science

• A sound is a form of energy
• A medium is necessary for sound waves to propagate
• Sound can travel through air
• Sound travels in one direction like a flashlight beam
• Sound energy can be changed into other forms of energy
• Loudness and pitch of sounds are not the same things
• Sound travels at different rates in different media
• Vibration


  An object vibrates to produce sound
• Back and forth motion

  The vibrating object causes air molecules to move back and forth
• Frequency


  Determines the pitch of the sound waves produced by its source
• Temperature increases


  Sound travels faster
• Compression


  A region in a sound wave where the particles are pushed closer together
• Rarefaction


  A region in a sound wave where the particles are spread apart the most
• Decibel scale labels


  • Faint
  • Moderate
  • Very loud
  • Painful
  • Extremely loud
• Frequency


  The number of vibrations each second
• Amplitude increases


  Sound is louder
• Decibel (dB)


  Unit of measurement for the loudness of sound
• Sound travels fastest through solids
• Wavelength


  The distance from one crest to another or one trough to another of a wave
• Ultrasonic


  Pitches above 20,000 Hz
• Echo


  A reflected sound wave