Physics: Sound (P12) Flashcards
Sound waves
Sound waves are longitudinal waves that must pass through a medium. Sound is formed by things vibrating.
Stringed instruments
The string are plucked or bowed to make them vibrate.
Percussion instruments
These instruments are played by striking them and this produces vibrations.
Vibrations
Vibration is the backward and forward movement of the particles.
Speed of sound
330 m/s
Echo
A repeated sound that is caused by the reflection of sound waves from a surface.
Medium
It originates from a definite source and can be distributed or scattered using various means. Unlike light, sound waves can only travel through a medium, such as air, glass, or metal. There cannot be sound in vacuum (space).
Air column
It’s the space of air in a pipe that vibrates with the wind and the result is longitudinal standing waves. The ends, whether open or closed, create nodes or antinodes in these standing waves.
Oscilloscope
Instrument that displays electrical signals that come from converted sound waves, as waves.
Complete vibration
A complete cycle of vibration occurs when the object moves from one extreme position to the other extreme, and back again.
Period (T = 1/v)
The period of a wave is the time required for one complete cycle of the wave to pass by a point.
Frequency (v = 1/T)
It expresses the number of cycles of the repetitive waveform per second.
Hertz (Hz)
It’s the unit of frequency and it is equal to the number of cycles per second.
Pitch
It refers to the specific frequency of a sound wave, which is measured in Hertz (Hz).
Amplitude
It’s the maximum extent of a vibration or oscillation, measured from the position of equilibrium.
