(Space barrier hearing pitch vibration)

1. Sound waves are created by a ___________ of an object.
2. Sound waves do NOT travel in __________because there is no matter for the sound waves to travel through.
3. When a girl sings a very high note, _______________ of her voice is very high.
4. When the sound is too loud, (over 80 decibels) it can cause damaged to ____________.
5. When the jet travels faster than the speed of the sound it passes the sound ____________.​