Sound/Ear

Question 1

Sound Waves

Answer 1

• Can travel through
  ○ Solids
  ○ Liquids
  ○ All gases
• Can not travel through
  ○ Vacuums

Question 2

Speed of Sound

Answer 2

• The speed of sound is about 330m/s
• It depends on the temperature – faster in hot air than cold
• Does not depend on the pressure of the air
• Moves thought different materials at different speeds

Question 3

Echoes

Answer 3

• Hard surfaces like walls reflect sound
• SONAR (sound navigation and ranging) uses echoes to map or locate objects in the surrounding environment

Question 4

Speed of sound equation

Answer 4

• Speed = distance travelled/time taken
• Distance = speed*time taken

Question 5

Sound absorption

Answer 5

Soft materials (cushions, curtains etc.) absorb sound and turn it into heat

Question 6

Amplitude

Answer 6

• Amplitude measures how much energy is in the wave
• Big amplitude = big sound

Question 7

Frequency

Answer 7

• Frequency – the number of waves per second.
• Has the units of hertz, Hz
• Wavelength and frequency
• Long wavelength = low frequency
• Short wavelength = high frequency

Question 8

Pitch

Answer 8

• The pitch depends on how many vibrations there are
• The more frequent the vibrations the higher the note
• The fewer the vibrations the lower the note

Question 9

Hearing range

Answer 9

• The frequency range of humans is from 20Hz to 20,000Hz
• Below 20Hz are infrasounds, above 20,000 are ultrasounds

Question 10

Ultrasounds

Answer 10

• Ultrasounds are sounds that are too high (more than 20,000 Hz) for humans to hear
• Uses
  
  • Cleaning things
  • Scan pregnant women

Question 11

Infrasound

Answer 11

• Sound waves with frequencies that are below human hearing range

Question 12

Ear parts

Answer 12

• Outer ear
• Middle ear
• Inner ear

Question 13

Outer ear

Answer 13

• Pinna or auricle
  
  • Part you can see
  • Collects sound waves
• Ear canal
  
  • Wax
    
    • Protects the canal
    • Collects dirt
    • Chemicals that fight off skin infections in the canal

Question 14

Middle ear

Answer 14

• Turn the sound waves into vibrations
  
  • Ear drum
  • Ossicles
    
    • Three smallest bones in your body
      
      • Malleus - hammer
      • Incus - anvil
      • Stapes- stirrup

Question 15

Middle ear – Eustachian tube

Answer 15

• Eustachian tube protects, aerates, and drains fluid from the middle ear
• The Eustachian tube permits the gas pressure in the middle ear cavity to adjust to external air pressure

Question 16

Inner earhearing

Answer 16

• Vibrations from the ossicles enters the cochlea
• Cochlea
  
  • Snail like tube
  • It changes sounds into nerve messages and sends them to your brain.