1.  In fact, vibrations travel through solid objects at fixed speeds, just as sound travels through air at a fixed speed.

2.  A survival whistle will save your lungs and its sound travels farther than a voice.

3.  By lining up along the spin axis, iron crystals might make the inner core stiffer along the axis, thus making sound travel faster in that direction.

4.  Man-made noise may harm marine mammals, especially since sound travels faster through water than air.

5.  Sound travels faster at the surface and more quickly through warmer water.