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The engineers quickly realized that a more suitable fuel than gun powder must be found. About one hundred years after Huygen's experiments, people believed to have found it in illuminating gas. The young Frenchman Philippe Lebon d'Humbersin (1767 - 1804) was celebrated as its discoverer. In 1801, He announced a patent on a gas engine. Due to his early death, he could not, unfortunately, realize his project.
During the next half century, many setbacks hindered a fast development of the engines. The engineers did not succeed in building a stable running piston engine with internal combustion. Partially interesting patents were announced by different engineers, but their execution failed too often. Samuel Brown, who built the first motor vehicle which was documented (1823), was an exception. He used a gas engine developed by himself.
Eugenio Barsanti (1821-1864), an Italian scientist, developed in the early 50s of the 19th century his atmospheric engine. It used a "Voltaic (from Volta) pistol" as ignition mechanism. A spark skipping between two electrodes ignited the gas mixture.
Only in 1860, the Belgian Jean Joseph Etienne Lenoir (1822-1900) had success with his engines, which operated with illuminating gas. He did not invent any new machine, but assembled many well-known sections and built in such a way a double working engine, which was sold very well in the small trade. The engine reached just the poor efficiency of 3%.
Definitions of some words
Illuminating gas : is also known as "town gas". It was used for lighting and heating purposes. As inflammable constituents, illuminating gas contains hydrogen, methane, but also carbon monoxide, which is poisonous.
Explosion engine : In gas engines, fuel burns in a big explosion. In today's combustion engines, explosions do not occur by no means. Although the term "explosion engine" held itself still in the vernacular. An explosion of fuel in the cylinder leads to the notorious "knocking" or "pinking" of an engine.
Atmospheric engine vs. Double working engine
Atmospheric engine
In an atmospheric engine, the actual work is not carried out by the explosion of gas and the following acceleration of the piston. When the piston arrives at its highest point, the air pressure (therefore "atmospheric") and the piston's dead weight drive it into the cylinder below, which contains after the cooling of the gas an almost complete vacuum. The work is transferred to a flywheel. See sketch Otto's atmospheric engine.
Double working engine
The double working engine has a cylinder. On the way from one extreme to the middle of the cylinder, a fuel mixture gets sucked performing work on the piston after the ignition during the other half of the way. On the other side, the discharge of the burned gas takes place at the same time. Now the engine works in the opposite direction, using the same principle. Now, fresh gas flows in from the other side. Picture shown is the lenoir engine.
At Lenoirs time, Alphonse Beau de Rochas (1815-1893) discovered the favourable effect of a compression of the gas mixture. But he could not use this important discovery in the industry. The compression stroke led later to the development of the four-stroke engine by Nikolaus Otto.
At the world exhibition of 1867 in Paris, Nikolaus August Otto's (1832-1891) and Eugen Langen's (1833-1895) success with the atmospheric engine began. The engine was working with illuminating gas, too, and achieved a better efficiency of about 30 percent than the Lenoir engines because of a better technology. During the following 10 years, Otto's atmospheric engine was sold about 5000 times and so it was the first combustion engine that was produced in big quantities. 1869, Otto and Langen founded the gas engine factory "Deutz". Many other engineers also became well-known there, e.g. Wilhelm Maybach or Gottlieb Daimler.
In the animation shown, the mode of operation of an atmospheric engine can be observed. The explosion of illuminating gas, the following acceleration of the piston, the ejection of the cooled gases and then the working stroke. Work is only performed at the flywheel when the piston goes downward, moved by its own weight and the atmospheric pressure. Down in the combustion chamber the fresh gas is ignited by a small flame.
After few years of production, the demand was already satisfied in the small trade. Attempts to replace illuminating gas for petroleum failed too. The burn was too dangerous; the enormous carburetor uneconomical. People already did not believe in a progress with that kind of engines any more, when Otto revolutionized the engine industry with his ingenious inventions.
Combustion engines before Otto
Otto was not the first person who tried to build an engine where the force of the combustion would directly push on the piston. In the centuries before Otto's development of the four-stroke combustion engine, many engineers worked on this issue.
Huygen's explosion engine
Christian Huygens, a scientist from the Netherlands, tried already in 1666 to push a piston upward by the explosion of shooting powder.
