Waves come in various types, each with unique characteristics and behaviors. From mechanical waves needing a medium to pulse waves and periodic waves, understanding these distinctions is crucial for grasping wave physics.

Longitudinal and transverse waves differ in particle motion relative to wave propagation. Wave interactions, like interference and superposition, further shape how waves behave in different scenarios, influencing their applications in real-world phenomena.

Types of Waves

Mechanical waves and medium relationship

• Mechanical waves require a medium to propagate through which can be solid (seismic waves), liquid (water waves), or gas (sound waves)
• Energy is transferred through the medium without transferring matter
• Speed of the wave depends on properties of the medium with denser mediums generally resulting in faster wave speeds (sound travels faster in water than air)
• Wavelength and frequency of the wave can be affected by the medium
• Medium determines the type of wave that can propagate
  • Transverse waves require a medium with shear elasticity (solids)
  • Longitudinal waves can propagate through solids, liquids, and gases
• Wave speed is determined by the properties of the medium and can be calculated using the wave equation

Pulse waves vs periodic waves

• Pulse waves are single, non-repeating disturbances that propagate through a medium (a single snap of a rope, a single water droplet falling into a pond)
• Periodic waves are repeating disturbances that propagate through a medium and consist of a series of pulses (sound waves, light waves, ocean waves)
  • Have a definite wavelength, frequency, and period
  • Amplitude determines the amount of energy carried by the wave
• Both pulse and periodic waves transfer energy through a medium
• Both can be transverse or longitudinal

Longitudinal vs transverse waves

• Transverse waves have particle motion perpendicular to the direction of wave propagation
  • Examples include light waves (electromagnetic waves), ripples on a water surface, and waves on a stretched string or rope
• Longitudinal waves have particle motion parallel to the direction of wave propagation and consist of compressions and rarefactions
  • Examples include sound waves in air, liquids, and solids, pressure waves in fluids (hydraulic systems), and seismic P-waves (primary waves) in earthquakes
• Both transverse and longitudinal waves transfer energy through a medium and have wavelength, frequency, and speed properties
• Transverse waves require a medium with shear elasticity (solids) while longitudinal waves can propagate through solids, liquids, and gases

Wave Interactions

• Interference occurs when two or more waves meet and combine
• Superposition principle states that the resultant displacement at any point is the algebraic sum of the individual wave displacements
• Wave fronts are lines or surfaces of constant phase in a wave, perpendicular to the direction of wave propagation