Lecture the law of conservation of energy in thermal processes. wooden splinter, thermometer, scales with weights. History of the study of the transformation of mechanical and thermal energy
A little earlier, we have already considered some phenomena of energy conversion in mechanical processes. Let's refresh our knowledge. Throwing an object (a stone or a ball) into the sky, we give it the energy of motion, or in other words kinetic energy. Having risen to a certain level of height, the movement of the object slows down, after which a fall occurs. At the moment of stopping (when the movement of the object has stopped at the top point), all kinetic energy is converted into potential energy.
During such transformations, the sum of kinetic and potential energy remains unchanged. If we assume that the potential energy near the surface of the Earth is equal to zero, the sum of the kinetic energy, together with the potential energy of the body at absolutely any height during the rise or fall, will be equal to: E = E k + E n
We conclude: the total amount of potential and kinetic energy of the body remains unchanged if only elastic and gravitational forces act, and there is no friction force. That's what it is the law of conservation of mechanical energy.
When we experimented with dropping a lead ball on a slab, we observed how mechanical energy turned into internal energy. Thus, such types of energy as mechanical and internal can pass from one body to another.
A similar conclusion applies to all thermal processes. During heat transfer, for example, a body that is heated more strongly gives off energy, at the same time when a less heated body only receives it.
During the process of processing by the engine of the fuel machine, internal energy fuel is converted into mechanical energy of motion. When energy passes from one body to another, or when one form of energy is transformed into another, energy is always conserved.
The study of phenomena that relate to the transformation of one type of energy into a completely different one has led to the discovery of one of the main laws of nature - the law of conservation and transformation of energy.
In any natural phenomenon, energy cannot arise or disappear just like that. It simply passes from one form to another, while its value is always preserved.
When scientists examined various natural phenomena, they have always relied on this law. Now, we can make an important conclusion: energy cannot arise from a body if it has not received it from some other body. Here are some examples to better understand the material.
The rays of the sun contain a certain amount of energy. Touching the surface of the Earth, they give off heat to it, heat it up. Thus, solar energy is converted into the internal energy of the soil and bodies that are on the surface of the earth. The air, which is heated from the surface of the earth, begins to move - this is how the wind is born. The transformation of internal energy, which is endowed with air masses, into mechanical energy begins.
Some of the solar energy is absorbed by the leaves of plants. Complex chemical reactions (photosynthesis) begin to occur, as a result of which organic compounds are formed, i.e. solar energy is converted into chemical energy. 
The transition of intra-atomic energy into different types of energy is often used in practice. The law of conservation of energy is the scientific basis for various kinds of calculations in absolutely all areas of science and technology. It must be understood that internal energy cannot be completely converted into mechanical energy.
History has a huge number of projects " perpetual motion machine". In some cases the errors of the "inventor" were obvious, in others these errors were hidden behind the complex design of the device. Unsuccessful attempts to create a "perpetual motion machine" continue today. All of them are doomed to failure, because the law of conservation and transformation of energy denies the receipt of work without the expenditure of energy.
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1. For mechanical phenomena, under certain conditions, the law of conservation of mechanical energy is fulfilled: the total mechanical energy of a system of bodies is conserved if they interact with the forces of gravity or elasticity. If friction forces act, then the total mechanical energy of the bodies is not conserved, part of it (or all) is converted into their internal energy.
When the state of the body (system) changes, its internal energy changes. The state of the body and, accordingly, its internal energy can be changed in two ways: in the process of heat transfer or by performing work on the body by external forces (work, for example, friction forces).
2. When solving the problem in the previous paragraph, it was obtained that the amount of heat \(Q_1 \) given hot water, is equal to the amount of heat \(Q_2 \) obtained cold water, i.e.: \(Q_1=Q_2 \) .
The written equality is called equation heat balance . It relates the amount of heat received by one body and the amount of heat given off by another body during heat exchange. In this case, not two bodies, but three or more can participate in heat exchange. For example, if a spoon is lowered into a glass of hot tea, then the glass and tea will participate in the heat exchange (give energy), and the spoon and the surrounding air (receive energy). As already mentioned, in specific problems we can neglect the amount of heat received or given off by some bodies during heat exchange.
3. The heat balance equation makes it possible to determine certain quantities. In particular, the values of the specific heat capacity of substances are determined from the heat balance equation.
A task. Determine the specific heat capacity of aluminum if, when lowering an aluminum spoon weighing 42 g at a temperature of 20 °C into a glass containing 92 g of water at 75 ° C, a temperature of 70 ° C is established in the glass. The energy losses for heating the air, as well as the energy given off by the glass, should be neglected.