How the Huygens engine works
The explosion of gun powder shots the piston upward. When the piston stops at the top of the "cylinder", the gas can escape from the tub (see image). Then, the atmospheric pressure moves the piston back down and the piston lifts another weight (blue). When the piston reaches the bottom of the cylinder, a new explosion can occur.
Unfortunately, the materials could not stand such a big strain yet. Further, an exact processing was a problem. Huygens used for his first attempts a tub of a canon as cylinder. He just did not have the possibility to create such an engine. The development mended the scientists to a combustion outside of the cylinder. Papin, a student of Huygens, finally built one of the first steam engines. Nonetheless only many years later, when the classic steam engine worked already in a lot of factories without any competitors, scientists continued to think about Huygens idea with a combustion in the cylinder.
Already at the beginning there was the idea of propelling ships by steam. Denis Papin was the first who occupied himself with this topic. He succeeded in designing impellers, which he wanted to use on a steam boat. However, it was too early for that and he had to refuse the construction.
The first patent on a ship machine was given to Jonathan Hull. He designed in 1736 a steamboat which should be used in towing. But the very complicated construction with ropes and roles has never been build.
John Fitch
He was interested in steam engines only after 40 years of living.
Fitch's first model was a boat that was propelled by a machine out of brass, which worked on a series of paddles. Fitch showed this model to the american philosophical society in Philadelphia on september the 2nd in 1785. He received in the following years some patents on the right of using steamships on some rivers in america. In 1787 Fitch build his first real steamboat.
The bigest problem for him was the engine. He didn't have any non-leaking cylinder, the condensor wansn't good enough and the valves leaked too. But he could anyway do some travels with it. Henry Voight, a collegue of him invented the surface-condensor, which Fitch used in future on all his boats. The boiler of the boat was also very interesting: Fitch already used a water-tube boiler in 1787. The water was leaded through spiralformed tubes over the fire.
Another boat of Fitch was already very stable and he could make travels with people. This boat did about 2000 to 3000 miles during the regular oparating without having any concrete damages. In 1796, John F. constructed another steamboat that was propelled by some sort of a screw. Two years later, he died.
Patrick Miller and William Symington
These two men have been the pioneers in England concerning steam navigation. In 1788, they build a steamboat which was stimulated by two cylinders. The problem was that the engines were atmospheric machines that used a separate condenser and therefore were inside the patent of James Watt. This was probably one of the reasons why Symington continued his attempts only around 1801. Symington build the "first practical steamboat" the "Charlotte Dundas". He was working with a double-acting steam engine by James Watt. This engine worked directly on the impeller through a connecting rod.
Henry Bell
He was the first one who made regular travels with a steamboat in Europa. Bell built his "Comet" at the beginning of 1812. After doing some improvements were made. He started the regular steam navigation between Greenock in the first weeks of August in 1812 and his public swimming pool in Helensburg. With the the death of Henry Bell in 1830 his steam navigation ended also.
Robert L. Stevens
He was the one who built the first American steamboat travelling on rivers. After him, no significant changes have been made to his technical solutions for this problem. Stevens used an engine from Watt working on a double acting lever. In a few years, he was able to find the technical best solutions. In 1827, he build the North America. This was one of his most successfull ships. Robert S. used two engines inside of it. Each of them had a piston travel of 8 feet. He is said to have reached a velocity of 15 to 16 miles per hour with it. Other of his inventions followed.
Robert Fulton
He is considered as the pioneer of the today's steam navigation. However, his "genius" was limited to assembling competents, which were designed before him by others. Fulton used one of Watt's engines for his "Clermont" and some technical features which were invented by John Fitch and other men. He combined those things and constructed a steamboat that was able to travel the distance New York - Albany three times as fast as everything before him. He was able to found a growing plant, which built the first profitable steam ships.
Development of steam ships
Probably all of us know them, the big Mississippi steamers. The construction of steamships became a big challenge among the ship designers, who wanted to allure the travelers with as much splendor and elegance as possible. But soon, travelling was not the goal any more. The steamers were used by people because of the atmosphere and not to overcome distances.
The last swimming palace that was built costed about 2 million dollars. The expensive item was not the ship but the furniture and other equipment that was often imported from other countries.
