DiscussionAccording to our experiment, we note that after we filled the boiler with the water, and the boiler is switched on. The temperature starts to increase gradually until 98.0 oC, the water starts to evaporate at this temperature. By the time we close the tap valves, we note that the temperature increases for each 0.5 bar. In addition, the volume of water increases as the temperature increases inside the boiler until it reach to 5 bar where the temperature become maximum and the volume of water vapour is constant. On the other side, as we reverse the process by turning the boiler off cooling process starts. We note that the temperature decreases for each 0.5 bar and the water vapour condenses down. In fact, cooling process is very slow and takes long time from the water to be compressed back again. However, due personal capabilities and machine usage some errors occurred in the experiment in addition to the panel mistakes in collecting the data. Refer to the graph of cooling and heating, we can see the plotted graph that we have from this experiment is a curve for both cooling and heating process. Graph of pressure versus temperature for heating process shows the relation between absolute pressure and the saturated steam temperature for heating process. This graph produces exponential equation which was a curvy line. It shows that as the temperature increases inside the boiler, pressure increases and since the volume is kept constant due to the size of the boiler until the pressure reaches to 5 bar, then the cooling process starts and the water vapour condenses down. Since the volume decrease due to decrease in temperature, the pressure compresses the vapour and converts it into water. So it requires long time to happen, and temperature becomes minimum value when the pressure reaches 0 bar.Graph of pressure versus temperature for cooling process shows relation between absolute pressure and saturated steam temperature for cooling process. The form of curve we have for cooling process is quite similar as for the heating process. This because the decreasing rate of temperature during the cooling process is almost same as increasing rate of temperature during the heating process. But cooling process needs longer time as water cooling slower than heating it up.Initially, technical error occurs during the cooling process. Where the initial value of temperature was taken when the temperature was still increasing even heating switch was turned off. Supposedly the reading of temperature starts being taken after it reaches it maximum value. Besides, temperature where pressure is zero is higher than initial temperature of heating process. The internal surface of the boiler might be oxidised and impurities such as rust (Fe2O3) makes the water impure. Additionally, the thickness of the wall will decrease and overall volume of the boiler will increase. Heat losses also needs more time, this can be seen clearly in both graphs which show the smaller difference in decreasing during cooling process than the heating one. This will cause the results different from saturated steam tables because the volume is assumed to be constant throughout the experiment. Therefore, the cleanliness of the Marcet Boiler should be taken in consideration because it can cause the water inside the boiler mixed with the impurities inside the boiler. These errors can be avoided by washing the boiler before experiment to hinder from the impurities. Water was heated while the wash valve opened to make sure that there is no air inside the boiler which can affect the temperature reading. The air inside the boiler will form a pressure to the surface of the water. So, more extra heat energy needed to change water phase into steam. Water molecules are hard to release from this surface. This mixed pressure will affect the saturated steam temperature.There are also errors that can affect the accuracy of the result such as parallax error. Parallax error is occurs when taking the reading of thermometer and Bourdon measurer. Eyes must be same level as thermometer and cautiously read it to minimize the error. Technical error also occurs where the valve is not closed correctly answer causes some liquid water flowing out. This will also cause the changes of the volume of the boiler. All the errors can be avoided by checking the boiler before we start the experiment.