The Laws of Thermodynamics - Essay Example

?Insert of Thermodynamics The laws of thermodynamics are a set of four laws developed to come up with an explanation for the variations in the physical quantities of heat. Thermodynamics on the same note is a branch of physics which deals with the transfer of heat on substances of various types and materials. This is set of three laws each explaining the behavior of heat in certain materials. The basic thermodynamics variables are temperatures, heat and entropy. The three variables are the physical quantities that keep on changing from one material to another depending on the surrounding conditions around the material. A physical quantity is defined by the sequence of operations used to determine its value (Wiliamson). The grouping of several physical quantities to find out the values of each in relation to each other is what constitutes a physical law which is defined as. The laws of thermodynamics relate the heat with temperature changes in materials of different kinds. To be clearer on this, let us begin by defining the various laws of thermodynamics. To begin with the first laws which states that Heat is a form of energy, and energy is conserved (Wiliamson). Here the first law confirms that heat is a form of energy and that it can be conserved. This is seen when we use electricity in our homes, the electrical energy is usually stored in the form of water which is then used to drive turbines hence generating electricity which we often use in our homes. This can always be conserved to minimize wastages by either conserving the water stored in a dam or switching off the electricity when not in use. The second law of thermodynamics can be stated in three different ways as defined by three different scholars. For our study we are going to use the definition of Kelvin which states that No cyclic process exists which produces no other effect than the extraction of heat from a body and its conversion into an equivalent amount of work (Wiliamson). The second law of thermodynamics here brings out the reversibility of thermodynamic processes, that is heat is never lost to the surrounding environments given that all factors such as heat loss to the surroundings through evaporation and other heat transfer processes are under control. This is always carried out in the laboratory by using a calorimeter, a laboratory instrument which is used to measure the amount of heat generated through chemical reactions and other physical changes. The calorimeter is designed for this purpose as it is made in such a way that it can minimize heat loss to the surrounding environment as well as heat gain from the same thus ensuring that heat contained in the materials is the same that is used in the entire experiment. It was upon the realization of the limiting factors in the definition of the term temperature by the two thermodynamic laws that the Zeroth law was devised the help in bridging the gap that was omitted. The zeroth law suggests that If two systems are in thermal equilibrium with a third system, then they are in equilibrium with each other (Wiliamson). This law enables one to order systems according to the direction of heat flow when these two systems are put into contact with each other. For this reason, a system is said to be hotter if heat flows from it into the other system which in this case is considered a colder one than the other when these two systems are put into contact with each other. The reverse is however true in the other direction. The third law of thermodynamics on the other and explains that the entropy of a system approaches a constant value as the temperature approaches absolute zero (Wiliamson). This law suggests that all motions in a material tend to come a standstill, cease within that particular material as the temperature of that material reduces to absolute zero. All materials however must reach a state whereby the temperatures reduce to absolute zero hence no thermodynamic motions occurring within them. The three laws of thermodynamics can be proved in a laboratory experiment as described in the following statements; this experiment will involve the use of a calorimeter in the form of a thermos flask which will minimize the amount of heat lost to the surrounding or gained from the surrounding environments. This is done by fitting the lid to prevent heat loss through evaporation, the two double walls enclosing a vacuum in between them to prevent heat loss through radiation. The thermos flask therefore acts as a perfect heat insulator hence suitable for our experiment. The apparatus shall be arranged as shown in the diagram below. The procedure for carrying out the experiment begins by measuring the mass of the empty calorimeter can, mc then that of the water to be used in the same experiment mw the specific heat capacity of both the calorimeter and the water are known since they are made up of known materials. The mass of the metal sample used will be measured as well and recorded down mob. Half fill the calorimeter can with water and Measure the temperature of the water in the calorimeter before putting in the hot metal T1, this will be the temperature of the can and the water contained in it. Drop the metal sample in a hot water or heat it to a certain temperature and record it T2. Allow the set up to rest until both the metal and the water in the calorimeter shall have attained the same temperature and then measure the final temperature of the water in the whole set up T3. We will find out at the end of the experiment that the temperature of the water in the container is the same as that of the metal bar which was placed in the cold water at a temperature higher than the final one. The rise in temperature of the water and the loss of heat by the metal sample complies to the laws of thermodynamics which are related in a manner that the heat lost by the metal to the cold water in the calorimeter is conserved in the water which has gained the same amount of heat thus heat energy is conserved here. In conclusion we observe from the experiment that the amount of heat lost by an object is actually acquired by another object which may as well lose it to the surroundings. The heat energy in normal cases therefore is not lost to for good by hot objects but is rather acquired and conserved by another object proving the first law of dynamics. The lost heat in this case has done a corresponding amount of work which in our case is heating the cold water in the calorimeter. Practically, therefore the amount of heat gained is equivalent to the amount of heat lost by the metal sample thus yielding to Kelvins observation on the second law of thermodynamics. The temperatures of the two substances remain constant at some point with the temperature of the metal approaching the absolute zero as it loses heat to the water proving so well the third law of thermodynamics. Works Cited Wiliamson, P. Laws of Thermodynamics. New York: Prenceton Publishers, 2002. Read More