Another possibility to gain the travellers favour was to win challenges. The ships had to swim from one point to another as fast as possible. The picture you see beside was taken on such a contest. Mississippi Queen is leading in front of Delta Queen.
Titanic
The Titanic was (and is still) the biggest ocean steamer that was ever built. It had a length of 269 meters. The whole ship was powered by steam power. Inside, there were 29 boilers, each of them with a height of about 5 meters and a weight of 100 tons. The steam was used in a low pressure steam engine.
The development of steamcars
Nicolas Josef Cugnot
When the locomotive was being developed, some engineers also tried to build cars using steam power, which could be used on normal streets. In France, the first attempts were done. The artillery officer, Josef Cugnot, was allowed to build a steamcar, which was paid by the government.
Although the first version of his car was very unpractical - after a quater of an hour of ride, the boiler had to be heated up for the same time -, Cugnot was commissioned to build a bigger style of his car that was able to transport artillery guns. After the first car accident in history Cugnot stopped his work, also because of missing financial support of the government.
Steamcars in England
The leading engineer in the development of steam cars in England was Richard Trevithick. But he had no luck, either, and he had to stop his project because of money problems.
Walter Hancock
After Trevithick, the boom engineers hoped to arrived. Light boilers, which were not less powerful than others, were used. A boiler, built by Hancock, had big success. He used many flat chambers, connected through pipes.
Newer Steam Cars
Stanley
The twins Francis and Freelan Stanley built up a steamcar enterprise in the first two decades of the XX century. In those years, they participated in some challenges. In 1906, they succeeded in building the fastest and never beaten steam car so far. They reached a speed of 205 km/h with it. At the moment, some English steam scientists try to break this old record.
Steam force in agriculture
Many steam cars were built to be utilized in agriculture. Even today some of them are still working. Steam fans often meet in England at steam car meetings, where they present their devices to interested people.
History of the steam engine after James Watt
In 1800, the patent of James Watt was over. The consequence was an enormous mass of inventions with steam as their basis. All those inventors wanted to improve the steam engine. However, there were not many people that could achieve more than just a printed paper of their product.
The evolution of the noncondensing high-pressure steam-engine
James Watt already mentioned the idea of a high-pressure steam engine in his patent of 1769. He did not intend to build such an engine, but he wanted to be sure nobody else would either. Watt thought that it was impossible to create cylinders and pistons that did not leak under high pressure. He probably also thought about the boiler-detonations of some Savery-engines.
Richard Trevithick
He already thought early about building high-pressure steam engines.
However, many critics did not believe a high-pressure steam engine would really do any work. Trevithick found in South Whales an owner of a mine who refused to believe that a locomotive, operating at high pressure, could pull 10 tons on his 10 miles long good course. Trevithick made a bet with him. Then he built the first locomotive in the world and won the bet.
Nonetheless, he did not receive much success with his locomotives. In 1808, he tried again to take the interest of the public. He rented the largest building sites of London and a circular rail system. By paying entrance, everyone was able to shut a glimpse at his new locomotive "Catch me who can." A travel with it was part of the entrance. The conception did however not bring the success Trevithick expected. He, therefore, did other technical inventions.
George Stephenson and the competition at Rainhill in 1829
George Stephensons' inventions have been really substantial for the history of steam locomotives. However, his first attemps did not bring the success he had hoped for. The owners of the mines could not see the advantage of using steam power instead of horses.
Stephenson then invented some locomotives, which have been used on short coal courses. He was not the only man who contributed to the evolution of steam locomotives. In 1829, there was a decision to build a railway line between the two main cities of trade in England. The line had been finished before having concrete thoughts about the way of transport. Many ideas have been sent to the management. Many of them couldn't get realized. The best chances to be carried out had a set of stationary steam-engine which pulled the wagons by means of rope. But George Stephenson wanted them to do a competition of useful locomotives, so they did.
There were four locomotives that had been announced to participate on the competition. One got a damaged during the transportation and did not fit to the rules. Two locomotives had been suspended from the competition, because they had mechanical difficulties. So there was only Stephensons Rocket left. The great advantage of this engine was its tube boiler. It was the secretary of the railway company who designed it. The cylinder operated through some precautions directly on the front axle. After doing some improvements during the tests, the machine was able to pull a passenger wagon with more than thirty persons inside and reached a velocity of 45 km/h (=28 miles/h). A great advantage of this machine was also that it did not get damaged during the tests. The price of the competition was paid fifty-fifty to Stephenson and Booth, the secretary of the railway company and inventor of the tube boiler.
