sound

• What are sound waves primarily composed of?

  Vibrations passing through molecules
• How do sound waves travel through materials?

  By causing particles to vibrate
• What are compressions in sound waves?

  Regions where particles are closest together
• What are rarefactions in sound waves?

  Regions where particles are furthest apart
• How do sound waves behave in solids?

  They cause particles to vibrate and collide
• Why does sound travel faster in solids than in gases?

  Particles are more densely packed in solids
• Why can't sound travel through a vacuum?

  There are no particles to vibrate
• What happens to sound waves when they move between different mediums?

  Their speed changes, but frequency remains constant
• What does the equation speed = frequency × wavelength imply when speed increases?

  Wavelength must increase if frequency stays the same
• How does wavelength change in higher density mediums?

  Wavelength gets longer as sound speeds up
• What happens to wavelength in low density materials like air?

  Wavelength gets shorter as sound slows down
• What is refraction in relation to sound?

  Sound can change direction when moving between mediums
• What surfaces reflect most sound waves?

  Hard flat surfaces
• What is an echo?

  A reflection of sound waves from surfaces
• What are the main parts of the human ear involved in hearing?

  • Ear canal
  • Eardrum
  • Ossicles (three small bones)
  • Semicircular canals
  • Cochlea
  • Auditory nerve
• What happens when sound waves reach the ear?

  They travel along the ear canal to the eardrum
• What do vibrations of the eardrum cause?

  They are transmitted through the ossicles
• What does the cochlea do with vibrations?

  It converts them into electrical signals
• How does the brain interpret electrical signals from the cochlea?

  As sounds with varying pitches and volumes
• What frequency range can humans generally hear?

  20 hertz to 20,000 hertz
• How does age affect human hearing?

  Hearing range typically decreases with age
• What causes the decrease in hearing range as we age?

  Wear and tear of the cochlea and auditory nerve
• What is the frequency range of ultrasound?

  Above 20,000 Hertz
• How do some animals like bats use ultrasound?

  For communication or echolocation
• How do humans produce ultrasound?

  Using electrical devices
• What happens when ultrasound hits a boundary between two mediums?

  Some waves are reflected, some transmitted
• What is partial reflection in ultrasound?

  Only some waves are reflected at boundaries
• How can we determine the distance to a boundary using ultrasound?

  By knowing speed and time of reflection
• Why is ultrasound considered safe?

  It does not involve radiation
• What is a common use of ultrasound in medicine?

  Scanning fetuses
• How does ultrasound imaging work for fetuses?

  It processes echoes to create live images
• What indicates a fault in an industrial object using ultrasound?

  Unexpected reflected waves at cracks
• What is sonar used for?

  Sensing submarines and objects underwater
• If a submarine fires ultrasound at 1400 m/s and detects it 6 seconds later, how far is the seafloor?

  4,200 meters
• What equation is used to calculate distance in sonar?

  Distance = speed × time
• Why do we divide the total distance by two in sonar calculations?

  To account for the return trip of the waves
• What are the applications of ultrasound technology?

  • Prenatal scanning
  • Industrial imaging
  • Sonar for underwater detection
• What are the key processes involved in ultrasound imaging?

  1. Sound wave generation
  2. Wave transmission through mediums
  3. Reflection at boundaries
  4. Echo processing to create images
• how is the depth of the boundary calculated

  0.5 x speed x time taken