Task Analysis. Two bodies are involved in heat exchange: hot water and an aluminum spoon. Water gives off the amount of heat \ (Q_1 \) and cools down from 75 to 70 ° С. An aluminum spoon receives the amount of heat \ (Q_2 \) and heats up from 20 to 70 ° C. The amount of heat \(Q_1 \) given by hot water is equal to the amount of heat \(Q_2 \) received by the spoon.
Problem solving in general view: heat balance equation: \(Q_1=Q_2 \) ; the amount of heat given off by hot water: \(Q_1=c_1m_1(t_1-t) \) ; the amount of heat received by an aluminum spoon: \(Q_2=c_2m_2(t-t_2) \) . With this in mind, the heat balance equation: \(c_1m_1(t_1-t)=c_2m_2(t-t_2) \). From: \(c_2=c_1m_1(t_1-t)/m_2(t-t_2) \).
4. The law of conservation of energy in thermal processes is fulfilled when bodies are heated due to the energy released during the combustion of fuel. Fuel is natural gas, wood, coal, oil. When it burns, a chemical oxidation reaction occurs - carbon atoms combine with oxygen atoms contained in the air, and a molecule of carbon monoxide (carbon dioxide) CO 2 is formed. This releases energy.
When different fuels of the same mass are burned, different amount warmth. For example, it is well known that natural gas is an energy-efficient fuel than firewood. This means that in order to obtain the same amount of heat, the mass of firewood to be burned must be significantly greater than the mass of natural gas. Consequently, various types of fuel from an energy point of view are characterized by a quantity called specific heat of combustion of fuel.
The specific heat of combustion of a fuel is a physical quantity showing how much heat is released during the complete combustion of a fuel weighing 1 kg.
The specific heat of combustion of fuel is denoted by the letter \ (q \) , its unit is 1 J / kg.
The value of the specific heat of combustion of the fuel is determined experimentally. Hydrogen has the highest specific heat of combustion, and gunpowder has the lowest.
The specific heat of combustion, for example, of oil is 4.4·10 7 J/kg. This means that with the complete combustion of 1 kg of oil, the amount of heat 4.4 10 7 J is released.
AT general case, if the mass of the fuel is \(m \) , then the amount of heat \(Q \) released during its complete combustion is equal to the product of the specific heat of combustion of the fuel \(q \) by its mass \(m \) :
5. Suppose that the internal energy of the body \(U \) was changed by doing work on it \(A \) and imparting to it a certain amount of heat \(Q \) . In this case, the change in internal energy \(U \) is equal to the sum of the work \(A \) performed on the body and the amount of heat transferred to it \(Q \) :
The written expression is first law of thermodynamics 1 , which is a generalization of the energy conservation law. It is formulated as follows: the change in the internal energy of the system during the transition from one state to another is equal to the sum of the work done on the system by external forces and the amount of heat transferred to the system.
1 Thermodynamics - the study of thermal processes.
Suppose that the work is done not by external forces, but by the body itself. His work in this case is \(A^(‘)=-A \) and \(Q=U+A^(‘) \) . The amount of heat transferred to the body is used to change its internal energy and to work the body against external forces.
6. Devices that perform mechanical work due to the internal energy of the fuel are called heat engines.
Any heat engine consists of a heater, a refrigerator and a working fluid (Fig. 72). Gas or steam is used as a working fluid, since they are highly compressible, and depending on the type of engine, there can be fuel (gasoline, kerosene), water vapor, etc. The heater transfers a certain amount of heat to the working fluid \ ((Q_1) \) , and its internal energy increases, mechanical work \((A) \) is performed due to this internal energy, then the working fluid gives off a certain amount of heat to the refrigerator \((Q_2) \) and cools down to the initial temperature. The described scheme represents the engine operation cycle and is general; in real engines, various devices can play the role of a heater and a refrigerator. The environment can serve as a refrigerator.
Since in the engine part of the energy of the working fluid is transferred to the refrigerator, it is clear that not all of the energy received by it from the heater goes to doing work. Accordingly, the coefficient useful action engine (efficiency) is equal to the ratio of the perfect work \ ((A) \) to the amount of heat received by it from the heater \ ((Q_1) \) :
\[ Efficiency=\frac(A)(Q_1)100\%=\frac(Q_1-Q_2)(Q_1)100\% \]
The efficiency factor is usually expressed as a percentage.
