Calculations

From the formula of Electrical power:

and Energy in:

I found values of Electrical power:

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and Energy which was putted into the system:

For finding capacity of material A, was used formula:

and is equal , because before that time material A was just heated, it is proves by Table 1 and gradient of Graph 1. So, going from formula for non-change phase, I got that:

How was wrote before value of was used , then I found the total energy in

, then that value of was used to find capacity of material A:

Propped up from Table 1 and gradient of Graph 1 in part of time from to energy was spent to melt the PCM, so for finding , first all I found on using part of time, which was equal

, so in that phase was equal

and is , after that all work I found , which is gone to be

In the end, all results which needed to find:

 

Errors

 

There are too many different defects which gives many errors on getting results on calculating, making graph and especially calculate errors. Errors in this experiment watches very vividly. The first reason of big errors, that measuring points on thermometer was show different numbers from different point of view. For example, when trying to see what the value of temperature by watching from top getting one number, but from bottom or from left or right another numbers. So it could be that the heat capacity and latent heat in resolution are very different from real specific heat capacity and latent heat. The second reason of errors are that PCM was in little plastic bags and not only in one, material was in two plastic bags and because bags made from plastic, bags have specific heat capacity of that plastic from which bags was made. And some energy from specific heat went to raise temperature of bags, then heat from bags was went to give energy to the material. The third reason it is putting material into bags, it was not clean process, because something which was at bags on contact with water and heat made water yellow, it was clean seen in the end of experiment. The fourth reason, anode and cathode which raised temperature of all system spent some energy to divide water (H₂O) into Oxygen and Hydrogen, that process which was gone is called electrolyze. Vivid example of processing of electrolyze is seen in the end of the experiment, because one side (+ or -) was more pure than another.

As the result of saying about the errors, the inference could be clear; all results which were obtained in this experiment have big and hard solve errors.

 

Conclusion

 

Way of finding specific heat capacity and latent heat of unknown material by considering Voltage(V) and Current(I) of the resistance might useful, but determine all errors and different ways of solving could made work very hard. Which errors should be taken to attention wrote in page 9-page 10 in part ” Errors”. How to solve some problems about errors? First of all, use correct thermometer which shows temperature accurately than that which was used before. Secondly, consider specific heat capacity of bags in solving’s. Thirdly, in putting material into the bag should be used sterilized way. Fourthly, anode-cathode warmer should be changed to the warmer which working with using resistance, like in electric teapot.

To note, using PCM to keep blood cold for hospital is very good resolution. Because it is requires a lot of energy to make PCM melt, this is mean that it will take a long time, as the result blood could be cold long time and it is very good for hospitals of poor countries.