Waves

• Wave 


  A disturbance that carries energy from one place to another.
• Transverse waves


  Waves in which the direction of vibration is perpendicular to the propagation of the wave.
• Longitudinal waves


  Waves in which the direction of vibration is parallel to the propagation of the wave.
• Mechanical waves 


  The vibration of particles.
• Electromagnetic waves


  The disturbance/vibration of electric and magnetic (electromagnetic) fields.
• Periodic traveling waves 


  A regularly repeating cycle that appears to move in the direction of propagation of the wave.
• Crest


  The highest point of a transverse wave.
• Trough


  The lowest point of a transverse wave.
• Oscillation/cycle


  One complete vibration of the source.
• Wavelength 


  The distance from a point on a wave to the corresponding point on an adjacent wave.
• Frequency


  The number of waves passing a point per second.
• Amplitude 


  The maxim distance from the undisturbed position(equilibrium).
• Velocity of a wave


  The product of wavelength and frequency.
• Reflection


  When a wave bounces off an object in its path.
• Refraction


  The changing of direction of a wave when it goes from one medium to another.
• Diffraction


  The spreading out of a wave into the space beyond a barrier.
• Interference


  The addition of two or more waves, forming a single resultant wave.
• Constructive interference 


  When two or more waves combine, resulting in a single wave of greater amplitude than the source waves.
• Coherent wave sources


  Wave sources when they produce waves of the same frequency that are either in phase or a constant phase difference apart.
• Waves in phase


  When the crests from one source meet crests from another.
• Destructive interference 


  When two or more waves combine, resulting in a single wave of smaller amplitude than the source waves.
• Waves out of phase

  When the crests from one source meet the throughs from another.
• Interference pattern


  The pattern formed when waves from two (or more) coherent sources combine; it contains a repeating pattern of constructive and destructive interference.
• Polarisation


  When the direction of vibration of a wave is restricted to one plane.
• Doppler Effect


  The apparent change in frequency of waves due to the relative motion between a wave source and observer.