Loudness and Pitch of Sound

The strength or loudness of sound

Depends on the amplitude of the sound wave

Pitch of sound

Depends on frequency of the sound produced

Unit for frequency

Hertz (Hz)

Increase in output power

Louder sound is produced

Increased in frequency

Higher pitch is produced

The Doppler Effect

The apparent change in frequency caused by the relative movement of sound source, the relative movement of the observer or both

Example of The Doppler effect

Frequency of an ambulance siren heard increases when the ambulance approaches the stationary observer