Question

A) List two reasons (other than the expected errors in the dimension meaurements) why your measured value for the density of steel may differ from the accepted value

B) List two reasons that might explain any percent difference between the two values for the density of copper.

Answer 1

The measured value for the density of steel may differ from the accepted value due to the following reasons:

1. The steel sample may consist of internal defects like voids which is not noticible from outside. Due to these voids, the mass obtained for a fixed volume of steel sample would be less then it should be in a void-free sample.

2. Steel is not a pure iron and has many other alloying elements like carbon, manganese, nickel, chromium, etc. The composition of steel varies slightly from sample to sample which may lead to the difference in the measured value.

If two different density measurements are made on same copper sample and they differ, then this is due to measurement inaccuracies. To determine density, mass and volume of the sample has to be determined. So, difference in density values could be due to different measured values of mass and volume in the two measurements.

But, if the density values of two different samples of copper differ, then along with the difference in mass and density measurements, other possible reasons would be:

1. Difference in purity of copper samples. Different concentration of impurity elements lead to change in density values.

2. Presence of inherent defects like voids in the samples. If one of the samples have voids, then its measured density value will be less as compared to the one without voids.

Regards