Slinky Wave Speeds

Introduction

A matter wave is different from a moving particle because it is a temporary disturbance that moves through a medium such as a spring, water, or a metal bar. The disturbance can move between two locations without the matter between the locations.

In this activity you’ll be considering disturbances that move along a Slinky that is stretched and then fixed at each end. There are two types of disturbances that can travel along a stretched Slinky: [1] A few coils at one end can be pulled quickly in a direction that is perpendicular or transverse to the line of stretched coils and released; or [2] A few coils at one end can be bunched together in a longitudinal direction along the line of stretched coils and released.

Objectives

In this activity, you will

• Study movies that show transverse and longitudinal disturbances moving along a stretched Slinky lying on a very slick (low friction) floor.
• Think about the process by which the disturbances propagate along the Slinky, measure the wave speeds, and consider what properties of the Slinky will affect the speed of the waves.