Complete apparatus has a 15cm adjustable scale, marked in mm, to help prevent parallax error Scale is mounted on sturdy 30cm support rod Apparatus is situated on a sturdy wooden base Includes 9 slotted masses and hanger, each weighing 10g, for a total of 100g Ideal for demonstrating Hookes Law which states the force needed to extend or compress a spring by some distance is proportional to that distance The Hookes Law Apparatus is used to demonstrate that the relationship between the extension on a spring is proportional to the load applied to it. The complete apparatus has a 15cm adjustable scale, marked in millimeters, to mitigate parallax error. The scale is mounted on sturdy 30cm support rod and a wooden base. A hook supporting a coiled spring with a 10g mass hanger and indicator is attached to rod. Nine additional 10g slotted masses are included, for a total of 100g. Includes instructions.