PROPERTIES OF WAVES Frequency, Wavelength and Velocity

W HAT W AVES M OVE  It is a common misconception that the water in a wave moves in the direction in which the waves are travelling.  This may be because waves arriving at the shoreline move water to and fro across the sand.

W HAT W AVES M OVE  The surfer has acquired kinetic energy and this energy came from the wave.  This example demonstrates one of the most fundamental properties of waves waves transport energy

H OW W AVES M OVE  A medium is a substance through which the wave moves.  Most waves require a medium.  The elastic property of the medium allows the wave to transport, or propagate, energy as the wave travels through the medium.

W AVES The undisturbed surface of the water is known as the medium’s equilibrium position. Regions where the water rises above the equilibrium position are called crests Regions where the water is lower than its equilibrium position are called troughs.

W AVES  In the crest or trough, the magnitude of greatest displacement from the equilibrium is defined as the wave’s amplitude (A).  The distance between successive crests or troughs is called a wavelength ( ).

W AVES  The leading edge of a wave is called the wave front.  A wave front moving out from the point of origin toward a barrier is called an incident wave.  A wave front moving away from the barrier is called a reflected wave.

W AVES  A wave implies a regular repetition of the motion of the medium through which the wave travels.  many parts of the medium are moving in a motion that is identical to the motion

W AVES

T YPES OF W AVES  Most waves travel in a medium.  Light waves are an exception — they do not need a medium in which to travel.  Waves that require a medium in which to travel are called mechanical waves.  In general, there are two main ways in which a medium can be displaced from its equilibrium position.

T YPES OF W AVES 1. A transverse wave is a wave that moves perpendicular to the medium in which it travels. 2. A longitudinal wave is a wave that moves parallel to the medium in which it travels.

T RANSVERSE W AVE 1. A transverse wave is a wave that moves perpendicular to the medium in which it travels.

T RANSVERSE W AVE

L ONGITUDINAL W AVE 1. A longitudinal wave is a wave that moves parallel to the medium in which it travels.

L ONGITUDINAL W AVE