Stephenson build more locomotives.
Steam locomotives
A modern steam engine consists of a double acting steam engine, which works directly on the driving wheels. Water is heated in a boiler to produce steam. The water is leaded in spiral formed tubes over the fire to enlarge the surface. The conveying of steam is regulated by a slide-gate valve, which can be adjusted to choose whenever the engine runs forward or backwards.
James Watt
The engine of Newcomen was very wasteful of coal even if there have been many improvements to the engine. James Watt was a man who wanted to know the exactness of things. He studied the Newcomen engine very precise and was astonished on how there was a need of water to be injected to cool down the steam. He recognized that there was a relevant loss of power. Watt made many studies concerning steam pressure, which he used for his great cognition. He recognized that it was useles to cool down the same vessel and heat it again. In his patent, he formulated among other things two principles:
1.Thermal insulation
The vessel, which worked by means of steam, had to be as hot as the steam itself.
2.Separate condenser
The vessel where the steam is condensed has to be separated from the cylinder and it has to be as cold as the outside temperature. Watt called it the "condenser."
Watt united these two principles in his first steam engine.
Watt's First Steam Engine (1776)
Watts first steam engine was (like the Newcomen-Engine) working at low pressure. The power could of course be enlarged by increasing the steam pressure, but it could also simply be enlarged by building greater cylinders. The advantage was that there was no need to work with high pressure. Therefore, not many detonations of the boiler ocurred.
One of the main problems Watt had was not technical related but of financial crisis. So the partnership with Matthew Boulton was very good for him; it made the base of all the inventions James Watt made.
Natural Expansion of The SteamWatt discovered that there was no need to conduct steam during all the time the piston moved up. The natural expansion of steam can be used. The quantity of steam can be reduced to a fourth. Therefore, the piston did not press with the same force all the time, but Watt found out that this problem could be fixed with a fly-wheel.
Watt's second patent described among other things how the natural expansion of steam could be used. He described six ways of providing a regular running of the engine. He also described the double-acting engine in this patent and all the technical details which are necessary to provide a regular running of it. After a while there was also the idea of converting the up and down-movement of the piston into a rotating movement. Unfortunately, there was a patent of a man on this convertion. Watt and Boulton could go round it by inventing some new drivings. The invented i.e. the so called sun-driving.
James Watt also invented some new technical features of regulating the running of the engine. One of the most important inventions was the fly ball governor, which automatically regulated the conveying of steam.
Thomas Newcomen
When Thomas Newcomen began his first experiments in 1705, many people advised him to do otherwise. He was a simple smith and iron trader. Newcomen consistently thought about Papin's idea of an engine with a free piston. Although many people were dubious and considered it to be impossible to design a piston with a sufficient sealing, he began his work and in 1712 he presented his first engine, which immediately began its work in a mine .
An important advantage of Newcomen's engine compared to Savery's engine is that its power did not depend on the steam pressure but on the quantity of the cylinder. Because of this it was called low pressure steam engine.
Althought the engine needed an enormous amount of coal to work there were some attemps to improve the atmospheric engine. One of the first improvements was the invention of the injection condensation. In this case, the cooling water did not flow over the cylinder, but it was injected directly into the cylinder. The effect was a much faster condensation. Another improvement was the introduction of an automatic control. However, the efficiency was still very low. Much coal was used for just poor power.John Smeaton
John Smeaton was one of the best engineers of his time. He began to optimize Newcomen's engine. He studied, first of all, every detail of the engine and made some experiments with this. Smeaton came to the conclusion that the engine lost much energy because of bad cylinders with unsufficient sealing. In addition, the measures of the parts did not match with each other, for example, the boiler was often too small compared with the cylinder to produce enough steam. He could design engines that worked very well because of better sealings and better measures of the parts.
