Sound

1. fastest when

1.1. particles of a medium are closest together

1.2. travelling in a solid > liquid > gas

2. audible frequency

2.1. humans have a frequency range of 20Hz to 20KHz

2.2. frequencies below 20Hz is infrasound

2.3. frequencies above 20KHz is ultrasound

3. speed in air

3.1. 330m/s

4. Pitch

4.1. frequency of the sound wave

5. Waves

5.1. A series of

5.1.1. rarefactions

5.1.2. compressions

5.2. longitudinal

6. Requires a medium

7. Echo

7.1. when a separate sound is heard from reflected sound after an interval of silence

7.2. reflecting surface must be far enough from the source of the sound.

8. Loudness

8.1. amplitude of sound wave

9. Reverberation

9.1. when reflected sound follows closely behind the direct sound that the two cannot be heard as a seperate sound

10. Produced by vibrations