The HSM7 Extension of springs apparatus is designed for educational institutes to demonstrate Hooke's Law through practical experiments. It comes with steel, powder-coated wall housing and allows the instructor to use any specific spring to carry out experiments. The equipment helps students to study the dependence of spring stiffness on various parameters including the wire diameter, spring diameter, length, number of turns, and material. It has an integral displacement scale to test the relationship between the load applied and the change in length of a spring. The trainer unit is supplied with an instruction manual along with a full set of weights and hangers required to perform experiments.