What does the graph for the spring show?

The graph for the spring shows a straight line of results passing through zero. This shows the extension is directly proportional to the weight. Therefore the relationships between the extension and force are linear. This graph also proves the spring is elastic because if the weight is removed the extension returns to zero. Although if too much weight is added the graph will curve upwards at the end and become non-linear. The spring has been overstretched and exceeded the limit of proportionality. Therefore it has been inelastically deformed and cannot return its original shape if the force is removed.