Thomas Savery
By the end of the 17th century, the mine companies strongly needed new powerful pumps to extract water out of the mines. Many engineers managed to persuade prosperous company owners in favor of their projects, which were often unrealistic and unrealizable. The distrust in such engineers grew, and in 1702 Thomas Savery had serious problems when he published a script in which he described the advantages and the mode of operation of an engine that would transport water out of mines easier. He called his script The Miners Friend. His goal was not to make unrealistic promises. He wanted to explicate to people how his engine worked. Society would then decide whether or not his engine is worth building.
Denis Papin
Denis Papin was an assistant of Huygens. Huygens showed him the gunpowder-engine. The power of this engine was not effective. Papin could at least make the operation of the engine more secure with his invention of a touch-pan. However, the engine firing off was still very dangerous because its material could hardly stand the huge explosions. Papin then thought of his knowledge of water. He knew that water can get "as elastic as air" and also knew that this procedure could be reversed. Therefore, he wanted to create an engine that could produce the "entire emptiness".
Papins atmospheric piston engine
The cylinder was filled up halfway with water before the piston is pushed down to the water. The air can escape through a small tube. If the whole cylinder is heated, the water converts into steam; the steam presses the piston up. In the highest position, a fastener grabs the piston and holds it at the head. When the steam condenses, the atmospheric pressure will press the piston back down. The power stroke does not occur during the vaporizing but during the condensation of steam. Papin intended to lift a weight with a cord over a spool. He calculated that an engine with a piston of 24 inches in diameter and a stroke of 4 feet could lift a weight of 3.5 tons. This would be equal to 1 Horsepower.
His engine was not at all satisfying. The power was limited, because all functions have been inside of one tool (boiler, cylinder, piston)that had to be heated and cooled. Furthermore, the engine was only cooled with fresh air. Papin also invented a geared piston bar, which could turn a cogwheel while the piston slided downward during the work period of the engine. But he could not manage the construction because of his insufficient technical knowledge. There was no hand worker that could produce an example of the engine and his own knowledge was only sufficient for his labour. Papin was more successful in inventing other different things besides steam power.
Some years later, Papin received an order from the count of Kassel. He was asked to build an engine that could lift water to a defined height. The count paid all the covers. Papin developed in his engine some interesting technical details. He used a free-swimming piston which prevented the steam from condensing on the cold water-surface. Furthermore, he invented a safety valve that limited the maximal steam-pressure. Unfortunately, the joints and valves were leaking so the count lost the interest in Papins steam engine and researches.
The Carnot CycleIn the XIX century, Nicolas L. Sadi Carnot made statement concerning the efficiency of engines. He declared that the term "perfectly efficient heat engine" could not be applied to any heat engine. He believed that an engine in which all heat would be converted to mechanical work did not exist. Carnot also believed that the efficiency of a heat engine depended on the difference between the highest and lowest temperature reached in one cycle. That is, in mathematical terms, E = (T1 - T2 ) / T1.The difference of the temperatures is directly proportional to the efficiency of the heat engine. This conception was proved with his thermodynamic cycle (thermodynamic processes that after numerous stages return a system to its initial state) known as the Carnot cycle, which is the basis cycle of all heat engines. This idea is also presented in the second law of thermodynamics stating that there is a limit, less than a hundred percent, in the efficiency of engines.Description of the Carnot Cycle
Stage 1: In the first stage, the piston moves downward while the engine absorbs heat from a source and gas begins to expand. The portion of the graphic from point A to point B represents this behavior. Because the temperature of the gas does not change, this kind of expansion is called isothermic.
Stage 2: In the second stage, the heat source is removed; the piston continues to move downward and the gas is still expanding while cooling (lowering in temperature). It is presented by the graphic from point B to point C. This stage is called a adiabatic expansion (Energy stays)
Stage 3: The piston begins to move upward and the cool gas is recompressed in the third stage. The heat goes to sink. Point C point D represents the decrease in volume and increase in pressure. The engine gives energy to the environment. This stage is called isothermal compression.
Stage 4: In the final stage, the piston to move upward and the cool gas is secluded and compressed. Its temperature rises to its original state. Point C to point D illustrate this behavior; a continuing increase in pressure and decrease in volume to their initial position. Energy stays, so it's an adiabatic compression.
Application in engines
The Carnot Cycle forms the perfect process of a heat engine. Many engineers tried to reach this kind of cycle. Rudolf Diesel had the most success and his engine is nearly as perfect as the Carnot engine.
