding with each other. Temperature". What explains the increase in the rate of diffusion with increasing temperature? Warm water consists of the same molecules as cold water.
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You need to heat a full kettle of water 1. to 50 0 C 2. to C Which kettle will require less heat?