7.
There are two types of internal combustion engines (ICE): carburetor and diesel. In a carburetor engine, the working mixture (a mixture of fuel with air) is prepared outside the engine in a special device and from it enters the engine. Fuel in a diesel engine
the mixture is prepared in the engine itself.
The internal combustion engine (Fig. 73) consists of a cylinder (1) in which the piston (5) moves; the cylinder has two valves (2, 3), through one of which the combustible mixture is admitted into the cylinder, and through the other the exhaust gases are released from the cylinder. The piston with the help of a crank mechanism (6, 7) is connected to the crankshaft, which comes into rotation when forward movement piston. The cylinder is closed with a cover (4).
The internal combustion engine cycle includes four cycles: intake, compression, power stroke, exhaust. During intake, the piston moves down, the pressure in the cylinder decreases, and a combustible mixture (in a carburetor engine) or air (in a diesel engine) enters it through the valve. The valve is closed at this time (Fig. 73 a). At the end of the inlet of the combustible mixture, the valve closes.
During the second stroke, the piston moves up, the valves are closed, and the working mixture or air is compressed (Fig. 73 b). At the same time, the gas temperature rises: the combustible mixture in the carburetor engine heats up to 300-350 ° C, and the air in the diesel engine - up to 500-600 ° C. At the end of the compression stroke, a spark jumps in the carburetor engine, and the combustible mixture ignites. In a diesel engine, fuel is injected into the cylinder and the resulting mixture ignites spontaneously.
When a combustible mixture is burned, the gas expands and pushes the piston and the crankshaft connected to it, performing mechanical work (Fig. 73 c). This causes the gas to cool.
When the piston comes to bottom point, the pressure will decrease. When the piston moves up, the valve opens and the exhaust gas is released (Fig. 73 d). At the end of this cycle, the valve closes.
8. A steam turbine is a disk mounted on a shaft, on which the blades are fixed. Steam enters the blades. Steam heated to 600 ° C is directed to the nozzle and expands in it. When the steam expands, its internal energy is converted into the kinetic energy of the directed movement of the steam jet. A jet of steam enters the turbine blades from the nozzle and transfers part of its kinetic energy to them, causing the turbine to rotate. Turbines usually have several discs, each of which receives a portion of the steam energy. The rotation of the disk is transmitted to the shaft, to which the electric current generator is connected.
Part 1
To determine the specific heat of combustion of fuel, it is necessary to know
1) the energy released during the complete combustion of the fuel, its volume and initial temperature
2) the energy released during the complete combustion of the fuel, and its mass
3) the energy released during the complete combustion of the fuel, and its density
4) specific heat capacity of a substance, its mass, initial and final temperatures
2. 1 kg of water is poured into a vessel at a temperature of 90°C. What is the mass of water taken at 30 °C, which must be poured into a vessel in order to establish a water temperature of 50 °C in it? Neglect the energy losses for heating the vessel and the surrounding air.
1) 1 kg
2) 1.8 kg
3) 2 kg
4) 3 kg
3. In water taken at a temperature of 20 °C, 1 liter of water was added at a temperature of 100 °C. The temperature of the mixture was found to be 40°C. What is the mass cold water? Neglect heat exchange with the environment.
1) 1 kg
2) 2 kg
3) 3 kg
4) 4 kg
4. Air is quickly compressed in a thick-walled tube. At the same time, the internal energy of the air
1) does not change
2) increases
3) decreases
4) first increases, then does not change
5. The gas received an amount of heat of 300 J and did work of 100 J. The internal energy of the gas in this case
1) increased by 400 J
2) increased by 200 J
3) decreased by 400 J
4) decreased by 200 J
6. In an internal combustion engine
1) the internal energy of the working fluid is converted into mechanical energy
2) the piston moves due to the amount of heat transferred to it
3) the mechanical energy of the piston is converted into the internal energy of the working fluid
4) mechanical work is performed due to the energy of the working fluid and the amount of heat transferred to the piston
7. The internal combustion engine makes useful work at
1) compression of the working fluid
2) release of exhaust gas from the cylinder
3) inlet of the working fluid into the cylinder
4) expansion of the working fluid in the cylinder
8. The working fluid in an automobile internal combustion engine is
1) air
2) gasoline
3) a combustible mixture consisting of air and gasoline vapors
4) kerosene
9. The heat engine receives an amount of heat from the heater for a cycle of 200 J and transfers the amount of heat to the refrigerator 80 J. What is the efficiency of the engine?
