Sound Waves and Vibration

Vibration

• A vibration is a back-and-forth motion that creates a disturbance in the air particles around an object.
• Vibrations can be:
  • Mechanical (e.g., guitar string)
  • Electromagnetic (e.g., light wave)

Sound Waves

• Sound waves are a type of mechanical wave that transfer energy through a medium (solid, liquid, or gas).
• Characteristics:
  • Frequency (pitch): number of oscillations per second (Hz)
  • Amplitude (loudness): maximum displacement from equilibrium
  • Wavelength: distance between two consecutive points in phase
  • Speed: dependent on the medium (see below)

Sound Waves in Different Mediums

• Solids:
  • Sound waves can travel through solids with minimal energy loss.
  • Examples: earthquake waves, sound through a metal rod
• Liquids:
  • Sound waves can travel through liquids with some energy loss.
  • Examples: underwater sonar, whale communication
• Gases (Air):
  • Sound waves can travel through gases with significant energy loss.
  • Examples: human hearing, music
• Vacuum:
  • Sound waves cannot travel through a vacuum because there are no particles to transmit the energy.

Key Differences in Sound Wave Propagation

• Speed:
  • Solids: fastest (e.g., 5,960 m/s in steel)
  • Liquids: slower than solids (e.g., 1,482 m/s in water)
  • Gases: slowest (e.g., 343 m/s in air at 20°C)
• Absorption:
  • Solids: minimal energy loss
  • Liquids: some energy loss
  • Gases: significant energy loss