1. Wave Definitions

2. Elastic Medium
A medium that allows for the transfer of waves by acting as if it were an array of particles connected by springs with each particle having an equilibrium or rest position.
Disturbance
A build up of energy in a system which allows for the propagation of a wave.

3. Pulse
A single non-repeated disturbance.

4. Crest and Trough
A crest is region of upward displacement in a transverse wave.
A trough is an area of downward displacement in a transverse wave.

5. Compression and Rarefaction
A compression is the area of a longitudinal wave where the particles are closer together than the equilibrium position.
A rarefaction is the area of a longitudinal wave where the particles are farther apart than the equilibrium position.

6. Phase
Phase is used to describe the position and direction of motion of a particle on a wave.
Two particles are in-phase if they have the same displacement and are moving in the same direction.
Two particles have opposite phase if they have opposite displacements and are moving in opposite directions.

7. Wavelength
Wavelength is the distance between any two consecutive points on a wave that are in-phase.
The example to the left is only for transverse waves.

8. Frequency and Period
Frequency is the number of oscillation or waves that occur per unit time.
Period is the amount of time that passes as one complete wave passes a given point.

9. Speed = Wavelength • Frequency
Speed is the time rate of motion for a wave.
Speed = Wavelength • Frequency

10. Amplitude Amplitude is the maximum displacement in the y direction.
The amplitude of a wave is an indication of the wave’s energy.