The only average coefficient of linear expansion to be within its theoretical range was the aluminum rod. The one with the greatest error percentage was the stainless steel. This error could have been due to the old and faulty equipment. For example, two groups were sharing one steam generator, and the steam was leaking out of the sides, and the rods were not heating up as fast as the other two groups who had their own generator. Also, there could have been error when reading the initial micrometer, because if there is any slight movement of the heat exchanger when attaching the hose from the steam generator, it will change the position on the micrometer. In addition to these errors, if an adequate amount of water was not in the steam generator, the rod would not reach its stabilizing temperature to determine its coefficient of linear expansion.

Conclusion

This was a very interesting experiment to work with, because given the materials, you would believe that Stainless Steel would be the obvious choice considering it has the smallest coefficient of expansion. However, given the cost of material and corrosion resistance, I have determined that the best choice is the copper piping. To begin with, the copper piping has the second lowest coefficient of linear expansion compared to the three other materials. In addition to that, it is the only material that is not corrosive when it comes in contact with the hydrochloric acid. This will make it significantly cheaper in the long run, because there will be no need to repair the piping since there is no corrosion from the heated HCl. Compared to the other 3 materials, there will need to be replacement of piping due to corrosion over time. Finally, even though it is not the cheapest material compared to aluminum and brass, it is 41% cheaper than the stainless steel. It is worth it to spend some extra money in comparison to aluminum and brass, in order to create a higher quality pipe given these variables.