CHAPTER 7. TRANSVERSE PULSES

Transverse pulses 7

Introduction and key

concepts

ESACF

This chapter forms the basis of the discussion into mechanical waves in the following chap-

ters. We begin by discussing pulses. Pulses are disturbances in a medium. If you tap water

in a bucket with your finger, notice that a ripple moves away from the point where you

touched the water. The ripple is a pulse moving away from where you touched the water.

See introductory video: ( Video: VPchw at http://www.everythingscience.co.za)

What is a medium? ESACG

A medium is the substance or material

through which a pulse moves. The medium

carries the pulse from one place to another.

The medium does not create the pulse and

the medium is not the pulse. Therefore the

medium does not travel with the pulse as the

pulse moves through it.

In each medium, the particles that make

up the medium are movedtemporarilyfrom

their rest position. In order for a pulse to

travel, the different parts of the medium must

be able to interact with each other.

A disturbance in water

Picture by mikeyskatie on Flickr.com

DEFINITION: Medium

A medium is the substance or material in which a pulse will move.

124 Physics: Waves, Sound and Light