The first type of wave we will see is the "Transverse Wave" or "Sine Wave". This wave oscillates up and down, perpendicularly to the direction in which it travels. Energy is transferred in the direction that the wave travels.


If you are viewing the HTML (web based) or CHM version of this document you will see the animation producing a transverse (sine) wave simulated by many springs. Each blue ball moves up and down vertically but the overall effect is that the wave travels from left to right. This models the transfer of energy by the wave.


Examples of transverse waves are electromagnetic waves, such as light and ripples on the water. If you drop a stone into a still pool you will see transverse waves emanating outwards from the point where the stone entered the water, has circles of increasing radius and correspondingly decreasing amplitude. The amplitude (that is the height of the wave) will decrease in this particular case, that of the stone, because the disturbance was "one-off". If the disturbance is continuous and regular, the waves will be sinusoidal and constant height.


Let's explain some terms concerning waves. In the case of the transverse wave we will look at the frequency, wavelength and amplitude of the wave.



In the diagram shown, you should be able to see that 1 complete wave takes approximately 0.5 of a second, or 2 waves in 1 second. This would be stated as "2 cycles per second" and the unit of frequency is Hertz. Therefore the wave shown below has a frequency of 2Hz.