1) 29%
2) 40%
3) 43%
4) 60%
10. The engine receives an amount of heat of 100 J from the heater and performs useful work of 200 J. What is the efficiency of such an engine?
1) 200%
2) 50%
3) 20%
4) such an engine is impossible
11. Match between physical quantities and their units in SI. For each position of the left column, select the corresponding position of the left column and write down the selected numbers under the corresponding letters
PHYSICAL QUANTITY
A) the amount of heat
B) specific heat capacity
B) specific heat of combustion
UNIT OF VALUE
1) J/kg
2) J
3) J/kg °C
12. Establish a correspondence between physical quantities and their possible changes, analyzing the following situation: “At constant pressure, a gas of some mass expands rapidly. How does the temperature of the gas, its concentration and internal energy change in this case? The numbers in the answer can be repeated. For each position in the left column, select the corresponding position in the left column and write the selected numbers under the corresponding letters.
PHYSICAL QUANTITY
a) gas temperature
B) concentration
B) internal energy
UNIT OF VALUE
1) does not change
2) increases
3) decreases
13. The impact part of a hammer with a mass of 10 tons falls freely on a steel part with a mass of 200 kg. From what height does the impact part of the hammer fall if after 32 blows the part is heated by 20 °C? Heating consumes 25% of the hammer's energy.
Answers
- Fuel types
- Heating and heating
- Cooking food
- Heat transfers and the law of conservation of energy
- Energy and warmth in wildlife
- Thermal mechanisms and engines
Project Method Lesson
- Target:
- to systematize and generalize the previously acquired knowledge on the topic;
- give an idea of the project activity;
- to interest students in research activities;
- develop logical thinking and the ability to generalize;
- learn to apply the acquired knowledge in practice and in everyday life.
Project #1
"Fuels"
Combustion is an exothermic reaction that releases heat. types of fuel into 3 groups: solid, liquid, gaseous . It turns out that from many types of solid fuels, the largest number heat emits brown Chelyabinsk coal, 14300 kJ per 1 kg of fuel, and metallic rocket fuel:
magnesium 24 830 kJ
aluminum 31 000 kJ
beryllium 66 600 kJ
From liquid types: kerosene will light up 43100 kJ per 1 kg of liquid fuel and diesel fuel - 42700 kJ.
Gaseous fuel is distinguished by the release of a large amount of energy per 1 kg of combustible fuel. But the most a large number of energy is released during the combustion of hydrogen - 119 700 kJ.
Project No. 2
"Heating and heating"
1. What is the usual way of heating residential and industrial premises?
2. How can you investigate indoor convection?
3. What other methods of heat transfer exist?
Project No. 3 "Cooking food"
How to make potatoes cook faster?
To make your potatoes cook faster, you need to throw a piece into the pan with potatoes and water before cooking. butter. When heated, it will melt and cover the surface of the water with a thin film. This protective film will prevent the water from evaporating. And the evaporation process is always accompanied by a decrease in the temperature of the liquid and its quantity. We are faced with the following situation: half of the liquid has boiled away, but the potatoes have not yet been cooked, we have to add water and cook further, and this takes extra time.
Project No. 4 "Heat transfer and the law of conservation of energy
1. Offer experiments with simple school equipment for demonstration different types heat transfers and explain them schematically.
2 . When the temperature changes, the body can change its mechanical properties: length, volume, density, elasticity, fragility. Give examples.
Project No. 5 "Energy and warmth in wildlife"
- Some organisms, especially in the resting stage, are able to exist at very low temperatures. For example, spores of microorganisms can withstand cooling down to - 200 C. There are organisms with no constant temperature: frogs, fish, crocodiles, snakes, and with constant: wolves, bears. Body temperature depends on temperature environment. There are many devices to deal with cooling or overheating.
Project No. 6 "Thermal Mechanisms and Engines"
In our lives, we constantly meet with a variety of engines. The operation of heat engines is associated with consumption various kinds energy. The design of the first steam engines had the main parts of all subsequent heat engines: a heater in which the energy of the fuel was released, water vapor as a working fluid and a piston with a cylinder that converts the energy of steam into mechanical work, as well as a cooler necessary to reduce the temperature and pressure of steam.
slide 2
The purpose of the lesson:
Systematization and generalization of previously acquired knowledge on this topic. Lesson objectives: To interest students in research activities; - Develop logical thinking and generalization skills; - Learn to compare and change the acquired knowledge in practice and in everyday life; - Cultivate a sense of collectivism, mutual assistance, the ability to work in groups.
