EVALUATION OF RESULTS:

DIFFERENCE BETWEEN THE GRAPHS:

Both graphs display that there is a positive relationship between Force and extension of a material. This means that as Force increases so does the extension of the material.

However, graph 1 displays a linear relationship, whereas graph 2 displays a polynomial relationship. Therefore, the materials Y1 and Y2 (as displayed on graph 1) abide by Hooke’s law and are still within their elastic limit, whilst material Z (as displayed on graph 2) no longer abides by Hooke’s law and has entered its plastic region.

Another key difference between the two graphs is the amount of deformation that occurs as a result of 9 N of force being applied to all three materials. Material Y1 displays 15 mm of deformation, material Y2 displays 19 mm of deformation whilst material Z displays around 725 mm of deformation. This suggests that materials only stay in their elastic region if their deformation is low.

ESTIMATION OF ERRORS:

1. The amount of deformation in mm may have been misread (human error)
2. The calibration of the equipment may not be completely accurate
3. There is an outlier in material Y1 (7 N, 13 mm) this could have been avoided if 3 or more trials were taken of the same material with the repeated forces and the average deformation in mm used.