The Zeroth Law of Thermodynamics
The zeroth law expresses that having in existence three systems, A, B, and C, if A is in equilibrium with C and B is in equilibrium with C, then A and B will also be in equilibrium. All three systems will be in equilibrium in temperature. If any of these systems are in contact with other systems, there will be compensation in the temperature level of all the systems involved. That is, they will all have the same temperature.
The First Law of Thermodynamics
The first law of thermodynamics centralizes, generally, on the existence of the property of energy. It states: "For any process involving only the displacement of a mass between specified levels in a gravity field and no externalities to the system, the magnitude of that mass is fixed by the end states of the system and is independent of the details of the process." This law ramifies itself into many other assumptions:
1. Definition of heat.
When two objects that possess different temperatures are brought into contact, a thermodynamic process that establishes an equilibrium of temperatures takes place. Scientists in the XVIII century explained this phenomenon with the concept of "caloric" or heat. This law identified it as a form of energy that could be stored and converted into mechanical energy. It was measured in calories.
2. Uniqueness of work values.
Work is the result of a force acting on a body causing it to move. A specific quantity can be assigned to a work interaction between systems. This number of units of mass is displaced between two specified levels in a gravity field. When work is performed by a system (of a rising weight) it has a positive sign. The unit that identifies work done by energy is the joule.
3. Definition of energy.
When work is done in a system, there is always a change in state. Lets use A as the initial position and B as the final position. In A, there exists a specific amount of energy (EA) that needs work (W) in order for the object to move to B and possess another amount of energy (EB). Therefore, in mathematical terms, EA + W = EB. Its unit of measurement is erg. One calorie is equal to 4.186 x 107 ergs, or 4.186 joules.
4. Conservation of energy.
States that energy can only be modified from one form to another. It cannot be manifested or destroyed. For this reason, the sum of the amount of heat transferred in a system and the work done on the system is equal to an increase in the internal energy in the system. However, this law does not apply to nuclear energy because it is produced when atoms of matter are split or fused. The law of conservation of energy is often combined with the law of conservation of matter. This is because matter can be converted into energy.
5. Impossibility of the perpetual -motion machine of the first kind.
A perpetual- motion machine of the first kind (pmm1) is a hypothetical system in which no energy is required to perform work. In opposition, it is known that a machine needs to have some amount of energy that would be converted to work. Therefore, the ppm1 is an impossible machine.
6. The first law and relativity
According to Einstein's theory of relativity energy of a system is equal to the product of its mass and the square of the speed of light (E = mc2 ). The energy and mass of the system is conserved even when there are processes occurring within the system. Further, if the energy suffers any modifications in the system, then the mass will also be altered.
The Second Law of Thermodynamics
The second law of thermodynamics focuses mainly on the equilibrium states of systems and processes that associate these states with others. The word equilibrium signifies that with time the state of a system will remain unchanged while being isolated from any other systems that may be found in an environment. It states: "Among all the allowed states of a system with specific values of energy, constraints, and numbers of particles, one and only one is a stable equilibrium state." Other hypotheses have been inferred from this law.
1. State principle.
As already known, the equilibrium state of a system corresponds to the values of energy, constraints and numbers of particles in that system. The state principle declares that the values of any property of a system in a state of equilibrium can only be expressed as a function of the values of energy, constraints and numbers of particles.
2. Reversible and irreversible processes.
If a system and its environment can change states and are capable of restoring their original states it is called a reversible process. On the other hand, if a system, for example, changes from its initial state to an equilibrium state without affecting its environment it is said to be an irreversible process.
3. Impossibility of the perpetual-motion machine of the second kind.
A system in a stable equilibrium position cannot produce any work but only receive it. If a system in a stable equilibrium state were to produce work, it would cause the system to change to a non-equilibrium state without affecting its environment. This impossible notion is the premise of the perpetual-motion machine of the second kind (pmm2). It is a device that creates work from a stable equilibrium position.
4. Work done reversibly by a system in combination of a reservoir.
If there are two systems A and B that are in a state of mutual equilibrium each system is in a stable equilibrium position. Furthermore, if the state of one of the two systems is altered, while being in contact A with B, the second system will also alter. A combination of system A and a reservoir can experience work directly through each other or indirectly using an intermediate object.
