sound

1. vibrations

1.1. propagated by

1.1.1. longitudinal waves

1.1.1.1. through

1.1.1.1.1. compression and rarefraction

1.1.1.2. requires

1.1.1.2.1. A medium

2. loudness

2.1. depends on

2.1.1. amptitude

3. pitch

3.1. depends on

3.1.1. frequency

4. consists of

4.1. ultrasound

4.1.1. produce by

4.1.1.1. vibrations

4.2. audible frequencies

4.2.1. 20Hz-20kHz

4.2.2. produce by

4.2.2.1. vibrations

5. speed

5.1. in

5.1.1. solid>liquid>gas