Sound

What is Sound? What type of wave is sound? How can we "see" these vibrations? What is Resonance? What is the Doppler Effect?

What is Sound?

Simply put, sound is a type of mechanical wave. This waves is created by a vibrating object.  The wave then travels to our ear.  Once the wave enters our ear, it ends up vibrating a series of parts of our ear.  These parts turn mechanical energy into elctrical energy. Nerves then carry the electrical energy to our brain where it interpretted as sound.

A website that presents a nice set of definitions for sound: Acoustic FAQ

What type of wave is sound?

Sound is a longitudinal wave.  The wave travels as a series of compressions and rarefactions from its source to its reciever.

Page from The Physics Classroom with nice graphics showing a longitudinal wave.

Page from The Physics Classroom with nice graphics showing a pressure wave

How can we "see" these vibrations?

The Art of Sound

Guitar string in slow motion

What is Resonance?

When an object is forced to vibrate at its natural frequency a dramatic increase in amplitude may occur.

Video of the Tacoma Narrows bridge Collapse

What is the Doppler Effect?

The Doppler effect is a percieved shift in frequency of a wave due to the motion of either the source or reciever.

Picture credit: Ron Kurtus

Java Applet about the Doppler Effect