Making Waves
What is a wave?
A wave is a disturbance in a medium that transfers energy but not matter.
What is the number of waves which pass by in 1 second called?
Frequency (f)
How does the ear transfer sound wave vibrations in air into the inner ear?
The air vibrations make the ear drum vibrate, which causes the middle ear bones (hammer, anvil, stapes) to vibrate, which causes the fluid in the cochlea to vibrate.
How do professional table tennis players use sound to improve their game?
They "listen" for spin on the ball.
Answers may vary. Most would say quickly, because the noise difference between the two is small compared to the time difference.
What is the distance between identical points on adjacent waves?
Wavelength
What is the time needed for the wave motion to repeat itself?
Period (T)
What structure moves with the vibrations of the cochlear fluid, sending signals to the brain?
Hair cells (stereocilia)
How do certain animals use sound to locate things?
They emit high frequency chirps (ultrasound) that echo (bounce) off objects with different densities. These echoes travel back to the animal. The animal uses the time delay between chirp and echo to tell how far away the object is. They also use time and intensity differences between their two ears to perceive where an object is.
When playing a string instrument (guitar, violin, etc.) how do you change the pitch with out tightening the strings?
You hold the string closer to or farther away from the strike point.
What is amplitude?
The distance from equilibrium to a crest or a trough.
What happens to the wavelength if the frequency is doubled?
Wavelength is halved.
What are some things that can cause temporary or permanent hearing loss, either by damaging the hair cells, or some other part of the auditory system?
Examples include repeated exposure to loud noise, drugs/chemicals, old age, disease, etc.
How do structural engineers use sound to find rust?
Ultrasonic transducers emit sound that travels through metal. When the waves encounter rust, they produce an echo, which travels back to the transducer.
When playing a wind instrument (flute, clarinet, palm pipe), how do you change the pitch?
You must effectively change the length of the tube, either by closing/opening holes, or by literally cutting the tube to a certain length.
What is a sine curve?
What happens to the wavelength if the period is tripled?
Wavelength also triples.
What is the frequency range of human hearing?
20 Hz to 20,000 Hz
How do digital cameras make use of ultrasound?
An ultrasonic vibrational device shakes and dislodges dust to clean the camera filter.
Which wave will have more energy if their wavelengths are the same: a high amplitude wave or a low amplitude wave?
What is the SI unit of wavelength?
Meters (m)
What happens to the wavelength if the amplitude quadruples?
Wavelength does NOT change.
What is the threshold for "harmful" noise?
85 decibels
How does the visual microphone work?
Which wave will have more energy if their amplitudes are the same: a short wavelength wave or a long wavelength wave?
Short wavelength wave because of its higher frequency.