5. Definition of entropy.
Entropy is a measure of the disorder in the system or the measure of how close the system is to equilibrium. It indicates the degree to which a specific quantity of thermal energy is available for performing work. This means the less entropy, the more available the energy. The second law affirms that entropy cannot decrease for any spontaneous process. As an outcome of this law, an engine can deliver work only when heat is transferred from a hot reservoir to a cold reservoir or heat sink.
The Third Law of Thermodynamics
By virtue of the second law, an absolute zero temperature is included in an absolute temperature scale. The third law of thermodynamics remarks that absolute zero cannot be obtained easily by any procedure. It is only possible to approach absolute zero, but impossible to reach it. This law also defines the term zero entropy by stating that all bodies at absolute zero would have the same entropy.
The word thermodynamics originates from the Greek words therme (heat) and dynamis (force). It is the branch of physical science that studies the physical properties of macroscopic systems of matter and energy including any spontaneous conditions, modifications or interactions that may occur between them. In other words, it deals with the mechanical actions or relations of heat. This science utilizes many variables such as pressure, volume, density, temperature and specific heat, to facilitate the description of macroscopic systems; the description of the behavior of an object and its relation to its environment.
Thermodynamics is considered one of the most important branches of physics due to the fact that it involves fundamental laws and principles that relate to all the different fields of engineering and science. It began developing in the XIX century when the study of heat and its ability to produce mechanical work became of great interest. However, the first thermodynamic term employed was "temperature" in the VII century. Galileo, an Italian physicist and astronomer, invented the first primitive thermometer. Then, Jean Ray and the grand duke Ferdinand II of Tuscany created other types of thermometers that employed different sources. The objective of these individuals was to manifest an instrument that would define the undefined; measure quantities that were unknown.
Soon, many questions arised in the thoughts of a selected few. Questions concerning the transferring of energy from one body to another. Was it temperature that was being passed? This was a dubious inquiry that many hoped to answer. The best absolution was found in the study of a new science established by Joseph Black in 1770 called the calorimetry. It is the science of measuring quantities of heat expressed in calories. The calorimeter was a stirring device used to measure the amount of heat of a substance. This new science was based upon many postulates established by Black that were later, toward the end of the XVIII century, contradicted by an American colonial physicist and engineer, Benjamin Thompson. Nearly half a century, James Prescott Joule, an English physicist, later presented more refined theories.
Joule founded the first law of thermodynamics in the 1840s by demonstrating that the quantity of work necessary to cause a given change of state is independent of the type of work (electric, mechanical, etc.), the method of delivering or the rate of doing work. He also concluded that work could be converted into heat and heat into work.
Sadi Carnot, a French engineer who had created the Carnot engine in 1824, introduced the concept of the Carnot cycle. This conception distinguished the interactions of systems from the modifications of their states. In 1850, Rudolf Julius Clausius, a German physicist and mathematician who had enunciated two laws and contributed to the expansion of the study of this science, was intrigued by Carnot's notion. Consequently, it came to assertion that his principle is a postulate and, as a result, it became the second law of thermodynamics. Although in 1849 William Thomson, also known as Lord Kelvin, announced that there was a conflict between the conclusions carried out by Joule and the arguments on caloric Clausius settled this dilemma a few years later.
He established a property called entropy, which was included it in the second law and redefined the first and second law more explicitly.
After the flourishing of this new science, Lord Kelvin's interest in the study of temperature had grown. He, inclusively, instituted various definitions for thermodynamic temperature scales named after him. Not long after, a physicist of Edinburgh and Cambridge called James Clerk Maxwell asserted the zeroth law of thermodynamics.
Throughout the years, many other ingenious European and American mathematicians and physicist such as J. Willard Gibbs, Max Planck and Henri Poincaré, contributed notions and theorems that were very much valuable for the enhancement of the study of thermodynamics.
In the XVIII century, in 1918, a Nobel Prize winning German chemist, Walther Nernst, stated the Nernst theorem, which became the third law of thermodynamics.
Link about thermodynamics
http://www.blueneptune.com/~xmwang/physDemo.htmlhttp://didaktik.physik.uni-wuerzburg.de/~pkrahmer/home/thermo.html