slide 3
“The Russian land can give birth to its own Plato And quick-witted Newtons” M.V. Lomonosov.
slide 4
Let's start the story about warmth Let's remember everything, summarize now
Energy work to a boil. So that laziness is observed evaporation Brains we will not bring to melting, We train them to exhaustion. In teaching we show diligence, Seeing scientific ideas by smell! We will overcome any task, And we will always be able to help a friend. We study the history of science And honor Lomonosov as great, And we show ourselves in work Like an engine with high efficiency! But how difficult life can be With that lady called Warmth!
slide 5
What is called internal energy? How can internal energy be changed? Heat transfer is directly related to such a concept as the amount of heat. What is the amount of heat?
slide 6
Exercise:
Let's characterize the thermal processes we have studied, namely by formulas. Now you will be given sheets with tasks in the form of tables that you must fill out. Working time 3 minutes. After that, you will do a mutual check and everyone will appreciate the work of the person sitting next to you.
Slide 7
Did you know,
that the physicist Walter Nernst was fond of carp breeding? One day someone thoughtfully remarked: “A strange choice. It’s even more interesting to breed chickens.” The scientist calmly replied: “I breed animals that are in thermal equilibrium with the environment. Breeding warm-blooded animals means heating the world space with your money.” Is the scientist's remark correct? The laws of thermodynamics will answer this and other questions.
Slide 8
Blitz - poll:
What is thermodynamics? Let us formulate the principles that are called the laws of thermodynamics. Is it possible to create a perpetual motion machine? Well, since it is impossible to create an eternal one, then what are real-life heat engines? What are the main parts of any heat engine? Name the main types of heat engines.
Slide 9
The man is very wasteful
uses the fuel energy that nature gives us. We, like ungrateful children, squander the inheritance that has accumulated bit by bit over millions of years. Nature is wiser. How does she decide energy problem? You will answer this question in your projects.
Slide 10
Project No. 1 “Types of fuel”
1. Consider the sources of heat that surround us. We consider gas stove, fire, combustion of gasoline, fuel oil, coke in boiler rooms as sources of heat. Combustion is an exothermic reaction that releases heat. Hydroelectric power plants and thermal power plants are also sources of heat, as they provide up to 70% of all electricity, and these are electric stoves, electric fireplaces and other electric heaters.
slide 11
2. Analyze the types of fuel,
After analyzing the combustion of dry fuel, candles, vegetable oil, combustion of ether and using table No. 1, divide the types of fuel into 3 groups: solid, liquid, gaseous. It turns out that of the many types of solid fuels, the greatest amount of heat is emitted by Chelyabinsk brown coal, 14300 kJ per 1 kg of fuel, and metallic rocket fuel: magnesium 24830 kJ aluminum 31000 kJ beryllium 66600 kJ. From liquid types: kerosene will light up 43100 kJ per 1 kg of liquid fuel and diesel fuel - 42700 kJ. Gaseous fuel is distinguished by the release of a large amount of energy per 1 kg of combustible fuel. But the largest amount of energy is released during the combustion of hydrogen - 119,700 kJ.
slide 12
20 wooden torches, thermometer, scales with weights.
Use them to create a problem that mentions combustion. By how much will the air temperature rise in a large cave with a volume of 10 m by 15 m by 5 m if 20 wooden torches, weighing 800 g, are burned there? Initial temperature air about 14?
slide 13
Project No. 2 “Heating and heating”
1. What is the usual way of heating residential and industrial premises? How can you investigate indoor convection? What other methods of heat transfer exist?
Slide 14
2. Prove with instruments,
that the heating of a liquid standing on fire occurs in a convective way. A flask with water is heated on a spirit lamp, at the bottom there are manganese crystals, fixed with a piece of plasticine. 3. Make up a problem that would take into account the heating of some object by the methods of heat transfer known to you. 1. In previous experience burned 10 grams of alcohol. 30% of the received heat was spent on heating. By how much did the temperature of one liter of water rise? 2. The water temperature in the heating boiler is 90?C. The initial water temperature is 10?C. The boiler holds 5m3 of water. How much fuel oil is spent on heating and maintaining the temperature of such a boiler, if the losses are 15%? Assume that heating occurs once.
