Physics: Chapter 13 - Sound

13.2 Transmission of Sound
Sound waves need a medium in order to travel from one point to another.

13.3 Reflection of Sound
An echo is formed when a sound is reflected off hard, flat surfaces such as a large wall or a distant cliff.

Uses of echos
Use to detect the position of mines and submarines.

13.4 Pitch and Loudness
Pitch
Pitch is related to the frequency of a sound wave.
Sound with lower frequency has a lower pitch.
Sound with higher frequency has a higher pitch.

Loudness
Loudness is related to the amplitude of a sound.
The larger the amplitude, the louder the sound.
The shorter the amplitude, the softer the sound.