Thermodynamics - Lab Report Example

It is a common observation that when a hot body is brought in contact with a cold body, transfer of heat takes place from the hot body to the cold body. If both the bodies are identical in material and dimension and the entire system is thermally insulated then it can be found that both the bodies achieve same temperature indicating that the transfer of heat takes place until both the bodies are in the state of thermal equilibrium. This process of heat transfer is known as heat conduction. Conduction in the language of physics can be explained by the phenomenon of transfer of kinetic energy (heat) by interaction between the vibrating particles (lattices) or movement of free electrons in a body.

In this experiment, linear heat conduction in an insulated long slender brass bar as shown in Figure 1 is examined. We assume the brass bar to be of length L, a high temperature is kept constant at one end, and a low temperature on the other. The reason for thermally insulating the brass bar circumferentially is to ensure that heat conduction takes place linearly along the axis of the bar. The equation governing the heat transfer is known as Fouriers Law, and can be is written as: The thermal conductivity is a function of temperature, but it can be treated as a constant over small temperature ranges.

The thermal conductivity of a material is dependent on the material and it varies with direction, structure, humidity, pressure and temperature change. The transfer of energy takes place in solids by two methods: We will study Fouriers Law through this experiment by finding the thermal conductivity for brass and comparing this value to the real actual value from one reference experiment. To do this we will calculate the cross sectional area of the bar and the gradient slope from a plot of measured temperatures vs. length. We can then use these values in an arranged version of Fouriers Law to find the thermal conductivity by the following relation; The experimental