1. Waves Characteristics

2. Waves
Wave – Involves some quantity or disturbance that changes in magnitude with respect to time at a given point and changes in magnitude from place to place at a give time
At a single point the size changes over time
At a single time the size changes over position

3. Waves Waves transfer energy NOT matter
A material that a wave travels through is called the medium
Pulse – A single vibration or disturbance that moves from point to point in a medium

4. Waves
Wave phenomena is common in the physical world. Some waves are visible, some are not. By studying visible waves (water, waves in string or springs) we can learn more about waves we cannot see such as sound and light.

5. Waves
Waves can be classified according to the medium through which they travel
Electromagnetic – There are many types of EM waves (light, microwaves, radio waves) and are produced by an accelerating electric charge. EM waves need no medium
Mechanical – These waves are produced by the vibration of an object and propagate through some material medium for energy transfer

6. Mechanical Waves
Mechanical waves work by displacing matter. There are 2 basic types:
Transverse – The displacement of the particles of the medium is perpendicular to the direction of wave propagation
Longitudinal (compression) – The displacement of the particles is parallel to the direction of the propagation of the wave

8. Wave Fronts
Wave Front – The portion of a wave in which particles are all in the same phase of motion (generally a crest)
At the indicated moment in time all of the particles in the medium are “up” or in phase along the wave front

9. Wave Fronts

10. Periodic Waves
In a periodic wave the matter moves (vibrates) at a regular interval of time (T), called the period of vibration.
In order for a periodic wave to continue, energy must be supplied to the source at the same rate that it is carried away by the wave

11. Wave Characteristics
Wavelength ( ) – distance between concurrent points on a wave
Amplitude (a) – Maximum displacement of medium from equilibrium
Frequency (f) – The number of waves (cycles) per second (Hertz)
Period (T) – The time required for 1 cycle
Velocity (v) – the “speed” of the wave

12. Wave Characteristics Amplitude Frequency
Related to “loudness” for sound
Related to “brightness” for light
Frequency
Related to the note (pitch) for sound
Related to color for light

13. Wave Equation
The velocity of any wave is equal to the product of the waves frequency (in Hz) times the wavelength (in m)

14. Wave Equation The wave energy travels in a period of time T
We know that velocity is the time rate of change of displacement

15. Wave Equation