slide 15
Project #3 “Cooking”
1. What thermal methods cooking you know? In each case, indicate the source of heat energy and the method of heat transfer to the products. In smoke, on fire, on a steam, in an oven, on a fire. 2. Most of our food is cooked in boiling water. How to make potatoes cook faster? To make your potatoes cook faster, you need to throw a piece of butter into a pot with potatoes and water before cooking. When heated, it will melt and cover the surface of the water with a thin film. This protective film will prevent the water from evaporating. And the evaporation process is always accompanied by a decrease in the temperature of the liquid and its quantity.
slide 16
3. Suggest
or look in the literature for some improvement in cooking. The burner of an electric stove can be made from heating elements in the form of rings. Only those rings, the size of which corresponds to the bottom of the pan, will be included in the electrical circuit. 4. Come up with a problem that mentions the process of cooking. How many birch firewood do tourists need to collect for a fire in order to boil a bucket of spring water? The water temperature in the spring is 9°C. Assume that there is no heat loss.
Slide 17
Project No. 4 “Heat transfer and the law of conservation of energy”
1. Suggest experiments with simple school equipment to demonstrate different types of heat transfer and explain them schematically. Boiling water in paper box, heating the thermometer at a distance from the heat source (lamp, tile, peeling off the buttons from the heated flame of the rod).
Slide 18
2. When the temperature changes, the body can change its mechanical properties: length, volume, density, elasticity, brittleness. Give examples. Experiments: heating a coin by friction, a metal needle in a flame (one end of the needle rests on fire or touches it), heating air in a flask with liquid (a column of liquid moves in the tube). 3. How to determine the temperature of an object heated in a flame, if you also have a calorimeter with cold water, a thermometer, scales with weights, tables?
Slide 19
Project No. 5 “Energy and warmth in wildlife”
1. The main law that all thermal processes obey is the law of conservation of energy. All living organisms expend a lot of energy in the process of life (movement, food, hunting). Where do they get energy from?
Slide 20
Are being considered
chemical reactions within the cell. The whole series of these reactions is called internal respiration (tissue, cellular). It is divided into aerobic and anaerobic. The first is associated with the decomposition of certain substances with the participation of oxygen and occurs with a large release of energy, the second - with the oxygen-free conversion of glucose. The breathing of living beings is sometimes called slow burning.
slide 21
Project No. 6 “Thermal mechanisms and engines”
1. Give examples of mechanisms that use thermal energy in their work. Indicate in each case the source of energy, the way of its transformation. In our lives, we constantly meet with a variety of engines. They propel cars and planes, tractors and ships, railroads and rockets. The operation of heat engines is associated with the consumption of various types of energy. The design of the first steam engines had the main parts of all subsequent heat engines: a heater in which the energy of the fuel was released, water vapor as a working fluid and a piston with a cylinder that converts the energy of steam into mechanical work, as well as a cooler necessary to reduce the temperature and pressure of steam.
slide 22
2. Describe the simplest structure of a steam engine.
The simplest structure of a steam engine was created by Heron of Alexandria in the 2nd century BC. BC. It consisted of a stand on which a vessel with handles and filled with water was placed. The device, which was placed in water, resembled a flask. Tubes were placed on four sides. When the firewood was burning, the water boiled and steam fountained from the top pipe. It was the oldest steam engine.
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3. Show by experience
using the equipment of the school laboratory, how can work be done by converting thermal energy. Water is placed in a test tube, which boils, receiving the amount of heat from the combustion of alcohol. And the steam knocks the cork out of the test tube. This is how work is done after the transformation of energy. 4. Suggest a problem that uses the operation of any thermal device.
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Tell us about any device, a device that works due to the thermal energy of the environment.
Not one of the energy sources known today is able to fully meet the growing needs of man in the future. For this, more attention needs to be paid alternative sources or sources operating on the energy of the environment. There are already, for example, “solar batteries” that turn solar energy in electricity using photocells. Many projects have been created to use the power of the tides, the power of the winds, the power of the geysers. There are also projects to use the temperature difference between the surface layers of water in tropical seas and the water temperature at great depths.
Slide 25
I wish you success in all your endeavors. Good luck and thank you all for the lesson.
Golubeva E.S. Entertaining natural science. Boring textbook. - St. Petersburg: "Triton", 2007. Kovaleva S.Ya. The law of conservation of energy in thermal processes // Weekly newspaper of the publishing house "First of September", No. 33, September 1-7, 2012. Lanina. AND I. One hundred physics games. - M.:, “Enlightenment”, 2005. Perelman Ya.I. Entertaining physics. - M.:, "Nauka", 2001. Uvitskaya E.S. Usage biological material in physics lessons. // Weekly newspaper of the publishing house “The First of September”, No. 31, August 16-22, 2012.
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