Sound Flashcards
How is sound produced?
When an object or substance vibrates.
Can sound waves travel through empty space?
No
What is a longitudinal wave?
A wave that moves in the same direction as the direction in which the particles are vibrating.
Can sound waves reflect off surfaces?
Yes
What is an echo?
An echo is a sound caused by the reflection of sound waves from a smooth surface back to the listener.
How do we hear sound?
An ear has an eardrum inside, connected to three small bones. The vibrations in the air make the eardrum vibrate, and these vibrations are passed through the three small bones [called ossicles] to a spiral structure called the cochlea. Signals are passed from the cochlea to the brain to the auditory nerve, and our brain interprets these signals as sound.
What are oscilloscope traces?
A wave pattern seen from the screen of an oscilloscope.
For a wave, what is the amplitude, wavelength and frequency?
The amplitude is the maximum height of a wave from its resting position.
The wavelength is the distance between the crests [tops] of two waves next to each other.
The frequency is the number of waves per second.
What is the pitch?
The frequency of a sound.
At what speed does sound travel at in normal air?
343 metres per second. [717 mph.]
What is the frequency of sound waves measured in?
hertz
What is ultrasound?
Sound with a frequency greater than 20,000 Hz.
