Sound Waves Flashcards
What type of waves are sound waves?
Longitudinal
What can change the speed of sound?
The medium it’s travelling through
What is the speed of sound through air?
330m/s
Why can’t sound travel through a vacuum?
Because there are no particles to carry the vibrations
Explain how we hear sound
Sound waves enter the ear canal and cause eardrum to vibrate
Three small bones transmit vibrations to cochlea
This produces electrical signals which pass through the auditory nerve to the brain
Then is interpreted as sound
How do frequencies affect the pitch of a sound?
High frequency waves are high pitched
Low frequency waves are low pitched
How does amplitude affect sound?
High amplitude is loud sound
Low amplitude is quiet sound
What is the normal hearing range of a human?
20Hz-20,000Hz
What frequency sound is Ultrasounds?
Above 20,000Hz
Why can dogs hear ultrasounds and humans can’t?
Different species have different hearing ranges
This is why dogs can hear ultrasounds produced by dog whistles and humans can’t
What do people use ultrasounds for?
Breaking kidney stones
Cleaning jewellery
How do ultrasounds clean jewellery?
Vibrations cause the dirt on jewellery to shake off
How do ultrasounds break kidney stones?
Vibrations cause them to break apart
What is ultrasound imaging used for?
Creates a picture of something that cannot be seen directly such as a unborn baby, faults and defects inside manufactured parts
What happens when ultrasound waves meet at a boundary between two different materials?
Some ultrasound waves are deflected at boundry
Time taken for waves to leave a source and return to detector is measured
Depth of boundry is determined using speed of sound in material and time taken
What is echo sounding used for?
High frequency sounds used to detect objects in deep water and measure water depth
How can distance of reflecting surface or object me calculated with echo sounding?
Using the time taken between pulse of sound being transmitted and speed of sound in water
What is the difference between echo sounding and ultrasounds?
The sound waves for echo sounding are within normal hearing range and to identify objects rather than internal structure
What are seismic waves produced by?
Earthquakes in earths crust
What can earthquakes cause?
Damage to structures and tsunamis
What are the layers of earth from surface to centre?
Crust
Mantle
Outer Core
Inner Core
What are the two types of seismic waves?
P-Waves
S-Waves
What are the properties of P-Waves?
Longitudinal
Fast
Travel through solids and liquids
What are the properties of S-Waves?
Transverse
Slow
Travel through solids
