When a body is deformed by the action of a force, the strain produced in it is proportional to the force applied up to a certain point called its elastic limit . The proportionality constant is called the spring constant . We shall see later that the concept of spring constant has important applications to the study of chemistry, in particular to chemical bonds. Beyond the elastic limit, the body is no longer elastic. It becomes plastic so that the strain curve is unpredictable.
Periodic motion means motion with a certain period and frequency.
It repeats itself at equal units of time or a certain number of times every second. Moreover, the type of oscillation that the mass executes is a special type of periodic motion called Simple Harmonic Motion . In this experiment we will study simple harmonic motion by studying the oscillation of a mass on a spring, and also measure its spring constant. The bond strength of the chemical bonds that hold molecules together can be likened to the spring constant of a spring. In fact a good model of a molecule is with the atoms connected together with springs.